Merge branch 'pod_update'

* pod_update: (37 commits)
  [Specification] Provide a meaningful error message if a subspec can't be found.
  Update lockfiles of examples.
  Handle pods in (case-insensitive) alphabetical order.
  [outdated] Don’t show pods that can't be checked.
  Fix outdated command.
  Improve Podfile.lock version when the `:head` option is used.
  Improve error message when a local source dir doesn't exist.
  Refactor and cleanup command source files.
  Don't break when a command isn't recognized and trying to show a help banner.
  Changelog.
  [Specs] Minor fix for Lockfile.
  [LocalSource] Specs.
  Changelog.
  Changelog.
  [Lockfile] Fix specs for grammar change.
  [Lockfile] Grammar.
  [LocalSource] Tuning.
  [Lockfile] Encode checksums only if supported.
  [ExternalSources] Better robustness :-)
  [Lockfile] Save checksums as string.
  ...

Conflicts:
	CHANGELOG.md
	Gemfile.lock

CHANGELOG.md

@@ -4,14 +4,46 @@
 
 ###### Enhancements
 
+- Improved installation process:
+  - The installed version of a Pod (recorded in `Podfile.lock`) is preserved
+    across installations and machines.
+  - Pods are reinstalled if the version required changes and is not compatible
+    with current installed one.
+    [#191](https://github.com/CocoaPods/CocoaPods/issues/191)
+  - Pods are reinstalled when their external source changes.
+  - The folders of the Pods not required anymore are removed.
+    [#298](https://github.com/CocoaPods/CocoaPods/issues/298)
+- Introducing `pod update` that installs the dependencies of the Podfile
+  regardless of the contents of `Podfile.lock`.
+  [#131](https://github.com/CocoaPods/CocoaPods/issues/131)
+- Introducing `pod outdated` that show the pods with known updates.
+- Added `:local` option for dependencies.
+  [#458,](https://github.com/CocoaPods/CocoaPods/issues/458)
+  [#415,](https://github.com/CocoaPods/CocoaPods/issues/415)
+  [#156](https://github.com/CocoaPods/CocoaPods/issues/156)
+- Added a meaningful error messages:
+  - in case a podspec couldn’t be found in the root of an external source.
+    [#385,](https://github.com/CocoaPods/CocoaPods/issues/385)
+    [#338,](https://github.com/CocoaPods/CocoaPods/issues/338)
+    [#337](https://github.com/CocoaPods/CocoaPods/issues/337)
+  - in case a subspec name is misspelled.
+    [#327](https://github.com/CocoaPods/CocoaPods/issues/327)
+  - in case a unrecognized commands/argument is provided.
 - The subversion downloader now does an export instead of a checkout, which
   makes it play nicer with SCMs that store metadata in each directory.
   [#245](https://github.com/CocoaPods/CocoaPods/issues/245)
 
 ###### Bug fixes
 
+- The git cache now fetches the tags from the remote if it can’t find the
+  reference.
 - Xcodeproj now builds on 10.6.8 and Travis CI without symlinking headers.
 
+###### Known Limitations
+
+- The SCM reference of head Pods is not preserved across machines.
+- Pods whose inline specification changed are not detected as modified. As a
+  workaround, remove their folder stored in `Pods`.
 
 ## 0.13.0
 
@@ -19,14 +51,18 @@
 
 ###### Enhancements
 
-- Add Podfile `podspec` which allows to use the dependencies of a podspec file. [#162](https://github.com/CocoaPods/CocoaPods/issues/162)
-- Check if any of the build settings defined in the xcconfig files is overridden. [#92](https://github.com/CocoaPods/CocoaPods/issues/92)
+- Add Podfile `podspec` which allows to use the dependencies of a podspec file.
+  [#162](https://github.com/CocoaPods/CocoaPods/issues/162)
+- Check if any of the build settings defined in the xcconfig files is
+  overridden. [#92](https://github.com/CocoaPods/CocoaPods/issues/92)
 - The Linter now checks that there are no compiler flags that disable warnings.
 
 ###### Bug fixes
 
-- The final project isn’t affected anymore by the `inhibit_all_warnings!` option.
-- Support for redirects while using podspec from an url. [#462](https://github.com/CocoaPods/CocoaPods/issues/462)
+- The final project isn’t affected anymore by the `inhibit_all_warnings!`
+  option.
+- Support for redirects while using podspec from an url.
+  [#462](https://github.com/CocoaPods/CocoaPods/issues/462)
 
 
 ## 0.12.0
@@ -35,14 +71,20 @@
 
 ###### Enhancements
 
-- The documentation is generated using the public headers if they are specified.
-- In case of a download failure the installation is aborted and the error message is shown.
+- The documentation is generated using the public headers if they are
+  specified.
+- In case of a download failure the installation is aborted and the error
+  message is shown.
 - Git submodules are initialized only if requested.
-- Don’t impose a certain structure of the user’s project by raising if no ‘Frameworks’ group exists. [#431](https://github.com/CocoaPods/CocoaPods/pull/431)
+- Don’t impose a certain structure of the user’s project by raising if no
+  ‘Frameworks’ group exists.
+  [#431](https://github.com/CocoaPods/CocoaPods/pull/431)
 - Support for GitHub Gists in the linter.
 - Allow specifying ARC settings in subspecs.
-- Add Podfile `inhibit_all_warnings!` which will inhibit all warnings from the Pods library. [#209](https://github.com/CocoaPods/CocoaPods/issues/209)
-- Make the Pods Xcode project prettier by namespacing subspecs in nested groups. [#466](https://github.com/CocoaPods/CocoaPods/pull/466)
+- Add Podfile `inhibit_all_warnings!` which will inhibit all warnings from the
+  Pods library. [#209](https://github.com/CocoaPods/CocoaPods/issues/209)
+- Make the Pods Xcode project prettier by namespacing subspecs in nested
+  groups. [#466](https://github.com/CocoaPods/CocoaPods/pull/466)
 
 
 ## 0.11.1
@@ -52,7 +94,8 @@
 ###### Bug fixes
 
 - Fixed a crash related to subspecs without header files. [#449]
-- Git submodules are loaded after the appropriate referenced is checked out and will be not loaded anymore in the cache. [#451]
+- Git submodules are loaded after the appropriate referenced is checked out and
+  will be not loaded anymore in the cache. [#451]
 - Fixed SVN support for the head version. [#432]
 
 
@@ -65,7 +108,9 @@
 - Added support for public headers. [#440]
 - Added `pod repo lint`. [#423]
 - Improved support for `:head` option and SVN repositories.
-- When integrating Pods with a project without "Frameworks" group in root of the project, raise an informative message. [#431](https://github.com/CocoaPods/CocoaPods/pull/431)
+- When integrating Pods with a project without "Frameworks" group in root of
+  the project, raise an informative message.
+  [#431](https://github.com/CocoaPods/CocoaPods/pull/431)
 - Dropped support for legacy `config.ios?` and `config.osx?`
 
 ###### Bug fixes
@@ -80,16 +125,21 @@
 
 ###### Enhancements
 
-- Added a `--local-only` option to `pod push` so that developers can push locally and test before pushing to a remote. [#405](http://git.io/0ILJEw)
-- Added line number information for errors generated in the Podfile. [#408](http://git.io/fWQvMg)
-- Pods stored in git repositories now initialize submodules. [#406](http://git.io/L9ssSw)
+- Added a `--local-only` option to `pod push` so that developers can push
+  locally and test before pushing to a remote. [#405](http://git.io/0ILJEw)
+- Added line number information for errors generated in the Podfile.
+  [#408](http://git.io/fWQvMg)
+- Pods stored in git repositories now initialize submodules.
+  [#406](http://git.io/L9ssSw)
 
 ###### Bug fixes
 
 - Removed note about the post install hook form the linter.
 - Improved xcodebuild error detection in the linter.
-- Ensure the git cache exists, before updating it, when trying to install the ‘bleeding edge’ of a pod. [#426](http://git.io/d4eqRA)
-- Clean downloaded external pods **after** resolving and activating (sub)specs. [#414](http://git.io/i77q_w)
+- Ensure the git cache exists, before updating it, when trying to install the
+  ‘bleeding edge’ of a pod. [#426](http://git.io/d4eqRA)
+- Clean downloaded external pods **after** resolving and activating (sub)specs.
+  [#414](http://git.io/i77q_w)
 - Support `tar.gz` as filename in a HTTP source. [#428](http://git.io/qhwKkA)
 
 

Gemfile

@@ -7,7 +7,7 @@ group :development do
 
   gem "mocha", "~> 0.11.4"
   gem "bacon"
-  gem "kicker", "~> 3.0.0pre1"
+  gem "kicker", :git => "https://github.com/alloy/kicker.git", :branch => "3.0.0"
   gem "mocha-on-bacon"
   gem "rake"
   gem "rb-fsevent"

Gemfile.lock

@@ -5,6 +5,15 @@ GIT
     xcodeproj (0.3.2)
       activesupport (~> 3.2.6)
 
+GIT
+  remote: https://github.com/alloy/kicker.git
+  revision: 6430787ebf8b9305acc2d2f89ae5cf01d2cd5488
+  branch: 3.0.0
+  specs:
+    kicker (3.0.0pre1)
+      listen
+      terminal-notifier
+
 PATH
   remote: .
   specs:
@@ -41,8 +50,6 @@ GEM
     hashie (1.2.0)
     i18n (0.6.0)
     json (1.7.5)
-    kicker (3.0.0pre1)
-      listen
     listen (0.4.7)
       rb-fchange (~> 0.0.5)
       rb-fsevent (~> 0.9.1)
@@ -74,6 +81,7 @@ GEM
       ffi (>= 0.5.0)
     redcarpet (2.1.1)
     slop (3.3.2)
+    terminal-notifier (1.3.0)
     vcr (2.2.4)
     webmock (1.8.9)
       addressable (>= 2.2.7)
@@ -88,7 +96,7 @@ DEPENDENCIES
   bacon
   cocoapods!
   github-markup
-  kicker (~> 3.0.0pre1)
+  kicker!
   mocha (~> 0.11.4)
   mocha-on-bacon
   pry

examples/AFNetworking Mac Example/Podfile.lock

+
 PODS:
-  - AFNetworking (0.7.0):
+- AFNetworking (0.7.0):
   - JSONKit
-  - FormatterKit (1.0.0):
+- FormatterKit (1.0.0):
   - FormatterKit/ArrayFormatter (= 1.0.0)
   - FormatterKit/LocationFormatter (= 1.0.0)
   - FormatterKit/OrdinalNumberFormatter (= 1.0.0)
   - FormatterKit/TimeIntervalFormatter (= 1.0.0)
   - FormatterKit/URLRequestFormatter (= 1.0.0)
   - FormatterKit/UnitOfInformationFormatter (= 1.0.0)
-  - FormatterKit/ArrayFormatter (1.0.0)
-  - FormatterKit/LocationFormatter (1.0.0)
-  - FormatterKit/OrdinalNumberFormatter (1.0.0)
-  - FormatterKit/TimeIntervalFormatter (1.0.0)
-  - FormatterKit/URLRequestFormatter (1.0.0)
-  - FormatterKit/UnitOfInformationFormatter (1.0.0)
-  - JSONKit (1.5pre)
+- FormatterKit/ArrayFormatter (1.0.0)
+- FormatterKit/LocationFormatter (1.0.0)
+- FormatterKit/OrdinalNumberFormatter (1.0.0)
+- FormatterKit/TimeIntervalFormatter (1.0.0)
+- FormatterKit/URLRequestFormatter (1.0.0)
+- FormatterKit/UnitOfInformationFormatter (1.0.0)
+- JSONKit (1.5pre)
 
