[Fix rubocop#9803] Fix Bundler/GemVersion cop not respecting git tags

Closes rubocop#9803

changelog/fix_gem_version_not_respecting_tags.md

@@ -0,0 +1 @@
+* [#9803](https://github.com/rubocop/rubocop/pull/9803): Fix `Bundler/GemVersion` cop not respecting git tags. ([@tejasbubane][])

lib/rubocop/cop/bundler/gem_version.rb

@@ -45,6 +45,21 @@ class GemVersion < Base
           (send nil? :gem <(str #version_specification?) ...>)
         PATTERN
 
+        # @!method with_git_ref?(node)
+        def_node_matcher :with_git_ref?, <<~PATTERN
+          (send nil? :gem <(hash <#git? #tag_ref? ...>) ...>)
+        PATTERN
+
+        # @!method tag_ref?(node)
+        def_node_matcher :tag_ref?, <<~PATTERN
+          (pair (sym {:tag :ref}) (str _))
+        PATTERN
+
+        # @!method git?(node)
+        def_node_matcher :git?, <<~PATTERN
+          (pair (sym {:git :github :bitbucket}) (str _))
+        PATTERN
+
         def on_send(node)
           return unless gem_declaration?(node)
           return if allowed_gem?(node)
@@ -78,8 +93,15 @@ def message(range)
         end
 
         def offense?(node)
-          (required_style? && !includes_version_specification?(node)) ||
-            (forbidden_style? && includes_version_specification?(node))
+          required_offense?(node) || forbidden_offense?(node)
+        end
+
+        def required_offense?(node)
+          required_style? && !includes_version_specification?(node) && !with_git_ref?(node)
+        end
+
+        def forbidden_offense?(node)
+          forbidden_style? && includes_version_specification?(node)
         end
 
         def forbidden_style?

spec/rubocop/cop/bundler/gem_version_spec.rb

@@ -15,6 +15,8 @@
         ^^^^^^^^^^^^^ Gem version specification is required.
         gem 'rubocop', require: false
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Gem version specification is required.
+        gem 'rubocop', tag: '1.2.0'
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Gem version specification is required.
       RUBY
     end
 
@@ -24,6 +26,9 @@
         gem 'rubocop', '~> 1'
         gem 'rubocop', '~> 1.12', require: false
         gem 'rubocop', '>= 1.5.0', '< 1.10.0', git: 'https://github.com/rubocop/rubocop'
+        gem 'rubocop', github: 'rubocop/rubocop', tag: 'v1'
+        gem 'rubocop', git: 'https://github.com/rubocop/rubocop', ref: 'b3f37bc7f'
+        gem 'foobar', bitbucket: 'foo/bar', tag: 'v1'
       RUBY
     end
 
@@ -67,5 +72,13 @@
         gem 'rspec', '~> 3.10'
       RUBY
     end
+
+    it 'does not flag gems using git source with tag or ref' do
+      expect_no_offenses(<<~RUBY)
+        gem 'rubocop', github: 'rubocop/rubocop', tag: 'v1'
+        gem 'rubocop', git: 'https://github.com/rubocop/rubocop', ref: 'b3f37bc7f'
+        gem 'foobar', bitbucket: 'foo/bar', tag: 'v1'
+      RUBY
+    end
   end
 end