[Podfile] Add validations in an attempt to catch issues common issue when…

[Podfile] Add validations in an attempt to catch issues common issue when specifying the dependencies for a project

CHANGELOG.md

@@ -54,6 +54,11 @@ To install release candidates run `[sudo] gem install cocoapods --pre`
 * Cache globbing in `PathList` to speed up `pod install`.
   [Vincent Isambart](https://github.com/vincentisambart)
 
+* CocoaPods will validate your podfile and try to identify problems 
+  and conflicts in how you've specified the dependencies
+  [Hugo Tunius](https://github.com/k0nserv)
+  [#995](https://github.com/CocoaPods/CocoaPods/issues/995)
+
 ##### Bug Fixes
 
 * Added recursive support to the public headers of vendored frameworks

lib/cocoapods/installer.rb

@@ -34,6 +34,7 @@ module Pod
     autoload :PostInstallHooksContext,  'cocoapods/installer/post_install_hooks_context'
     autoload :PreInstallHooksContext,   'cocoapods/installer/pre_install_hooks_context'
     autoload :Migrator,                 'cocoapods/installer/migrator'
+    autoload :PodfileValidator,         'cocoapods/installer/podfile_validator'
     autoload :PodSourceInstaller,       'cocoapods/installer/pod_source_installer'
     autoload :PodSourcePreparer,        'cocoapods/installer/pod_source_preparer'
     autoload :PodTargetInstaller,       'cocoapods/installer/target_installer/pod_target_installer'

lib/cocoapods/installer/analyzer.rb

@@ -52,6 +52,7 @@ module Pod
       # @return [AnalysisResult]
       #
       def analyze(allow_fetches = true)
+        validate_podfile!
         validate_lockfile_version!
         @result = AnalysisResult.new
         compute_target_platforms
@@ -143,6 +144,15 @@ module Pod
 
       private
 
+      def validate_podfile!
+        validator = Installer::PodfileValidator.new(podfile)
+        validator.validate
+
+        unless validator.valid?
+          raise Informative, validator.message
+        end
+      end
+
       # @!group Analysis steps
 
       # @note   The warning about the version of the Lockfile doesn't use the

lib/cocoapods/installer/podfile_validator.rb

+module Pod
+  class Installer
+    # Validate the podfile before installing to catch errors and
+    # problems
+    #
+    class PodfileValidator
+      # @return [Podfile] The podfile being validated
+      #
+      attr_reader :podfile
+
+      # @return [Array<String>] any errors that have occured during the validation
+      #
+      attr_reader :errors
+
+      # Initialize a new instance
+      # @param [Podfile] podfile
+      #        The podfile to validate
+      #
+      def initialize(podfile)
+        @podfile = podfile
+        @errors = []
+        @validated = false
+      end
+
+      # Validate the podfile
+      # Errors are added to the errors array
+      #
+      def validate
+        validate_pod_directives
+
+        @validated = true
+      end
+
+      # Wether the podfile is valid is not
+      # NOTE: Will execute `validate` if the podfile
+      # has not yet been validated
+      #
+      def valid?
+        validate unless @validated
+
+        @validated && errors.size == 0
+      end
+
+      # A message describing any errors in the
+      # validation
+      #
+      def message
+        errors.join("\n")
+      end
+
+      private
+
+      def add_error(error)
+        errors << error
+      end
+
+      def validate_pod_directives
+        dependencies = podfile.target_definitions.flat_map do |_, target|
+          target.dependencies
+        end.uniq
+
+        dependencies.each do |dependency|
+          validate_conflicting_external_sources!(dependency)
+        end
+      end
+
+      def validate_conflicting_external_sources!(dependency)
+        external_source = dependency.external_source
+        return false if external_source.nil?
+
+        available_downloaders = Downloader.downloader_class_by_key.keys
+        specified_downloaders = external_source.select { |key| available_downloaders.include?(key) }
+        if specified_downloaders.size > 1
+          add_error "The dependency `#{dependency.name}` specifies more than one download strategy(#{specified_downloaders.keys.join(',')})." \
+            'Only one is allowed'
+        end
+
+        pod_spec_or_path = external_source[:podspec].present? || external_source[:path].present?
+        if pod_spec_or_path && specified_downloaders.size > 0
+          add_error "The dependency `#{dependency.name}` specifies `podspec` or `path` in combination with other" \
+            ' download strategies. This is not allowed'
+        end
+      end
+    end
+  end
+end

spec/unit/installer/podfile_validator_spec.rb

+require File.expand_path('../../../spec_helper', __FILE__)
+
+module Pod
+  describe Installer::PodfileValidator do
+    describe 'podspec/path in combination with other download strategies' do
+      it 'validates that podspec is not used in combination with other download strategies' do
+        podfile = Pod::Podfile.new do
+          pod 'JSONKit', :podspec => 'https://raw.githubusercontent.com/CocoaPods/Specs/master/Specs/JSONKit/1.5pre/JSONKit.podspec.json',
+                         :git => 'git@github.com:johnezang/JSONKit.git'
+        end
+
+        validator = Installer::PodfileValidator.new(podfile)
+        validator.validate
+
+        validator.valid?.should.be.false
+        validator.errors.size.should == 1
+        validator.errors[0].should.match /The dependency `JSONKit` specifies `podspec` or `path`/
+      end
+
+      it 'validates that path is not used in combination with other download strategies' do
+        podfile = Pod::Podfile.new do
+          pod 'JSONKit', :path => './JSONKit/1.5pre/JSONKit.podspec.json',
+                         :git => 'git@github.com:johnezang/JSONKit.git'
+        end
+
+        validator = Installer::PodfileValidator.new(podfile)
+        validator.validate
+
+        validator.valid?.should.be.false
+        validator.errors.size.should == 1
+        validator.errors[0].should.match /The dependency `JSONKit` specifies `podspec` or `path`/
+      end
+
+      it 'validates when calling `valid?` before calling `validate`' do
+        podfile = Pod::Podfile.new do
+          pod 'JSONKit', :path => './JSONKit/1.5pre/JSONKit.podspec.json',
+                         :git => 'git@github.com:johnezang/JSONKit.git'
+        end
+
+        validator = Installer::PodfileValidator.new(podfile)
+        validator.valid?
+
+        validator.valid?.should.be.false
+      end
+    end
+
+    describe 'multiple download strategies' do
+      it 'validates that only one download strategy is specified' do
+        podfile = Pod::Podfile.new do
+          pod 'JSONKit', :svn => 'svn.example.com/JSONKit',
+                         :git => 'git@github.com:johnezang/JSONKit.git'
+        end
+        validator = Installer::PodfileValidator.new(podfile)
+        validator.validate
+
+        validator.valid?.should.be.false
+        validator.errors.size.should == 1
+        validator.errors[0].should.match /The dependency `JSONKit` specifies more than one/
+      end
+    end
+  end
+end