 DEPENDENCIES:
-  - AFNetworking (~> 0.7.0)
-  - FormatterKit
+- AFNetworking (~> 0.7.0)
+- FormatterKit
+
+SPEC CHECKSUMS:
+  AFNetworking: 1dd63e737768662b7180659e91846408df4ae7df
+  FormatterKit: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/ArrayFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/LocationFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/OrdinalNumberFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/TimeIntervalFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/URLRequestFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/UnitOfInformationFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  JSONKit: 3d4708953ea7ae399a49777372d8b060a43ddd27
+
+COCOAPODS: 0.13.0

examples/AFNetworking iOS Example/Podfile.lock

+
 PODS:
-  - AFNetworking (0.7.0):
+- AFNetworking (0.7.0):
   - JSONKit
-  - FormatterKit (1.0.0):
+- FormatterKit (1.0.0):
   - FormatterKit/ArrayFormatter (= 1.0.0)
   - FormatterKit/LocationFormatter (= 1.0.0)
   - FormatterKit/OrdinalNumberFormatter (= 1.0.0)
   - FormatterKit/TimeIntervalFormatter (= 1.0.0)
   - FormatterKit/URLRequestFormatter (= 1.0.0)
   - FormatterKit/UnitOfInformationFormatter (= 1.0.0)
-  - FormatterKit/ArrayFormatter (1.0.0)
-  - FormatterKit/LocationFormatter (1.0.0)
-  - FormatterKit/OrdinalNumberFormatter (1.0.0)
-  - FormatterKit/TimeIntervalFormatter (1.0.0)
-  - FormatterKit/URLRequestFormatter (1.0.0)
-  - FormatterKit/UnitOfInformationFormatter (1.0.0)
-  - JSONKit (1.5pre)
+- FormatterKit/ArrayFormatter (1.0.0)
+- FormatterKit/LocationFormatter (1.0.0)
+- FormatterKit/OrdinalNumberFormatter (1.0.0)
+- FormatterKit/TimeIntervalFormatter (1.0.0)
+- FormatterKit/URLRequestFormatter (1.0.0)
+- FormatterKit/UnitOfInformationFormatter (1.0.0)
+- JSONKit (1.5pre)
 
 DEPENDENCIES:
-  - AFNetworking (~> 0.7.0)
-  - FormatterKit
+- AFNetworking (~> 0.7.0)
+- FormatterKit
+
+SPEC CHECKSUMS:
+  AFNetworking: 1dd63e737768662b7180659e91846408df4ae7df
+  FormatterKit: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/ArrayFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/LocationFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/OrdinalNumberFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/TimeIntervalFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/URLRequestFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  FormatterKit/UnitOfInformationFormatter: 12dea999a2df19e389f7b821962fc4088de8b821
+  JSONKit: 3d4708953ea7ae399a49777372d8b060a43ddd27
+
+COCOAPODS: 0.13.0

examples/MGSplitView/Podfile.lock

+
 PODS:
-  - MGSplitViewController (1.0.0)
+- MGSplitViewController (1.0.0)
 
 DEPENDENCIES:
-  - MGSplitViewController (= 1.0.0)
+- MGSplitViewController (= 1.0.0)
+
+SPEC CHECKSUMS:
+  MGSplitViewController: e0b0bc01aa81e1559765c39e7a764c890dac373a
+
+COCOAPODS: 0.13.0

examples/RKTwitter/Podfile.lock

+
 PODS:
-  - FileMD5Hash (0.0.1)
-  - ISO8601DateFormatter (0.6)
-  - JSONKit (1.5pre)
-  - LibComponentLogging-Core (1.2.2)
-  - LibComponentLogging-NSLog (1.0.4):
+- FileMD5Hash (0.0.1)
+- ISO8601DateFormatter (0.6)
+- JSONKit (1.5pre)
+- LibComponentLogging-Core (1.2.2)
+- LibComponentLogging-NSLog (1.0.4):
   - LibComponentLogging-Core (>= 1.1.6)
-  - NSData+Base64 (1.0.0)
-  - RestKit (0.10.2):
+- NSData+Base64 (1.0.0)
+- RestKit (0.10.2):
   - RestKit/JSON (= 0.10.2)
-  - RestKit/JSON (0.10.2):
+- RestKit/JSON (0.10.2):
   - RestKit/Network
   - RestKit/ObjectMapping/CoreData
   - RestKit/ObjectMapping/JSON
   - RestKit/UI
-  - RestKit/Network (0.10.2):
+- RestKit/Network (0.10.2):
   - FileMD5Hash
   - LibComponentLogging-NSLog (>= 1.0.4)
   - SOCKit
   - cocoa-oauth
-  - RestKit/ObjectMapping/CoreData (0.10.2):
+- RestKit/ObjectMapping/CoreData (0.10.2):
   - ISO8601DateFormatter (>= 0.6)
   - RestKit/Network
-  - RestKit/ObjectMapping/JSON (0.10.2):
+- RestKit/ObjectMapping/JSON (0.10.2):
   - ISO8601DateFormatter (>= 0.6)
   - JSONKit (>= 1.5pre)
   - RestKit/Network
-  - RestKit/UI (0.10.2)
-  - SOCKit (1.0)
-  - cocoa-oauth (0.0.1):
+- RestKit/UI (0.10.2)
+- SOCKit (1.0)
+- cocoa-oauth (0.0.1):
   - NSData+Base64 (~> 1.0)
 
 DEPENDENCIES:
-  - RestKit
+- RestKit
+
+SPEC CHECKSUMS:
+  FileMD5Hash: c3b015e6fb293eea0a0c276747f61f20408c2644
+  ISO8601DateFormatter: dc05a2481edf49668d85d3ff8c466c32eb544780
+  JSONKit: 3d4708953ea7ae399a49777372d8b060a43ddd27
+  LibComponentLogging-Core: c80e88f2b7fb204554de7bec13374daf394097e8
+  LibComponentLogging-NSLog: d8f54e7eb65bb893f91cab5864ecf8e85ebd9359
+  NSData+Base64: be7e201540fa7805ecedc1f38d456e008be259b2
+  RestKit: a9f24f857c792183bcc656f891abe93d38e342ee
+  RestKit/JSON: a9f24f857c792183bcc656f891abe93d38e342ee
+  RestKit/Network: a9f24f857c792183bcc656f891abe93d38e342ee
+  RestKit/ObjectMapping/CoreData: a9f24f857c792183bcc656f891abe93d38e342ee
+  RestKit/ObjectMapping/JSON: a9f24f857c792183bcc656f891abe93d38e342ee
+  RestKit/UI: a9f24f857c792183bcc656f891abe93d38e342ee
+  SOCKit: 9d71b00c699cf5aa2989d6aa12f3392b048123db
+  cocoa-oauth: 8f4c8b77c77ac660de37f8125557c4ec09b0118a
+
+COCOAPODS: 0.13.0

examples/RelativePathProject/Podfile.lock

+
 PODS:
-  - AFNetworking (1.0RC1)
+- AFNetworking (1.0RC1)
 
 DEPENDENCIES:
-  - AFNetworking
+- AFNetworking
+
+SPEC CHECKSUMS:
+  AFNetworking: b21c1252d437fd322e7db1caa93b163d76a362cb
+
+COCOAPODS: 0.13.0

examples/SSCatalog/Podfile.lock

+
 PODS:
-  - AFNetworking (1.0RC1)
-  - SSToolkit (1.0.2)
+- AFNetworking (1.0RC1)
+- SSToolkit (1.0.2)
 
 DEPENDENCIES:
-  - AFNetworking
-  - SSToolkit
+- AFNetworking
+- SSToolkit
+
+SPEC CHECKSUMS:
+  AFNetworking: b21c1252d437fd322e7db1caa93b163d76a362cb
+  SSToolkit: 852044205c6a15586431e90f46b2ef01f693285a
+
+COCOAPODS: 0.13.0

examples/TargetTest/Podfile.lock

+
 PODS:
-  - JSONKit (1.5pre)
+- JSONKit (1.5pre)
 
 DEPENDENCIES:
-  - JSONKit
+- JSONKit
+
+SPEC CHECKSUMS:
+  JSONKit: 3d4708953ea7ae399a49777372d8b060a43ddd27
+
+COCOAPODS: 0.13.0

lib/cocoapods.rb

@@ -32,6 +32,7 @@ module Pod
   autoload :Executable,             'cocoapods/executable'
   autoload :Installer,              'cocoapods/installer'
   autoload :LocalPod,               'cocoapods/local_pod'
+  autoload :Lockfile,               'cocoapods/lockfile'
   autoload :Platform,               'cocoapods/platform'
   autoload :Podfile,                'cocoapods/podfile'
   autoload :Project,                'cocoapods/project'

lib/cocoapods/command.rb

@@ -6,20 +6,22 @@ module Pod
     autoload :Install,     'cocoapods/command/install'
     autoload :List,        'cocoapods/command/list'
     autoload :Linter,      'cocoapods/command/linter'
+    autoload :Outdated,    'cocoapods/command/outdated'
     autoload :Presenter,   'cocoapods/command/presenter'
     autoload :Push,        'cocoapods/command/push'
     autoload :Repo,        'cocoapods/command/repo'
     autoload :Search,      'cocoapods/command/search'
     autoload :Setup,       'cocoapods/command/setup'
     autoload :Spec,        'cocoapods/command/spec'
+    autoload :Update,      'cocoapods/command/update'
 
     class Help < Informative
-      def initialize(command_class, argv)
-        @command_class, @argv = command_class, argv
+      def initialize(command_class, argv, unrecognized_command = nil)
+        @command_class, @argv, @unrecognized_command = command_class, argv, unrecognized_command
       end
 
       def message
-        [
+        message = [
           '',
           @command_class.banner.gsub(/\$ pod (.*)/, '$ pod \1'.green),
           '',
@@ -28,6 +30,9 @@ module Pod
           options,
           "\n",
         ].join("\n")
+        message << "[!] Unrecognized command: `#{@unrecognized_command}'\n".red if @unrecognized_command
+        message << "[!] Unrecognized argument#{@argv.count > 1 ? 's' : ''}: `#{@argv.join(' - ')}'\n".red unless @argv.empty?
+        message
       end
 
       private
@@ -48,10 +53,9 @@ module Pod
     end
 
     def self.banner
-      commands = ['install', 'list', 'push', 'repo', 'search', 'setup', 'spec'].sort
-      banner   = "\nTo see help for the available commands run:\n\n"
-      commands.each {|cmd| banner << "  * $ pod #{cmd.green} --help\n"}
-      banner
+      commands = ['install', 'update', 'outdated', 'list', 'push', 'repo', 'search', 'setup', 'spec'].sort
+      banner   = "To see help for the available commands run:\n\n"
+      banner + commands.map { |cmd| "  * $ pod #{cmd.green} --help" }.join("\n")
     end
 
     def self.options
@@ -76,9 +80,9 @@ module Pod
       Config.instance.verbose? ? raise : exit(1)
 
     rescue Exception => e
-      if e.is_a?(PlainInformative) # also catches Informative
+      if e.is_a?(PlainInformative) || ENV['COCOA_PODS_ENV'] == 'development' # also catches Informative
         puts e.message
-        puts *e.backtrace if Config.instance.verbose?
+        puts *e.backtrace if Config.instance.verbose? || ENV['COCOA_PODS_ENV'] == 'development'
       else
         puts ErrorReport.report(e)
       end
@@ -98,18 +102,22 @@ module Pod
 
       String.send(:define_method, :colorize) { |string , _| string } if argv.option( '--no-color' )
 
-      command_class = case argv.shift_argument
+      command_class = case command_argument = argv.shift_argument
       when 'install'  then Install
+      when 'list'     then List
+      when 'outdated' then Outdated
+      when 'push'     then Push
       when 'repo'     then Repo
       when 'search'   then Search
-      when 'list'    then List
       when 'setup'    then Setup
       when 'spec'     then Spec
-      when 'push'    then Push
+      when 'update'   then Update
       end
 
