[Command] Raise when using git < 1.8.5

CHANGELOG.md

@@ -37,6 +37,10 @@ To install release candidates run `[sudo] gem install cocoapods --pre`
 * Fixed code signing issue causing lint failure on macOS.  
   [Paul Cantrell](https://github.com/pcantrell)
   [#5645](https://github.com/CocoaPods/CocoaPods/issues/5645)
+* Raise an exception when using a git version prior to 1.8.5.  
+  [Danielle Tomlinson](https://github.com/dantoml)
+  [#6078](https://github.com/CocoaPods/CocoaPods/issues/6078)
+
 
 ## 1.2.0.beta.1 (2016-10-28)
 

lib/cocoapods/command.rb

@@ -45,6 +45,8 @@ module Pod
 
     def self.run(argv)
       help! 'You cannot run CocoaPods as root.' if Process.uid == 0
+
+      verify_minimum_git_version!
       verify_xcode_license_approved!
 
       super(argv)
@@ -105,6 +107,28 @@ module Pod
 
     private
 
+    # Returns a new {Gem::Version} based on the systems `git` version.
+    #
+    # @return [Gem::Version]
+    #
+    def self.git_version
+      raw_version = Executable.capture_command('git', ['--version']).first
+      match = raw_version.scan(/\d+\.\d+\.\d+/).first
+      Gem::Version.new(match)
+    end
+
+    # Checks that the git version is at least 1.8.5
+    #
+    # @raise If the git version is older than 1.8.5
+    #
+    # @return [void]
+    #
+    def self.verify_minimum_git_version!
+      if git_version < Gem::Version.new('1.8.5')
+        raise Informative, 'You need at least git version 1.8.5 to use CocoaPods'
+      end
+    end
+
     # Returns a new {Installer} parametrized from the {Config}.
     #
     # @return [Installer]

spec/unit/command_spec.rb

@@ -19,5 +19,50 @@ module Pod
       Command.parse(%w(init            )).should.be.instance_of Command::Init
       Command.parse(%w(env             )).should.be.instance_of Command::Env
     end
+
+    describe 'git version validation' do
+      valid_git_versions = [
+        Gem::Version.new('1.8.5'),
+        Gem::Version.new('2.10.2'),
+        Gem::Version.new('2.8.4'),
+      ]
+
+      invalid_git_versions = [
+        Gem::Version.new('1.7.4'),
+        Gem::Version.new('0.2.9'),
+      ]
+
+      valid_git_versions.each do |version|
+        it "does not raise an error for version #{version}" do
+          Command.expects(:git_version).returns(version)
+          lambda { Command.verify_minimum_git_version! }.should.not.raise
+        end
+      end
+
+      invalid_git_versions.each do |version|
+        it "raises an error for version #{version}" do
+          Command.expects(:git_version).returns(version)
+          lambda { Command.verify_minimum_git_version! }.should.raise Informative
+        end
+      end
+    end
+
+    describe 'git version extraction' do
+      git_versions = [
+        ['git version 1.2.4', Gem::Version.new('1.2.4')],
+        ['git version 1.4.5', Gem::Version.new('1.4.5')],
+        ['git version 1.7.4', Gem::Version.new('1.7.4')],
+        ['git version 2.10.2', Gem::Version.new('2.10.2')],
+        ['git version 2.10.2', Gem::Version.new('2.10.2')],
+        ['git version 2.8.4 (Apple Git-73)', Gem::Version.new('2.8.4')],
+      ]
+
+      git_versions.each do |pair|
+        it "returns the correct version for #{pair[0]}" do
+          Executable.expects(:capture_command).with('git', ['--version']).returns([pair[0]])
+          Command.git_version.should == pair[1]
+        end
+      end
+    end
   end
 end