Fix another bug with the file annotations cache when validating code ownership with --diff (#64)

* write failing test

* fix failing test

* Bump version

Author: Alex Evanczuk

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    code_ownership (1.32.16)
+    code_ownership (1.32.17)
       code_teams (~> 1.0)
       packs
       sorbet-runtime

code_ownership.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |spec|
   spec.name          = 'code_ownership'
-  spec.version       = '1.32.16'
+  spec.version       = '1.32.17'
   spec.authors       = ['Gusto Engineers']
   spec.email         = ['[email protected]']
   spec.summary       = 'A gem to help engineering teams declare ownership of code'

lib/code_ownership/private/ownership_mappers/file_annotations.rb

@@ -49,6 +49,7 @@ def globs_to_owner(files)
         def update_cache(cache, files)
           # We map files to nil owners so that files whose annotation have been removed will be properly
           # overwritten (i.e. removed) from the cache.
+          fileset = Set.new(files)
           updated_cache_for_files = globs_to_owner(files)
           cache.merge!(updated_cache_for_files)
 
@@ -57,7 +58,8 @@ def update_cache(cache, files)
             !Private.file_tracked?(file) ||
             # If a file no longer has a file annotation (i.e. `globs_to_owner` doesn't map it)
             # it should be removed from the cache
-            !updated_cache_for_files.key?(file)
+            # We make sure to only apply this to the input files since otherwise `updated_cache_for_files.key?(file)` would always return `false` when files == []
+            (fileset.include?(file) && !updated_cache_for_files.key?(file))
           end
 
           invalid_files.each do |invalid_file|

spec/lib/code_ownership/private/validations/github_codeowners_up_to_date_spec.rb

@@ -629,6 +629,44 @@ module CodeOwnership
             end
           end
         end
+
+        context 'validating codeowners using --diff in an application with a CODEOWNERS file' do
+          before do
+            write_configuration
+
+            write_file('packs/my_pack/had_annotation_file.rb', <<~CONTENTS)
+              # @team Bar
+            CONTENTS
+
+            write_file('config/teams/bar.yml', <<~CONTENTS)
+              name: Bar
+              github:
+                team: '@MyOrg/bar-team'
+            CONTENTS
+          end
+
+          it 'prints out the diff' do
+            FileUtils.mkdir('.github')
+            codeowners_path.write <<~CODEOWNERS
+              # STOP! - DO NOT EDIT THIS FILE MANUALLY
+              # This file was automatically generated by "bin/codeownership validate".
+              #
+              # CODEOWNERS is used for GitHub to suggest code/file owners to various GitHub
+              # teams. This is useful when developers create Pull Requests since the
+              # code/file owner is notified. Reference GitHub docs for more details:
+              # https://help.github.com/en/articles/about-code-owners
+
+              # Annotations at the top of file
+              /packs/my_pack/had_annotation_file.rb @MyOrg/bar-team
+
+              # Team YML ownership
+              /config/teams/bar.yml @MyOrg/bar-team
+            CODEOWNERS
+
+            expect_any_instance_of(codeowners_validation).to_not receive(:`) # rubocop:disable RSpec/AnyInstance
+            expect { CodeOwnership.validate!(autocorrect: false, files: []) }.to_not raise_error
+          end
+        end
       end
 
       context 'code_ownership.yml has skip_codeowners_validation set' do