-      if show_help || command_class.nil?
-        raise Help.new(command_class || self, argv)
+      if command_class.nil?
+        raise Help.new(self, argv, command_argument)
+      elsif show_help
+        raise Help.new(command_class, argv)
       else
         command_class.new(argv)
       end
@@ -123,6 +131,25 @@ module Pod
 
     private
 
+    def verify_podfile_exists!
+      unless config.podfile
+        raise Informative, "No `Podfile' found in the current working directory."
+      end
+    end
+
+    def verify_lockfile_exists!
+      unless config.lockfile
+        raise Informative, "No `Podfile.lock' found in the current working directory, run `pod install'."
+      end
+    end
+
+    def update_spec_repos_if_necessary!
+      if @update_repo
+        print_title 'Updating Spec Repositories', true
+        Repo.new(ARGV.new(["update"])).run
+      end
+    end
+
     def print_title(title, only_verbose = true)
       if config.verbose?
         puts "\n" + title.yellow

lib/cocoapods/command/install.rb

@@ -19,8 +19,7 @@ module Pod
 
       This will configure the project to reference the Pods static library,
       add a build configuration file, and add a post build script to copy
-      Pod resources.
-}
+      Pod resources.}
       end
 
       def self.options
@@ -40,17 +39,17 @@ module Pod
         super unless argv.empty?
       end
 
-      def run
-        unless podfile = config.podfile
-          raise Informative, "No `Podfile' found in the current working directory."
-        end
-
-        if @update_repo
-          print_title 'Updating Spec Repositories', true
-          Repo.new(ARGV.new(["update"])).run
+      def run_install_with_update(update)
+        sandbox = Sandbox.new(config.project_pods_root)
+        resolver = Resolver.new(config.podfile, config.lockfile, sandbox)
+        resolver.update_mode = update
+        Installer.new(resolver).install!
       end
 
-        Installer.new(podfile).install!
+      def run
+        verify_podfile_exists!
+        update_spec_repos_if_necessary!
+        run_install_with_update(false)
       end
     end
   end

lib/cocoapods/command/linter.rb

@@ -103,7 +103,9 @@ module Pod
       def install_pod
         podfile = podfile_from_spec
         config.verbose
-        installer = Installer.new(podfile)
+        sandbox = Sandbox.new(config.project_pods_root)
+        resolver = Resolver.new(podfile, nil, sandbox)
+        installer = Installer.new(resolver)
         installer.install!
         @pod = installer.pods.find { |pod| pod.top_specification == spec }
         config.silent

lib/cocoapods/command/outdated.rb

+module Pod
+  class Command
+    class Outdated < Command
+      def self.banner
+%{Show outdated pods:
+
+    $ pod outdated
+
+      Shows the outdated pods in the current Podfile.lock, but only those from
+      spec repos, not those from local/external sources or `:head' versions.}
+      end
+
+      def self.options
+        [
+          ["--no-update", "Skip running `pod repo update` before install"],
+        ].concat(super)
+      end
+
+      def initialize(argv)
+        @update_repo = !argv.option('--no-update')
+        super unless argv.empty?
+      end
+
+      def run
+        verify_podfile_exists!
+        verify_lockfile_exists!
+        update_spec_repos_if_necessary!
+
+        sandbox = Sandbox.new(config.project_pods_root)
+        resolver = Resolver.new(config.podfile, config.lockfile, sandbox)
+        resolver.update_mode = true
+        resolver.update_external_specs = false
+        resolver.resolve
+
+        names = resolver.pods_to_install - resolver.pods_from_external_sources
+        specs = resolver.specs.select do |spec|
+          names.include?(spec.name) && !spec.version.head?
+        end
+
+        if specs.empty?
+          puts "No updates are available.".yellow
+        else
+          puts "The following updates are available:".green
+          puts "  - " << specs.join("\n  - ") << "\n"
+        end
+      end
+    end
+  end
+end
+
+

lib/cocoapods/command/push.rb

@@ -4,7 +4,7 @@ module Pod
   class Command
     class Push < Command
       def self.banner
-        %{Pushing new specifications to a spec-repo:
+%{Pushing new specifications to a spec-repo:
 
     $ pod push REPO [NAME.podspec]
 

lib/cocoapods/command/setup.rb

@@ -2,7 +2,7 @@ module Pod
   class Command
     class Setup < Command
       def self.banner
-        %{Setup CocoaPods environment:
+%{Setup CocoaPods environment:
 
     $ pod setup
 

lib/cocoapods/command/spec.rb

@@ -4,7 +4,7 @@ module Pod
   class Command
     class Spec < Command
       def self.banner
-        %{Managing PodSpec files:
+%{Managing PodSpec files:
 
     $ pod spec create [ NAME | https://github.com/USER/REPO ]
 

lib/cocoapods/command/update.rb

+module Pod
+  class Command
+    class Update < Install
+      def self.banner
+%{Updating dependencies of a project:
+
+    $ pod update
+
+      Updates all dependencies.}
+      end
+
+      def run
+        verify_podfile_exists!
+        verify_lockfile_exists!
+        update_spec_repos_if_necessary!
+        run_install_with_update(true)
+      end
+    end
+  end
+end
+

lib/cocoapods/config.rb

@@ -41,11 +41,16 @@ module Pod
       @project_podfile ||= project_root + 'Podfile'
     end
 
+    def project_lockfile
+      @project_lockfile ||= project_root + 'Podfile.lock'
+    end
+
     def headers_symlink_root
       @headers_symlink_root ||= "#{project_pods_root}/Headers"
     end
 
-    # Returns the spec at the pat returned from `project_podfile`.
+    # @return [Podfile] The Podfile to use for the current execution.
+    #
     def podfile
       @podfile ||= begin
         Podfile.from_file(project_podfile) if project_podfile.exist?
@@ -53,6 +58,14 @@ module Pod
     end
     attr_writer :podfile
 
+    # @return [Lockfile] The Lockfile to use for the current execution.
+    #
+    def lockfile
+      @lockfile ||= begin
+        Lockfile.from_file(project_lockfile) if project_lockfile.exist?
+      end
+    end
+
     module Mixin
       def config
         Config.instance

lib/cocoapods/dependency.rb

@@ -3,9 +3,9 @@ require 'cocoapods/open_uri'
 module Pod
   class Dependency < Gem::Dependency
 
-    attr_reader :external_source, :head
+    attr_reader :head
     alias :head? :head
-    attr_accessor :specification
+    attr_accessor :specification, :external_source
 
     def initialize(*name_and_version_requirements, &block)
       if name_and_version_requirements.empty? && block
@@ -40,7 +40,7 @@ module Pod
     end
 
     def ==(other)
-      super && (@specification ? @specification == other.specification : @external_source == other.external_source)
+      super && (head? == other.head?) && (@specification ? @specification == other.specification : @external_source == other.external_source)
     end
 
     def subspec_dependency?
@@ -76,13 +76,14 @@ module Pod
       if external?
         version << @external_source.description
       elsif inline?
-        version << "defined in Podfile"
+        version << 'defined in Podfile'
+      elsif head?
+        version << 'HEAD'
       elsif @version_requirements != Gem::Requirement.default
         version << @version_requirements.to_s
       end
       result = @name.dup
-      result += " (#{version})" unless version.empty?
-      result += " [HEAD]" if head?
+      result << " (#{version})" unless version.empty?
       result
     end
 
@@ -90,6 +91,10 @@ module Pod
       @external_source.specification_from_sandbox(sandbox, platform)
     end
 
+    def match_version?(version)
+      match?(name, version) && (version.head? == head?)
+    end
+
     # Taken from RubyGems 1.3.7
     unless public_method_defined?(:match?)
       def match?(spec_name, spec_version)
@@ -128,10 +133,13 @@ module Pod
 
     module ExternalSources
       def self.from_params(name, params)
+        return unless name && params
         if params.key?(:git)
           GitSource.new(name, params)
         elsif params.key?(:podspec)
           PodspecSource.new(name, params)
+        elsif params.key?(:local)
+          LocalSource.new(name, params)
         else
           raise Informative, "Unknown external source parameters for #{name}: #{params}"
         end
@@ -158,18 +166,22 @@ module Pod
 
         def specification_from_external(sandbox, platform)
           copy_external_source_into_sandbox(sandbox, platform)
-          specification_from_local(sandbox, platform)
+          spec = specification_from_local(sandbox, platform)
+          raise Informative, "No podspec found for `#{name}' in #{description}" unless spec
+          spec
         end
 
-        def ==(other_source)
-          return if other_source.nil?
-          name == other_source.name && params == other_source.params
+        def ==(other)
+          return if other.nil?
+          name == other.name && params == other.params
         end
       end
 
       class GitSource < AbstractExternalSource
         def copy_external_source_into_sandbox(sandbox, platform)
-          puts "  * Pre-downloading: '#{name}'" unless config.silent?
+          puts "-> Pre-downloading: '#{name}'" unless config.silent?
+          target = sandbox.root + name
+          target.rmtree if target.exist?
           downloader = Downloader.for_target(sandbox.root + name, @params)
           downloader.download
           if local_pod = sandbox.installed_pod_named(name, platform)
@@ -191,8 +203,10 @@ module Pod
         def copy_external_source_into_sandbox(sandbox, _)
           output_path = sandbox.root + "Local Podspecs/#{name}.podspec"
           output_path.dirname.mkpath
-          puts "  * Fetching podspec for `#{name}' from: #{@params[:podspec]}" unless config.silent?
-          open(@params[:podspec]) do |io|
+          puts "-> Fetching podspec for `#{name}' from: #{@params[:podspec]}" unless config.silent?
+          path = @params[:podspec]
+          path = Pathname.new(path).expand_path if path.start_with?("~")
+          open(path) do |io|
             output_path.open('w') { |f| f << io.read }
           end
         end
@@ -201,6 +215,35 @@ module Pod
           "from `#{@params[:podspec]}'"
         end
       end
+
+      class LocalSource < AbstractExternalSource
+        def pod_spec_path
+          path = Pathname.new(@params[:local]).expand_path + "#{name}.podspec"
+          raise Informative, "No podspec found for `#{name}' in `#{@params[:local]}'" unless path.exist?
+          path
+        end
+
+        def copy_external_source_into_sandbox(sandbox, _)
+          output_path = sandbox.root + "Local Podspecs/#{name}.podspec"
+          output_path.dirname.mkpath
+          FileUtils.copy(pod_spec_path, output_path)
+        end
+
+        def specification_from_local(sandbox, platform)
+          specification_from_external(sandbox, platform)
+        end
+
+        def specification_from_external(sandbox, platform)
+          copy_external_source_into_sandbox(sandbox, platform)
+          spec = Specification.from_file(pod_spec_path)
+          spec.source = @params
+          spec
+        end
+
+        def description
+          "from `#{@params[:local]}'"
+        end
+      end
     end
   end
 end

lib/cocoapods/downloader/git.rb

@@ -79,6 +79,7 @@ module Pod
           git! "reset --hard HEAD"
           git! "clean -d -x -f"
           git! "pull origin master"
+          git! "fetch --tags"
         end
       end
 

lib/cocoapods/installer.rb

@@ -7,19 +7,12 @@ module Pod
 
     include Config::Mixin
 
-    attr_reader :sandbox
+    attr_reader :resolver, :sandbox, :lockfile
 
-    def initialize(podfile)
-      @podfile = podfile
-      # FIXME: pass this into the installer as a parameter
-      @sandbox = Sandbox.new(config.project_pods_root)
-      @resolver = Resolver.new(@podfile, @sandbox)
-      # TODO: remove in 0.7 (legacy support for config.ios? and config.osx?)
-      config.podfile = podfile
-    end
-
-    def lock_file
-      config.project_root + 'Podfile.lock'
+    def initialize(resolver)
+      @resolver = resolver
+      @podfile = resolver.podfile
+      @sandbox = resolver.sandbox
     end
 
     def project
@@ -29,7 +22,8 @@ module Pod
       pods.each do |pod|
         # Add all source files to the project grouped by pod
         pod.relative_source_files_by_spec.each do |spec, paths|
-          group = @project.add_spec_group(spec.name)
+          parent_group = pod.local? ? @project.local_pods : @project.pods
+          group = @project.add_spec_to_group(pod.name, parent_group)
           paths.each do |path|
             group.files.new('path' => path.to_s)
           end
@@ -46,8 +40,17 @@ module Pod
       end.compact
     end
 
+    # Install the Pods. If the resolver indicated that a Pod should be installed
+    #   and it exits, it is removed an then reinstalled. In any case if the Pod
+    #   doesn't exits it is installed.
+    #
+    # @return [void]
+    #
     def install_dependencies!
-      pods.each do |pod|
+      pods.sort_by { |pod| pod.top_specification.name.downcase }.each do |pod|
+        name = pod.top_specification.name
+        should_install = @resolver.should_install?(name) || !pod.exists?
+
         unless config.silent?
           marker = config.verbose ? "\n-> ".green : ''
           if subspec_name = pod.top_specification.preferred_dependency
@@ -55,15 +58,14 @@ module Pod
           else
             name = pod.to_s
           end
-          name << " [HEAD]" if pod.top_specification.version.head?
-          puts marker << ( pod.exists? ? "Using #{name}" : "Installing #{name}".green )
+          puts marker << ( should_install ? "Installing #{name}".green : "Using #{name}" )
         end
 
-        download_pod(pod) unless pod.exists?
-
-        # This will not happen if the pod existed before we started the install
-        # process.
-        if pod.downloaded?
+        if should_install
+          unless pod.downloaded?
+            pod.implode
+            download_pod(pod)
+          end
           # The docs need to be generated before cleaning because the
           # documentation is created for all the subspecs.
           generate_docs(pod)
@@ -100,12 +102,26 @@ module Pod
       end
     end
 
+    # @TODO: use the local pod implode
+    #
+    def remove_deleted_dependencies!
+      resolver.removed_pods.each do |pod_name|
+        marker = config.verbose ? "\n-> ".red : ''
+        path = sandbox.root + pod_name
+        puts marker << "Removing #{pod_name}".red
+        path.rmtree if path.exist?
+      end
+    end
+
     def install!
       @sandbox.prepare_for_install
 
       print_title "Resolving dependencies of: #{@podfile.defined_in_file}"
       specs_by_target
 
+      print_title "Removing deleted dependencies" unless resolver.removed_pods.empty?
+      remove_deleted_dependencies!
+
       print_title "Installing dependencies"
       install_dependencies!
 
@@ -119,15 +135,17 @@ module Pod
         generate_dummy_source(target_installer)
       end
 
-      generate_lock_file!(specifications)
-
       puts "- Running post install hooks" if config.verbose?
       # Post install hooks run _before_ saving of project, so that they can alter it before saving.
       run_post_install_hooks
 
-      puts "- Writing Xcode project file to `#{@sandbox.project_path}'\n\n" if config.verbose?
+      puts "- Writing Xcode project file to `#{@sandbox.project_path}'" if config.verbose?
       project.save_as(@sandbox.project_path)
 
+      puts "- Writing lockfile in `#{config.project_lockfile}'\n\n" if config.verbose?
+      @lockfile = Lockfile.generate(@podfile, specs_by_target.values.flatten)
+      @lockfile.write_to_disk(config.project_lockfile)
+
       UserProjectIntegrator.new(@podfile).integrate! if config.integrate_targets?
     end
 
@@ -143,44 +161,6 @@ module Pod
       @podfile.post_install!(self)
     end
 
-    def generate_lock_file!(specs)
-      lock_file.open('w') do |file|
-        file.puts "PODS:"
-
-        # Get list of [name, dependencies] pairs.
-        pod_and_deps = specs.map do |spec|
-          [spec.to_s, spec.dependencies.map(&:to_s).sort]
-        end.uniq
-
-        # Merge dependencies of ios and osx version of the same pod.
-        tmp = {}
-        pod_and_deps.each do |name, deps|
-          if tmp[name]
-            tmp[name].concat(deps).uniq!
-          else
-            tmp[name] = deps
-          end
-        end
-        pod_and_deps = tmp
-
-        # Sort by name and print
-        pod_and_deps.sort_by(&:first).each do |name, deps|
-          if deps.empty?
-            file.puts "  - #{name}"
-          else
-            file.puts "  - #{name}:"
-            deps.each { |dep| file.puts "    - #{dep}" }
-          end
-        end
-
-        file.puts
-        file.puts "DEPENDENCIES:"
-        @podfile.dependencies.map(&:to_s).sort.each do |dep|
-          file.puts "  - #{dep}"
-        end
-      end
-    end
-
     def generate_dummy_source(target_installer)
       class_name_identifier = target_installer.target_definition.label
       dummy_source = Generator::DummySource.new(class_name_identifier)
@@ -215,7 +195,11 @@ module Pod
       specs_by_target.each do |target_definition, specs|
         @pods_by_spec[target_definition.platform] = {}
         result[target_definition] = specs.map do |spec|
+          if spec.local?
+            LocalPod::LocalSourcedPod.new(spec, sandbox, target_definition.platform)
+          else
             @sandbox.local_pod_for_spec(spec, target_definition.platform)
+          end
         end.uniq.compact
       end
       result

lib/cocoapods/local_pod.rb

@@ -45,12 +45,14 @@ module Pod
     attr_accessor :downloaded
     alias_method :downloaded?, :downloaded
 
-    # @param [Specification] specification
-    #   The first activated specification of the pod.
-    # @param [Sandbox] sandbox
-    #   The sandbox where the files of the pod will be located.
-    # @param [Platform] platform
-    #   The platform that will be used to build the pod.
+    # @param [Specification] specification  The first activated specification
+    #                                       of the pod.
+    #
+    # @param [Sandbox] sandbox              The sandbox where the files of the
+    #                                       pod will be located.
+    #
+    # @param [Platform] platform            The platform that will be used to
+    #                                       build the pod.
     #
     # @todo The local pod should be initialized with all the activated
     #       specifications passed as an array, in order to be able to cache the
@@ -96,9 +98,7 @@ module Pod
     #                  the pods comes from a local source.
     #
     def to_s
-      result = top_specification.to_s
-      result << " [LOCAL]" if top_specification.local?
-      result
+      top_specification.to_s
     end
 
     # @return [String] The name of the Pod.
@@ -140,6 +140,10 @@ module Pod
       root.rmtree if exists?
     end
 
+    def local?
+      false
+    end
+
     # @!group Cleaning
 
     # Deletes any path that is not used by the pod.
@@ -508,5 +512,39 @@ module Pod
         Pathname.glob(pattern, File::FNM_CASEFOLD)
       end.flatten
     end
+
+    # A {LocalSourcedPod} is a {LocalPod} that interacts with the files of
+    # a folder controlled by the users. As such this class does not alter
+    # in any way the contents of the folder.
+    #
+    class LocalSourcedPod < LocalPod
+      def downloaded?
+        true
+      end
+
+      def create
+        # No ops
+      end
+
+      def root
+        @root ||= Pathname.new(@top_specification.source[:local]).expand_path
+      end
+
+      def implode
+        # No ops
+      end
+
+      def clean!
+        # No ops
+      end
+
+      def to_s
+        super + " [LOCAL]"
+      end
+
+      def local?
+        true
+      end
+    end
   end
 end

lib/cocoapods/lockfile.rb

+module Pod
+  class Lockfile
+
+    # @return [Lockfile] Returns the Lockfile saved in path.
+    #   Returns {nil} If the file can't be loaded.
+    #
+    def self.from_file(path)
+      return nil unless path.exist?
+      hash = YAML.load(File.open(path))
+      lockfile = Lockfile.new(hash)
+      lockfile.defined_in_file = path
+      lockfile
+    end
+
+    # @return [Lockfile] Generates a lockfile from a {Podfile} and the
+    #   list of {Specifications} that were installed.
+    #
+    def self.generate(podfile, specs)
+      Lockfile.new(generate_hash_from_podfile(podfile, specs))
+    end
+
+    # @return [String] The file where this Lockfile is defined.
+    #
+    attr_accessor :defined_in_file
+
+    # @return [String] The hash used to initialize the Lockfile.
+    #
+    attr_reader :to_hash
+
+    # @param [Hash] hash A Hash representation of a Lockfile.
+    #
+    def initialize(hash)
+      @to_hash = hash
+    end
+
+    # @return [Array<String, Hash{String => Array[String]}>] The pods installed
+    #   and their dependencies.
+    #
+    def pods
+      @pods ||= to_hash['PODS'] || []
+    end
+
+    # @return [Array<Dependency>] The Podfile dependencies used during the last
+    #   install.
+    #
+    def dependencies
+      @dependencies ||= to_hash['DEPENDENCIES'].map { |dep| dependency_from_string(dep) } || []
+    end
+
+    # @return [Hash{String => Hash}] A hash where the name of the pods are
+    #   the keys and the values are the parameters of an {AbstractExternalSource}
+    #   of the dependency that required the pod.
+    #
+    def external_sources
+      @external_sources ||= to_hash["EXTERNAL SOURCES"] || {}
+    end
+
+    # @return [Array<String>] The names of the installed Pods.
+    #
+    def pods_names
+      @pods_names ||= pods.map do |pod|
+        pod = pod.keys.first unless pod.is_a?(String)
+        name_and_version_for_pod(pod)[0]
+      end
+    end
+
+    # @return [Hash{String => Version}] A Hash containing the name
+    #   of the installed Pods as the keys and their corresponding {Version}
+    #   as the values.
+    #
+    def pods_versions
+      unless @pods_versions
+        @pods_versions = {}
+        pods.each do |pod|
+          pod = pod.keys.first unless pod.is_a?(String)
+          name, version = name_and_version_for_pod(pod)
+          @pods_versions[name] = version
+        end
+      end
+      @pods_versions
+    end
+
+    # @return [Dependency] A dependency that describes the exact installed version
+    #   of a Pod.
+    #
+    def dependency_for_installed_pod_named(name)
+      version = pods_versions[name]
+      raise Informative, "Attempt to lock a Pod without an known version." unless version
+      dependency = Dependency.new(name, version)
+      if external_source = external_sources[name]
+        dependency.external_source = Dependency::ExternalSources.from_params(dependency.name, external_source)
+      end
+      dependency
+    end
+
+    # @param [String] The string that describes a {Specification} generated
+    #   from {Specification#to_s}.
+    #
+    #   @example Strings examples
+    #       "libPusher"
+    #       "libPusher (1.0)"
+    #       "libPusher (HEAD based on 1.0)"
+    #       "RestKit/JSON"
+    #
+    # @return [String, Version] The name and the version of a
+    # pod.
+    #
+    def name_and_version_for_pod(string)
+      match_data = string.match(/(\S*) \((.*)\)/)
+      name = match_data[1]
+      vers = Version.from_string(match_data[2])
+      [name, vers]
+    end
+
+    # @param [String] The string that describes a {Dependency} generated
+    #   from {Dependency#to_s}.
+    #
+    #   @example Strings examples
+    #       "libPusher"
+    #       "libPusher (= 1.0)"
+    #       "libPusher (~> 1.0.1)"
+    #       "libPusher (> 1.0, < 2.0)"
+    #       "libPusher (HEAD)"
+    #       "libPusher (from `www.example.com')"
+    #       "libPusher (defined in Podfile)"
+    #       "RestKit/JSON"
+    #
+    # @return [Dependency] The dependency described by the string.
+    #
+    def dependency_from_string(string)
+      match_data = string.match(/(\S*)( (.*))?/)
+      name = match_data[1]
+      version = match_data[2]
+      version = version.gsub(/[()]/,'') if version
+      case version
+      when nil
+        Dependency.new(name)
+      when /defined in Podfile/
+        # @TODO: store the whole spec?, the version?
+        Dependency.new(name)
+      when /from `(.*)'/
+        external_source_info = external_sources[name]
+        Dependency.new(name, external_source_info)
+      when /HEAD/
+        # @TODO: find a way to serialize from the Downloader the information
+        #   necessary to restore a head version.
+        Dependency.new(name, :head)
+      else
+        Dependency.new(name, version)
+      end
+    end
+
+    # Analyzes the {Lockfile} and detects any changes applied to the {Podfile}
+    # since the last installation.
+    #
+    # For each Pod, it detects one state among the following:
+    #
+    # - added: Pods that weren't present in the Podfile.
+    # - changed: Pods that were present in the Podfile but changed:
+    #   - Pods whose version is not compatible anymore with Podfile,
+    #   - Pods that changed their head or external options.
+    # - removed: Pods that were removed form the Podfile.
+    # - unchanged: Pods that are still compatible with Podfile.
+    #
+    # @TODO: detect changes for inline dependencies?
+    #
+    # @return [Hash{Symbol=>Array[Strings]}] A hash where pods are grouped
+    # by the state in which they are.
+    #
+    def detect_changes_with_podfile(podfile)
+      previous_podfile_deps = dependencies.map(&:name)
+      user_installed_pods   = pods_names.reject { |name| !previous_podfile_deps.include?(name) }
+      deps_to_install       = podfile.dependencies.dup
+
+      result = {}
+      result[:added]      = []
+      result[:changed]    = []
+      result[:removed]    = []
+      result[:unchanged]  = []
+
+      user_installed_pods.each do |pod_name|
+        dependency = deps_to_install.find { |d| d.name == pod_name }
+        deps_to_install.delete(dependency)
+        version = pods_versions[pod_name]
+        external_source = Dependency::ExternalSources.from_params(pod_name, external_sources[pod_name])
+
+        if dependency.nil?
+          result[:removed] << pod_name
+        elsif !dependency.match_version?(version) || dependency.external_source != external_source
+          result[:changed] << pod_name
+        else
+          result[:unchanged] << pod_name
+        end
+      end
+
+      deps_to_install.each do |dependency|
+        result[:added] << dependency.name
+      end
+      result
+    end
+
+    # @return [void] Writes the Lockfile to {#path}.
+    #
+    def write_to_disk(path)
+      File.open(path, 'w') {|f| f.write(to_yaml) }
+      defined_in_file = path
+    end
+
+    # @return [String] A string useful to represent the Lockfile in a message
+    #   presented to the user.
+    #
+    def to_s
+      "Podfile.lock"
+    end
+
+    # @return [String] The YAML representation of the Lockfile, used for
+    #   serialization.
+    #
+    def to_yaml
+      to_hash.to_yaml.gsub(/^--- ?\n/,"").gsub(/^([A-Z])/,"\n\\1")
+    end
+
+    # @return [Hash] The Hash representation of the Lockfile generated from
+    #   a given Podfile and the list of resolved Specifications.
+    #
+    def self.generate_hash_from_podfile(podfile, specs)
+      hash = {}
+
+      # Get list of [name, dependencies] pairs.
+      pod_and_deps = specs.map do |spec|
+        [spec.to_s, spec.dependencies.map(&:to_s).sort]
+      end.uniq
+
+      # Merge dependencies of iOS and OS X version of the same pod.
+      tmp = {}
+      pod_and_deps.each do |name, deps|
+        if tmp[name]
+          tmp[name].concat(deps).uniq!
+        else
+          tmp[name] = deps
+        end
+      end
+      pod_and_deps = tmp.sort_by(&:first).map do |name, deps|
+        deps.empty? ? name : { name => deps }
+      end
+      hash["PODS"] = pod_and_deps
+
+      hash["DEPENDENCIES"] = podfile.dependencies.map{ |d| d.to_s }.sort
+
+      external_sources = {}
+      deps = podfile.dependencies.select(&:external?).sort{ |d, other| d.name <=> other.name}
+      deps.each{ |d| external_sources[d.name] = d.external_source.params }
+      hash["EXTERNAL SOURCES"] = external_sources unless external_sources.empty?
+
+      checksums = {}
+      specs.select { |spec| !spec.defined_in_file.nil? }.each do |spec|
+        checksum = Digest::SHA1.hexdigest(File.read(spec.defined_in_file))
+        checksum = checksum.encode('UTF-8') if checksum.respond_to?(:encode)
+        checksums[spec.name] = checksum
+      end
+      hash["SPEC CHECKSUMS"] = checksums unless checksums.empty?
+      hash["COCOAPODS"] = VERSION
+      hash
+    end
+  end
+end
+

lib/cocoapods/podfile.rb

@@ -538,5 +538,9 @@ module Pod
 
     def validate!
     end
+
+    def to_s
+      "Podfile"
+    end
   end
 end

lib/cocoapods/project.rb

@@ -34,9 +34,14 @@ module Pod
       groups.find { |g| g.name == 'Pods' } || groups.new({ 'name' => 'Pods' })
     end
 
+    # Shortcut access to the `Local Pods' PBXGroup.
+    def local_pods
+      groups.find { |g| g.name == 'Local Pods' } || groups.new({ 'name' => 'Local Pods' })
+    end
+
     # Adds a group as child to the `Pods' group namespacing subspecs.
-    def add_spec_group(name)
-      groups = pods.groups
+    def add_spec_to_group(name, parent_group)
+      groups = parent_group.groups
       group = nil
       name.split('/').each do |name|
         group = groups.find { |g| g.name == name } || groups.new({ 'name' => name })

lib/cocoapods/resolver.rb

@@ -4,44 +4,169 @@ module Pod
   class Resolver
     include Config::Mixin
 
-    attr_reader :podfile, :sandbox
-    attr_accessor :cached_sets, :cached_sources
+    # @return [Bool] Whether the resolver should find the pods to install or
+    #   the pods to update.
+    #
+    attr_accessor :update_mode
 
-    def initialize(podfile, sandbox)
+    # @return [Bool] Whether the resolver should update the external specs
+    #   in the resolution process.
+    #
+    attr_accessor :update_external_specs
+
+    # @return [Podfile] The Podfile used by the resolver.
+    #
+    attr_reader :podfile
+
+    # @return [Lockfile] The Lockfile used by the resolver.
+    #
+    attr_reader :lockfile
+
+    # @return [Sandbox] The Sandbox used by the resolver to find external
+    #   dependencies.
+    #
+    attr_reader :sandbox
+
+    # @return [Array<Strings>] The name of the pods that have an
+    #   external source.
+    #
+    attr_reader :pods_from_external_sources
+
+    # @return [Array<Set>] A cache of the sets used to resolve the dependencies.
+    #
+    attr_reader :cached_sets
+
+    # @return [Source::Aggregate] A cache of the sources needed to find the
+    #   podspecs.
+    #
+    attr_reader :cached_sources
+
+    # @return [Hash{Podfile::TargetDefinition => Array<Specification>}]
+    #   Returns the resolved specifications grouped by target.
+    #
+    attr_reader :specs_by_target
+
+    def initialize(podfile, lockfile, sandbox)
       @podfile  = podfile
+      @lockfile = lockfile
       @sandbox  = sandbox
+      @update_external_specs = true
+
       @cached_sets = {}
       @cached_sources = Source::Aggregate.new
-      @log_indent = 0;
     end
 
+    # Identifies the specifications that should be installed according whether
+    #   the resolver is in update mode or not.
+    #
+    # @return [Hash{Podfile::TargetDefinition => Array<Specification>}] specs_by_target
+    #
     def resolve
-      @specs = {}
-      targets_and_specs = {}
+      @cached_specs = {}
+      @specs_by_target = {}
+      @pods_from_external_sources = []
+      @pods_to_lock = []
+      @log_indent = 0
+
+      if @lockfile
+        puts "\nFinding added, modified or removed dependencies:".green if config.verbose?
+        @pods_by_state = @lockfile.detect_changes_with_podfile(podfile)
+        if config.verbose?
+          @pods_by_state.each do |symbol, pod_names|
+            case symbol
+            when :added
+              mark = "A".green
+            when :changed
+              mark = "M".yellow
+            when :removed
+              mark = "R".red
+            when :unchanged
+              mark = "-"
+            end
+            pod_names.each do |pod_name|
+              puts "  #{mark} " << pod_name
+            end
+          end
+        end
+        @pods_to_lock = (lockfile.pods_names - @pods_by_state[:added] - @pods_by_state[:changed] - @pods_by_state[:removed]).uniq
+      end
 
       @podfile.target_definitions.values.each do |target_definition|
-        puts "\nResolving dependencies for target `#{target_definition.name}' (#{target_definition.platform})".green if config.verbose?
+        puts "\nResolving dependencies for target `#{target_definition.name}' (#{target_definition.platform}):".green if config.verbose?
         @loaded_specs = []
         find_dependency_specs(@podfile, target_definition.dependencies, target_definition)
-        targets_and_specs[target_definition] = @specs.values_at(*@loaded_specs).sort_by(&:name)
+        @specs_by_target[target_definition] = @cached_specs.values_at(*@loaded_specs).sort_by(&:name)
+      end
+
+      @cached_specs.values.sort_by(&:name)
+      @specs_by_target
     end
 
-      @specs.values.sort_by(&:name)
-      targets_and_specs
+    # @return [Array<Specification>] The specifications loaded by the resolver.
+    #
+    def specs
+      @cached_specs.values.uniq
+    end
+
+    # @return [Bool] Whether a pod should be installed/reinstalled.
+    #
+    def should_install?(name)
+      pods_to_install.include? name
+    end
+
+    # @return [Array<Strings>] The name of the pods that should be
+    #   installed/reinstalled.
+    #
+    def pods_to_install
+      unless @pods_to_install
+        if lockfile
+          @pods_to_install = specs.select do |spec|
+            spec.version != lockfile.pods_versions[spec.pod_name]
+          end.map(&:name)
+          if update_mode
+            @pods_to_install += specs.select do |spec|
+              spec.version.head? || pods_from_external_sources.include?(spec.pod_name)
+            end.map(&:name)
+          end
+          @pods_to_install += @pods_by_state[:added] + @pods_by_state[:changed]
+        else
+          @pods_to_install = specs.map(&:name)
+        end
+      end
+      @pods_to_install
+    end
+
+    # @return [Array<Strings>] The name of the pods that were installed
+    #   but don't have any dependency anymore. The name of the Pods are
+    #   stripped from subspecs.
+    #
+    def removed_pods
+      return [] unless lockfile
+      unless @removed_pods
+        previusly_installed = lockfile.pods_names.map { |pod_name| pod_name.split('/').first }
+        installed = specs.map { |spec| spec.name.split('/').first }
+        @removed_pods = previusly_installed - installed
+      end
+      @removed_pods
     end
 
     private
 
+    # @return [Set] The cached set for a given dependency.
+    #
     def find_cached_set(dependency, platform)
       set_name = dependency.name.split('/').first
       @cached_sets[set_name] ||= begin
         if dependency.specification
           Specification::Set::External.new(dependency.specification)
         elsif external_source = dependency.external_source
-          # The platform isn't actually being used by the LocalPod instance
-          # that's being used behind the scenes, but passing it anyways for
-          # completeness sake.
+          if update_mode && update_external_specs
+            # Always update external sources in update mode.
+            specification = external_source.specification_from_external(@sandbox, platform)
+          else
+            # Don't update external sources in install mode if not needed.
             specification = external_source.specification_from_sandbox(@sandbox, platform)
+          end
           set = Specification::Set::External.new(specification)
           if dependency.subspec_dependency?
             @cached_sets[dependency.top_level_spec_name] ||= set
@@ -53,29 +178,48 @@ module Pod
       end
     end
 
+    # Resolves the dependencies of a specification and stores them in @cached_specs
+    #
+    # @param [Specification] dependent_specification
+    # @param [Array<Dependency>] dependencies
+    # @param [TargetDefinition] target_definition
+    #
+    # @return [void]
+    #
     def find_dependency_specs(dependent_specification, dependencies, target_definition)
       @log_indent += 1
       dependencies.each do |dependency|
+        # Replace the dependency with a more specific one if the pod is already installed.
+        if !update_mode && @pods_to_lock.include?(dependency.name)
+          dependency = lockfile.dependency_for_installed_pod_named(dependency.name)
+        end
+
         puts '  ' * @log_indent + "- #{dependency}" if config.verbose?
         set = find_cached_set(dependency, target_definition.platform)
-        set.required_by(dependent_specification)
+        set.required_by(dependency, dependent_specification.to_s)
+
         # Ensure we don't resolve the same spec twice for one target
         unless @loaded_specs.include?(dependency.name)
           spec = set.specification_by_name(dependency.name)
+          @pods_from_external_sources << spec.pod_name if dependency.external?
           @loaded_specs << spec.name
-          @specs[spec.name] = spec
+          @cached_specs[spec.name] = spec
           # Configure the specification
           spec.activate_platform(target_definition.platform)
           spec.version.head = dependency.head?
           # And recursively load the dependencies of the spec.
           find_dependency_specs(spec, spec.dependencies, target_definition) if spec.dependencies
         end
-        validate_platform!(spec || @specs[dependency.name], target_definition)
+        validate_platform(spec || @cached_specs[dependency.name], target_definition)
       end
       @log_indent -= 1
     end
 
-    def validate_platform!(spec, target)
+    # Ensures that a spec is compatible with platform of a target.
+    #
+    # @raises If the spec is not supported by the target.
+    #
+    def validate_platform(spec, target)
       unless spec.available_platforms.any? { |platform| target.platform.supports?(platform) }
         raise Informative, "[!] The platform of the target `#{target.name}' (#{target.platform}) is not compatible with `#{spec}' which has a minimun requirement of #{spec.available_platforms.join(' - ')}.".red
       end

lib/cocoapods/specification.rb

@@ -174,6 +174,12 @@ module Pod
     end
     attr_writer :name
 
+    # @return [String] The name of the pod.
+    #
+    def pod_name
+      top_level_parent.name
+    end
+
     ### Attributes that return the first value defined in the chain
 
     def platform
@@ -387,14 +393,14 @@ module Pod
       # Remove this spec's name from the beginning of the name we’re looking for
       # and take the first component from the remainder, which is the spec we need
       # to find now.
-      remainder = name[self.name.size+1..-1].split('/')
-      subspec_name = remainder.shift
+      remainder = name[self.name.size+1..-1]
+      raise Informative, "Unable to find a specification named `#{name}' in `#{pod_name}'." unless remainder
+      subspec_name = remainder.split('/').shift
       subspec = subspecs.find { |s| s.name == "#{self.name}/#{subspec_name}" }
+      raise Informative, "Unable to find a specification named `#{name}' in `#{pod_name}'." unless subspec
       # If this was the last component in the name, then return the subspec,
       # otherwise we recursively keep calling subspec_by_name until we reach the
       # last one and return that
-
-      raise Informative, "Unable to find a subspec named `#{name}'." unless subspec
       remainder.empty? ? subspec : subspec.subspec_by_name(name)
     end
 
@@ -402,17 +408,9 @@ module Pod
       !source.nil? && !source[:local].nil?
     end
 
-    def local_path
-      Pathname.new(File.expand_path(source[:local]))
-    end
-
     def pod_destroot
-      if local?
-        local_path
-      else
       config.project_pods_root + top_level_parent.name
     end
-    end
 
     def self.pattern_list(patterns)
       if patterns.is_a?(Array) && (!defined?(Rake) || !patterns.is_a?(Rake::FileList))

lib/cocoapods/specification/set.rb

@@ -8,22 +8,18 @@ module Pod
       def initialize(pod_dir)
         @pod_dir = pod_dir
         @required_by = []
+        @dependencies = []
       end
 
-      def required_by(specification)
-        # Skip subspecs because the can't require a different version of the top level parent
-        return if !specification.podfile? && specification.top_level_parent.name == name
-
-        dependency = specification.dependency_by_top_level_spec_name(name)
-        # TODO we don’t actually do anything in our Version subclass. Maybe we should just remove that.
+      def required_by(dependency, dependent_name)
         unless @required_by.empty? || dependency.requirement.satisfied_by?(Gem::Version.new(required_version.to_s))
-          # TODO add graph that shows which dependencies led to this.
-          raise Informative, "#{specification} tries to activate `#{dependency}', " \
+          raise Informative, "#{dependent_name} tries to activate `#{dependency}', " \
                              "but already activated version `#{required_version}' " \
                              "by #{@required_by.to_sentence}."
         end
         @specification = nil
-        @required_by << specification
+        @required_by << dependent_name
+        @dependencies << dependency
       end
 
       def specification_by_name(name)
@@ -31,8 +27,8 @@ module Pod
       end
 
       def dependency
-        @required_by.inject(Dependency.new(name)) do |previous, spec|
-          previous.merge(spec.dependency_by_top_level_spec_name(name).to_top_level_spec_dependency)
+        @dependencies.inject(Dependency.new(name)) do |previous, dependency|
+          previous.merge(dependency.to_top_level_spec_dependency)
         end
       end
 
@@ -76,6 +72,7 @@ module Pod
         def initialize(specification)
           @specification = specification
           @required_by = []
+          @dependencies = []
         end
 
         def name
@@ -86,9 +83,9 @@ module Pod
           self.class === other && name == other.name
         end
 
-        def required_by(specification)
+        def required_by(dependency, dependent_name)
           before = @specification
-          super(specification)
+          super(dependency, dependent_name)
         ensure
           @specification = before
         end

lib/cocoapods/version.rb

-
-
 module Pod
   class Version < Gem::Version
+
+    # @returns A Version described by its #to_s method.
+    #
+    # @TODO The `from' part of the regexp should be remove before 1.0.0.
+    #
+    def self.from_string(string)
+      if string =~ /HEAD (based on|from) (.*)/
+        v = Version.new($2)
+        v.head = true
+        v
+      else
+        Version.new(string)
+      end
+    end
+
     attr_accessor :head
     alias_method :head?, :head
+
+    def to_s
+      head? ? "HEAD based on #{super}" : super
+    end
   end
 end
 

spec/functional/command/outdated_spec.rb

+require File.expand_path('../../../spec_helper', __FILE__)
+
+describe Pod::Command::Outdated do
+  extend SpecHelper::Command
+  extend SpecHelper::TemporaryDirectory
+  extend SpecHelper::TemporaryRepos
+
+  it "tells the user that no Podfile was found in the current working dir" do
+    exception = lambda { run_command('outdated','--no-update') }.should.raise Pod::Informative
+    exception.message.should.include "No `Podfile' found in the current working directory."
+  end
+
+  it "tells the user that no Lockfile was found in the current working dir" do
+    file = temporary_directory + 'Podfile'
+    File.open(file, 'w') {|f| f.write('platform :ios') }
+    Dir.chdir(temporary_directory) do
+      exception = lambda { run_command('outdated','--no-update') }.should.raise Pod::Informative
+      exception.message.should.include "No `Podfile.lock' found in the current working directory"
+    end
+  end
+end
+

spec/functional/command/update_spec.rb

+require File.expand_path('../../../spec_helper', __FILE__)
+
+describe Pod::Command::Update do
+  extend SpecHelper::Command
+  extend SpecHelper::TemporaryDirectory
+  extend SpecHelper::TemporaryRepos
+
+  it "tells the user that no Podfile was found in the current working dir" do
+    exception = lambda { run_command('update','--no-update') }.should.raise Pod::Informative
+    exception.message.should.include "No `Podfile' found in the current working directory."
+  end
+
+  it "tells the user that no Lockfile was found in the current working dir" do
+    file = temporary_directory + 'Podfile'
+    File.open(file, 'w') {|f| f.write('platform :ios') }
+    Dir.chdir(temporary_directory) do
+      exception = lambda { run_command('update','--no-update') }.should.raise Pod::Informative
+      exception.message.should.include "No `Podfile.lock' found in the current working directory"
+    end
+  end
+end
+

spec/unit/dependency_spec.rb

@@ -73,7 +73,7 @@ module Pod
       it "identifies itself as a `bleeding edge' dependency" do
         dependency = Dependency.new("cocoapods", :head)
         dependency.should.be.head
-        dependency.to_s.should == "cocoapods [HEAD]"
+        dependency.to_s.should == "cocoapods (HEAD)"
       end
 
       it "only supports the `:head' option on the last version of a pod" do
@@ -98,7 +98,7 @@ module Pod
         Downloader.stubs(:for_target).returns(stub_everything)
 
         pod = mock('LocaPod', :downloaded= => true)
-        sandbox = stub('Sandbox', :root => '', :installed_pod_named => pod)
+        sandbox = stub('Sandbox', :root => temporary_sandbox.root, :installed_pod_named => pod)
         @dependency.external_source.copy_external_source_into_sandbox(sandbox, Platform.ios)
       end
     end

spec/unit/installer_spec.rb

@@ -14,7 +14,10 @@ module Pod
           xcodeproj 'MyProject'
           pod 'JSONKit'
         end
-        @xcconfig = Installer.new(podfile).target_installers.first.xcconfig.to_hash
+
+        sandbox = Sandbox.new(fixture('integration'))
+        resolver = Resolver.new(podfile, nil, sandbox)
+        @xcconfig = Installer.new(resolver).target_installers.first.xcconfig.to_hash
       end
 
       it "sets the header search paths where installed Pod headers can be found" do
@@ -35,7 +38,10 @@ module Pod
         platform :osx
         pod 'ASIHTTPRequest'
       end
-      installer = Installer.new(podfile)
+
+      sandbox = Sandbox.new(fixture('integration'))
+      resolver = Resolver.new(podfile, nil, sandbox)
+      installer = Installer.new(resolver)
       pods = installer.specifications.map do |spec|
         LocalPod.new(spec, installer.sandbox, podfile.target_definitions[:default].platform)
       end
@@ -51,7 +57,8 @@ module Pod
           pod 'JSONKit'
         end
       end
-      installer = Installer.new(podfile)
+      resolver = Resolver.new(podfile, nil, Sandbox.new(fixture('integration')))
+      installer = Installer.new(resolver)
       installer.target_installers.map(&:target_definition).map(&:name).should == [:not_empty]
     end
 
@@ -61,7 +68,8 @@ module Pod
         platform :ios
         xcodeproj path, 'App Store' => :release
       end
-      installer = Installer.new(podfile)
+      resolver = Resolver.new(podfile, nil, Sandbox.new(fixture('integration')))
+      installer = Installer.new(resolver)
       installer.project.build_configurations.map(&:name).sort.should == ['App Store', 'Debug', 'Release', 'Test']
     end
 
@@ -70,7 +78,8 @@ module Pod
         platform :ios
         pod 'JSONKit', :head
       end
-      installer = Installer.new(podfile)
+      resolver = Resolver.new(podfile, nil, Sandbox.new(fixture('integration')))
+      installer = Installer.new(resolver)
       pod = installer.pods.first
 
       downloader = stub('Downloader')

spec/unit/local_pod_spec.rb

@@ -323,4 +323,57 @@ describe Pod::LocalPod do
       public_headers.should == %w{ UIKit.h }
     end
   end
+
+  describe "concerning a Pod with a local source" do
+    extend SpecHelper::TemporaryDirectory
+
+    before do
+      @local_path = temporary_directory + 'localBanana'
+      @sandbox = temporary_sandbox
+      @spec = fixture_spec('banana-lib/BananaLib.podspec')
+      @spec.source = {:local => @local_path}
+      @pod = Pod::LocalPod::LocalSourcedPod.new(@spec, @sandbox, Pod::Platform.new(:ios))
+    end
+
+    it "is marked as local" do
+      @pod.to_s.should.include? '[LOCAL]'
+    end
+
+    it "is marked as downloaded" do
+      @pod.downloaded?.should.be.true
+    end
+
+    it "correctly repports the root of the pod" do
+      @pod.root.should == @local_path
+    end
+
+    it "doesn't create the root" do
+      @pod.create
+      @local_path.exist?.should.be.false
+    end
+
+    before do
+      FileUtils.cp_r(fixture('banana-lib'), @local_path)
+    end
+
+    it "doesn't cleans the user files" do
+      useless_file = @local_path + 'useless.txt'
+      FileUtils.touch (useless_file)
+      @pod.root.should == @local_path
+      @pod.clean!
+      useless_file.exist?.should.be.true
+    end
+
+    it "doesn't implode" do
+      @pod.implode
+      @local_path.exist?.should.be.true
+    end
+
+    it "detects the files of the pod" do
+      @pod.source_files.map {|path| path.to_s.gsub(/.*tmp\//,'') }.sort.should == [
+        "localBanana/Classes/Banana.m",
+        "localBanana/Classes/Banana.h"
+      ].sort
+    end
+  end
 end

spec/unit/lockfile_spec.rb

+require File.expand_path('../../spec_helper', __FILE__)
+
+describe "Pod::Lockfile" do
+
+  describe "In general" do
+    extend SpecHelper::TemporaryDirectory
+
+    def sample
+      text = <<-LOCKFILE.strip_heredoc
+PODS:
+- BananaLib (1.0):
+  - monkey (< 1.0.9, ~> 1.0.1)
+- monkey (1.0.8)
+
+DEPENDENCIES:
+- BananaLib (~> 1.0)
+
+SPEC CHECKSUMS:
+  BananaLib: !binary |-
+    MjI2Y2RkMTJkMzBhMWU4ZWM4OGM1ZmRkZWU2MDcwZDg0YTI1MGZjMQ==
+
+COCOAPODS: #{Pod::VERSION}
+      LOCKFILE
+    end
+
+    def podfile
+      Pod::Podfile.new do
+        platform :ios
+        pod 'BananaLib', '~>1.0'
+      end
+    end
+
+    def specs
+      specs = [
+        Pod::Specification.from_file(fixture('banana-lib/BananaLib.podspec')),
+        Pod::Specification.new do |s|
+          s.name = "monkey"
+          s.version = "1.0.8"
+        end
+      ]
+      specs.each { |s| s.activate_platform(:ios) }
+      specs
+    end
+
+    def tmp_path
+      temporary_directory + 'Podfile.lock'
+    end
+
+    it "loads from a hash" do
+      lockfile = Pod::Lockfile.new(YAML.load(sample))
+      lockfile.to_hash.should == YAML.load(sample)
+    end
+
+    it "loads from a file" do
+      File.open(tmp_path, 'w') {|f| f.write(sample) }
+      lockfile = Pod::Lockfile.from_file(tmp_path)
+      lockfile.defined_in_file.should == tmp_path
+      lockfile.to_hash.should == YAML.load(sample)
+    end
+
+    it "can be generated from a Podfile and a list of Specifications" do
+      lockfile = Pod::Lockfile.generate(podfile, specs)
+      lockfile.to_hash.should == YAML.load(sample)
+    end
+
+    before do
+      @lockfile = Pod::Lockfile.generate(podfile, specs)
+    end
+
+    it "generates a valid YAML representation" do
+      YAML.load(@lockfile.to_yaml).should == YAML.load(sample)
+    end
+
+    it "generates a valid Dictionary representation" do
+      @lockfile.to_hash.should == YAML.load(sample)
+    end
+
+    it "returns the list of the installed pods" do
+      @lockfile.pods_names.should == %w| BananaLib monkey |
+    end
+
+    it "returns the versions of the installed pods" do
+      @lockfile.pods_versions.should == {
+        "BananaLib" => Pod::Version.new("1.0"),
+        "monkey" => Pod::Version.new("1.0.8")
+      }
+    end
+
+    it "serializes correctly `:head' dependencies" do
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BananaLib', :head
+      end
+      specs = [
+        Pod::Specification.new do |s|
+          s.name = "BananaLib"
+          s.version = "1.0"
+        end,
+        Pod::Specification.new do |s|
+          s.name = "monkey"
+          s.version = "1.0.8"
+        end
+      ]
+      specs.each { |s| s.activate_platform(:ios) }
+      lockfile = Pod::Lockfile.generate(podfile, specs)
+      lockfile.to_hash["DEPENDENCIES"][0].should == "BananaLib (HEAD)"
+    end
+
+    it "serializes correctly external dependencies" do
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BananaLib', { :git => "www.example.com", :tag => '1.0' }
+      end
+      specs = [
+        Pod::Specification.new do |s|
+          s.name = "BananaLib"
+          s.version = "1.0"
+        end,
+        Pod::Specification.new do |s|
+          s.name = "monkey"
+          s.version = "1.0.8"
+        end
+      ]
+      specs.each { |s| s.activate_platform(:ios) }
+      lockfile = Pod::Lockfile.generate(podfile, specs)
+      lockfile.to_hash["DEPENDENCIES"][0].should == "BananaLib (from `www.example.com', tag `1.0')"
+      lockfile.to_hash["EXTERNAL SOURCES"]["BananaLib"].should == { :git => "www.example.com", :tag => '1.0' }
+    end
+
+    it "creates a dependency from a string" do
+      d = @lockfile.dependency_from_string("BananaLib (1.0)")
+      d.name.should == "BananaLib"
+      d.requirement.should =~ Pod::Version.new("1.0")
+      d.head.should.be.nil
+      d.external_source.should.be.nil
+    end
+
+    it "creates a head dependency from a string" do
+      d = @lockfile.dependency_from_string("BananaLib (HEAD)")
+      d.name.should == "BananaLib"
+      d.requirement.should.be.none?
+      d.head.should.be.true
+      d.external_source.should.be.nil
+    end
+
+    it "creates an external dependency from a string" do
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BananaLib', { :git => "www.example.com", :tag => '1.0' }
+      end
+      lockfile = Pod::Lockfile.generate(podfile, [])
+      d = lockfile.dependency_from_string("BananaLib (from `www.example.com', tag `1.0')")
+      d.name.should == "BananaLib"
+      d.requirement.should.be.none?
+      d.external?.should.be.true
+      d.external_source.description.should == "from `www.example.com', tag `1.0'"
+    end
+  end
+
+  describe "Concerning initialization from a file" do
+    extend SpecHelper::TemporaryDirectory
+
+    it "returns nil if it can't find the initialization file" do
+      lockfile = Pod::Lockfile.from_file(temporary_directory + 'Podfile.lock_not_existing')
+      lockfile.should == nil
+    end
+  end
+
+  describe "Concerning the identification of changes in the Podfile" do
+    before do
+      @podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BlocksKit'
+        pod 'JSONKit'
+      end
+      @specs = [
+        Pod::Specification.new do |s|
+          s.name = "BlocksKit"
+          s.version = "1.0.0"
+        end,
+        Pod::Specification.new do |s|
+          s.name = "JSONKit"
+          s.version = "1.4"
+        end ]
+        @specs.each { |s| s.activate_platform(:ios) }
+        @lockfile = Pod::Lockfile.generate(@podfile, @specs)
+    end
+
+    it "detects an added Pod" do
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BlocksKit'
+        pod 'JSONKit'
+        pod 'TTTAttributedLabel'
+      end
+      @lockfile.detect_changes_with_podfile(podfile).should == {
+        :changed=>[],
+        :removed=>[],
+        :unchanged=>["BlocksKit", "JSONKit"],
+        :added=>["TTTAttributedLabel"]
+      }
+    end
+
+    it "detects an removed Pod" do
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BlocksKit'
+      end
+      @lockfile.detect_changes_with_podfile(podfile).should == {
+        :changed=>[],
+        :removed=>["JSONKit"],
+        :unchanged=>["BlocksKit"],
+        :added=>[]
+      }
+    end
+
+    it "detects Pods whose version changed" do
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BlocksKit'
+        pod 'JSONKit', "> 1.4"
+      end
+      @lockfile.detect_changes_with_podfile(podfile).should == {
+        :changed=>["JSONKit"],
+        :removed=>[],
+        :unchanged=>["BlocksKit"],
+        :added=>[]
+      }
+    end
+
+    it "it doesn't mark a changed Pods whose version changed but is still compatible with the Podfile" do
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BlocksKit'
+        pod 'JSONKit', "> 1.0"
+      end
+      @lockfile.detect_changes_with_podfile(podfile).should == {
+        :changed=>[],
+        :removed=>[],
+        :unchanged=>["BlocksKit", "JSONKit"],
+        :added=>[]
+      }
+    end
+
+    it "detects Pods whose external source changed" do
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BlocksKit'
+        pod 'JSONKit', :git => "example1.com"
+      end
+      @lockfile.detect_changes_with_podfile(podfile).should == {
+        :changed=>["JSONKit"],
+        :removed=>[],
+        :unchanged=>["BlocksKit"],
+        :added=>[]
+      }
+      @lockfile = Pod::Lockfile.generate(podfile, @specs)
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BlocksKit'
+        pod 'JSONKit', :git => "example2.com"
+      end
+      @lockfile.detect_changes_with_podfile(podfile).should == {
+        :changed=>["JSONKit"],
+        :removed=>[],
+        :unchanged=>["BlocksKit"],
+        :added=>[]
+      }
+    end
+
+    it "detects Pods whose head state changed" do
+      podfile = Pod::Podfile.new do
+        platform :ios
+        pod 'BlocksKit'
+        pod 'JSONKit', :head
+      end
+      @lockfile.detect_changes_with_podfile(podfile).should == {
+        :changed=>["JSONKit"],
+        :removed=>[],
+        :unchanged=>["BlocksKit"],
+        :added=>[]
+      }
+      @specs = [
+        Pod::Specification.new do |s|
+          s.name = "BlocksKit"
+          s.version = "1.0.0"
+        end,
+        Pod::Specification.new do |s|
+          s.name = "JSONKit"
+          s.version = "1.4"
+          s.version.head = true
+        end ]
+        @specs.each { |s| s.activate_platform(:ios) }
+        @lockfile = Pod::Lockfile.generate(podfile, @specs)
+        podfile = Pod::Podfile.new do
+          platform :ios
+          pod 'BlocksKit'
+          pod 'JSONKit'
+        end
+
+        @lockfile.detect_changes_with_podfile(podfile).should == {
+          :changed=>["JSONKit"],
+          :removed=>[],
+          :unchanged=>["BlocksKit"],
+          :added=>[]
+        }
+    end
+  end
+end

spec/unit/project_spec.rb

@@ -12,7 +12,7 @@ describe 'Pod::Project' do
   end
 
   it "adds a group to the `Pods' group" do
-    group = @project.add_spec_group('JSONKit')
+    group = @project.add_spec_to_group('JSONKit', @project.pods)
     @project.pods.child_references.should.include group.uuid
     find_object({
       'isa' => 'PBXGroup',
@@ -23,7 +23,7 @@ describe 'Pod::Project' do
   end
 
   it "namespaces subspecs in groups" do
-    group = @project.add_spec_group('JSONKit/Subspec')
+    group = @project.add_spec_to_group('JSONKit/Subspec', @project.pods)
     @project.pods.groups.find { |g| g.name == 'JSONKit' }.child_references.should.include group.uuid
     find_object({
       'isa' => 'PBXGroup',

spec/unit/resolver_spec.rb

@@ -10,7 +10,7 @@ module Pod
         pod 'BlocksKit'
         # pod 'ASIWebPageRequest'
       end
-      @resolver = Resolver.new(@podfile, stub('sandbox'))
+      @resolver = Resolver.new(@podfile, nil, stub('sandbox'))
     end
 
     it "holds the context state, such as cached specification sets" do
@@ -73,7 +73,7 @@ module Pod
         pod 'RestKit/Network'
         pod 'RestKit/ObjectMapping/XML'
       end
-      resolver = Resolver.new(@podfile, stub('sandbox'))
+      resolver = Resolver.new(@podfile, nil, stub('sandbox'))
       resolver.resolve.values.flatten.map(&:name).sort.should == %w{
         FileMD5Hash
         ISO8601DateFormatter
@@ -93,7 +93,7 @@ module Pod
         platform :ios
         pod 'RestKit'
       end
-      resolver = Resolver.new(@podfile, stub('sandbox'))
+      resolver = Resolver.new(@podfile, nil, stub('sandbox'))
       resolver.resolve.values.flatten.map(&:name).sort.should == %w{
         FileMD5Hash
         ISO8601DateFormatter
@@ -139,7 +139,7 @@ module Pod
           end
         end
       end
-      resolver = Resolver.new(@podfile, stub('sandbox'))
+      resolver = Resolver.new(@podfile, nil, stub('sandbox'))
       specs = resolver.resolve.values.flatten.map(&:name).sort
       specs.should.not.include 'RestKit/ObjectMapping/XML'
       specs.should == %w{
@@ -175,7 +175,7 @@ module Pod
         end
       end
       @podfile.dependencies.first.external_source.stubs(:specification_from_sandbox).returns(spec)
-      resolver = Resolver.new(@podfile, stub('sandbox'))
+      resolver = Resolver.new(@podfile, nil, stub('sandbox'))
       resolver.resolve.values.flatten.map(&:name).sort.should == %w{ MainSpec/FirstSubSpec MainSpec/FirstSubSpec/SecondSubSpec }
     end
 
@@ -185,10 +185,189 @@ module Pod
         pod 'FileMD5Hash'
         pod 'JSONKit', :head
       end
-      resolver = Resolver.new(podfile, stub('sandbox'))
+      resolver = Resolver.new(podfile, nil, stub('sandbox'))
       filemd5hash, jsonkit = resolver.resolve.values.first.sort_by(&:name)
       filemd5hash.version.should.not.be.head
       jsonkit.version.should.be.head
     end
+
+    it "accepts a nil lockfile" do
+      lambda { Resolver.new(@podfile, nil, stub('sandbox'))}.should.not.raise
+    end
+
+    it "raises if it finds two conflicting dependencies" do
+      podfile = Podfile.new do
+        platform :ios
+        pod 'JSONKit', "1.4"
+        pod 'JSONKit', "1.5pre"
+      end
+      resolver = Resolver.new(podfile, nil, stub('sandbox'))
+      lambda {resolver.resolve}.should.raise Pod::Informative
+    end
+
+    describe "Concerning Installation mode" do
+      before do
+        config.repos_dir = fixture('spec-repos')
+        @podfile = Podfile.new do
+          platform :ios
+          pod 'BlocksKit'
+          pod 'JSONKit'
+        end
+        @specs = [
+          Pod::Specification.new do |s|
+            s.name = "BlocksKit"
+            s.version = "1.0.0"
+          end,
+          Pod::Specification.new do |s|
+            s.name = "JSONKit"
+            s.version = "1.4"
+          end ]
+        @specs.each { |s| s.activate_platform(:ios) }
+        @lockfile = Lockfile.generate(@podfile, @specs)
+        @resolver = Resolver.new(@podfile, @lockfile, stub('sandbox'))
+      end
+
+      it "doesn't install pods still compatible with the Podfile" do
+        @resolver.resolve
+        @resolver.should_install?("BlocksKit").should.be.false
+        @resolver.should_install?("JSONKit").should.be.false
+      end
+
+      it "doesn't update the version of pods still compatible with the Podfile" do
+        installed = @resolver.resolve.values.flatten.map(&:to_s)
+        installed.should.include? "JSONKit (1.4)"
+      end
+
+      it "doesn't include pods removed from the Podfile" do
+        podfile = Podfile.new { platform :ios; pod 'JSONKit' }
+        @resolver = Resolver.new(podfile, @lockfile, stub('sandbox'))
+        @resolver.resolve.values.flatten.map(&:name).should == %w{ JSONKit }
+      end
+
+      it "reinstalls pods updated in the Podfile" do
+        podfile = Podfile.new do
+          platform :ios
+          pod 'JSONKit', '1.5pre'
+          pod 'BlocksKit'
+        end
+        @resolver = Resolver.new(podfile, @lockfile, stub('sandbox'))
+        installed = @resolver.resolve.values.flatten.map(&:to_s)
+        installed.should.include? "BlocksKit (1.0.0)"
+        installed.should.include? "JSONKit (1.5pre)"
+      end
+
+      it "installs pods added to the Podfile" do
+        podfile = Podfile.new do
+          platform :ios
+          pod 'JSONKit'
+          pod 'BlocksKit'
+          pod 'libPusher'
+        end
+        @resolver = Resolver.new(podfile, @lockfile, stub('sandbox'))
+        installed = @resolver.resolve.values.flatten.map(&:to_s)
+        installed.should.include? "libPusher (1.3)"
+      end
+
+      it "handles head pods" do
+        podfile = Podfile.new do
+          platform :ios
+          pod 'JSONKit', :head   # Existing pod switched to head mode
+          pod 'libPusher', :head # New pod
+        end
+        @resolver = Resolver.new(podfile, @lockfile, stub('sandbox'))
+        @resolver.resolve
+        @resolver.should_install?("JSONKit").should.be.true
+        @resolver.should_install?("libPusher").should.be.true
+      end
+
+      it "handles pods from external dependencies" do
+        podfile = Podfile.new do
+          platform :ios
+          pod 'libPusher', :git => 'GIT-URL'
+        end
+        spec = Spec.new do |s|
+          s.name         = 'libPusher'
+          s.version      = '1.3'
+        end
+        podfile.dependencies.first.external_source.stubs(:specification_from_sandbox).returns(spec)
+        @resolver = Resolver.new(podfile, @lockfile, stub('sandbox'))
+        @resolver.resolve
+        @resolver.should_install?("JSONKit").should.be.false
+      end
+    end
+
+    describe "Concerning Update mode" do
+      before do
+        config.repos_dir = fixture('spec-repos')
+        @podfile = Podfile.new do
+          platform :ios
+          pod 'BlocksKit'
+          pod 'JSONKit'
+          pod 'libPusher'
+        end
+        @specs = [
+          Pod::Specification.new do |s|
+            s.name = "libPusher"
+            s.version = "1.3"
+          end,
+          Pod::Specification.new do |s|
+            s.name = "JSONKit"
+            s.version = "1.4"
+          end ]
+        @specs.each { |s| s.activate_platform(:ios) }
+        @lockfile = Lockfile.generate(@podfile, @specs)
+        @resolver = Resolver.new(@podfile, @lockfile, stub('sandbox'))
+        @resolver.update_mode = true
+      end
+
+      it "identifies the pods that can be updated" do
+        installed = @resolver.resolve.values.flatten.map(&:to_s)
+        installed.should.include? "JSONKit (1.5pre)"
+        @resolver.should_install?("JSONKit").should.be.true
+      end
+
+      it "respects the constraints of the podfile" do
+        podfile = Podfile.new do
+          platform :ios
+          pod 'BlocksKit'
+          pod 'JSONKit', '1.4'
+        end
+        @resolver = Resolver.new(podfile, @lockfile, stub('sandbox'))
+        @resolver.update_mode = true
+        installed = @resolver.resolve.values.flatten.map(&:to_s)
+        installed.should.include? "JSONKit (1.4)"
+        @resolver.should_install?("JSONKit").should.be.false
+      end
+
+      it "installs new pods" do
+        installed = @resolver.resolve.values.flatten.map(&:to_s)
+        installed.join(' ').should.include?('BlocksKit')
+        @resolver.should_install?("BlocksKit").should.be.true
+      end
+
+      it "it always suggests to update pods in head mode" do
+        podfile = Podfile.new do
+          platform :ios
+          pod 'libPusher', :head
+        end
+        @resolver = Resolver.new(podfile, @lockfile, stub('sandbox'))
+        @resolver.update_mode = true
+        @resolver.resolve
+        @resolver.should_install?("libPusher").should.be.true
+      end
+
+      # TODO: stub the specification resolution for the sandbox
+      xit "it always suggests to update pods from external sources" do
+        podfile = Podfile.new do
+          platform :ios
+          pod 'libPusher', :git => "example.com"
+        end
+        @resolver = Resolver.new(podfile, @lockfile, stub('sandbox'))
+        @resolver.update_mode = true
+        @resolver.resolve
+        @resolver.should_install?("libPusher").should.be.true
+      end
+    end
+
   end
 end

spec/unit/specification/set_spec.rb

@@ -14,23 +14,23 @@ describe "Pod::Specification::Set" do
   end
 
   it "checks if the dependency of the specification is compatible with existing requirements" do
-    @set.required_by(Pod::Spec.new { |s| s.dependency 'CocoaLumberjack', '1.2' })
-    @set.required_by(Pod::Spec.new { |s| s.dependency 'CocoaLumberjack', '< 1.2.1' })
-    @set.required_by(Pod::Spec.new { |s| s.dependency 'CocoaLumberjack', '> 1.1' })
-    @set.required_by(Pod::Spec.new { |s| s.dependency 'CocoaLumberjack', '~> 1.2.0' })
-    @set.required_by(Pod::Spec.new { |s| s.dependency 'CocoaLumberjack' })
+    @set.required_by(Pod::Dependency.new('CocoaLumberjack', '1.2'), 'Spec')
+    @set.required_by(Pod::Dependency.new('CocoaLumberjack', '< 1.2.1'), 'Spec')
+    @set.required_by(Pod::Dependency.new('CocoaLumberjack', '> 1.1'), 'Spec')
+    @set.required_by(Pod::Dependency.new('CocoaLumberjack', '~> 1.2.0'), 'Spec')
+    @set.required_by(Pod::Dependency.new('CocoaLumberjack'), 'Spec')
     lambda {
-      @set.required_by(Pod::Spec.new { |s| s.dependency 'CocoaLumberjack', '< 1.0' })
+      @set.required_by(Pod::Dependency.new('CocoaLumberjack', '< 1.0' ), 'Spec')
     }.should.raise Pod::Informative
   end
 
   it "raises if the required version doesn't exist" do
-    @set.required_by(Pod::Spec.new { |s| s.dependency 'CocoaLumberjack', '< 1.0' })
+    @set.required_by(Pod::Dependency.new('CocoaLumberjack', '< 1.0'), 'Spec')
     lambda { @set.required_version }.should.raise Pod::Informative
   end
 
   before do
-    @set.required_by(Pod::Spec.new { |s| s.dependency 'CocoaLumberjack', '< 1.2.1' })
+    @set.required_by(Pod::Dependency.new('CocoaLumberjack', '< 1.2.1'), 'Spec')
   end
 
   it "returns the version required for the dependency" do
@@ -49,4 +49,9 @@ describe "Pod::Specification::Set" do
     `touch #{fixture('spec-repos/master/CocoaLumberjack/.DS_Store')}`
     lambda { @set.versions }.should.not.raise
   end
+
+  it "raises if a version is incompatible with the activated version" do
+    spec = Pod::Dependency.new('CocoaLumberjack', '1.2.1')
+    lambda { @set.required_by(spec, 'Spec') }.should.raise Pod::Informative
+  end
 end

spec/unit/specification_spec.rb

@@ -230,6 +230,12 @@ describe "A Pod::Specification, in general," do
     @spec.platform = :ios
     @spec.activate_platform(:ios).should == @spec
   end
+
+  it "it handles local sources" do
+    @spec.activate_platform(:ios)
+    @spec.source = {:local => '/tmp/local/path'}
+    @spec.local?.should.be.true
+  end
 end
 
 describe "A Pod::Specification, hierarchy" do
@@ -479,7 +485,7 @@ describe "A Pod::Specification with :local source" do
   end
 
   it "it returns the expanded local path" do
-    @spec.local_path.should == fixture("integration/JSONKit")
+    @spec.source.should == {:local => fixture("integration/JSONKit")}
   end
 end
 

spec/unit/version_spec.rb

@@ -8,5 +8,21 @@ module Pod
       version.head = true
       version.should.be.head
     end
+
+    it "serializes to and from a string" do
+      version = Version.from_string('1.2.3')
+      version.to_s.should == '1.2.3'
+      version.should.not.be.head
+
+      version = Version.from_string('HEAD based on 1.2.3')
+      version.should.be.head
+      version.to_s.should == 'HEAD based on 1.2.3'
+    end
+
+    it "supports the previous way that a HEAD version was described" do
+      version = Version.from_string('HEAD from 1.2.3')
+      version.should.be.head
+      version.to_s.should == 'HEAD based on 1.2.3'
+    end
   end
 end