Merge branch '29541-fix-github-importer-deleted-fork' into 'master'

Fix GitHub importer for PRs of deleted forked repositories

Closes #29541

See merge request !9992

changelogs/unreleased/29541-fix-github-importer-deleted-fork.yml

+---
+title: Fix GitHub Importer for PRs of deleted forked repositories
+merge_request: 9992
+author:

lib/gitlab/github_import/branch_formatter.rb

@@ -11,6 +11,14 @@ module Gitlab
         sha.present? && ref.present?
       end
 
+      def user
+        raw_data.user&.login || 'unknown'
+      end
+
+      def short_sha
+        Commit.truncate_sha(sha)
+      end
+
       private
 
       def branch_exists?

lib/gitlab/github_import/pull_request_formatter.rb

 module Gitlab
   module GithubImport
     class PullRequestFormatter < IssuableFormatter
-      delegate :exists?, :project, :ref, :repo, :sha, to: :source_branch, prefix: true
-      delegate :exists?, :project, :ref, :repo, :sha, to: :target_branch, prefix: true
+      delegate :user, :project, :ref, :repo, :sha, to: :source_branch, prefix: true
+      delegate :user, :exists?, :project, :ref, :repo, :sha, :short_sha, to: :target_branch, prefix: true
 
       def attributes
         {
@@ -37,13 +37,20 @@ module Gitlab
       end
 
       def source_branch_name
-        @source_branch_name ||= begin
-          if cross_project?
-            "pull/#{number}/#{source_branch_repo.full_name}/#{source_branch_ref}"
+        @source_branch_name ||=
+          if cross_project? || !source_branch_exists?
+            source_branch_name_prefixed
           else
-            source_branch_exists? ? source_branch_ref : "pull/#{number}/#{source_branch_ref}"
+            source_branch_ref
           end
       end
+
+      def source_branch_name_prefixed
+        "gh-#{target_branch_short_sha}/#{number}/#{source_branch_user}/#{source_branch_ref}"
+      end
+
+      def source_branch_exists?
+        !cross_project? && source_branch.exists?
       end
 
       def target_branch
@@ -51,13 +58,17 @@ module Gitlab
       end
 
       def target_branch_name
-        @target_branch_name ||= begin
-          target_branch_exists? ? target_branch_ref : "pull/#{number}/#{target_branch_ref}"
+        @target_branch_name ||= target_branch_exists? ? target_branch_ref : target_branch_name_prefixed
       end
+
+      def target_branch_name_prefixed
+        "gl-#{target_branch_short_sha}/#{number}/#{target_branch_user}/#{target_branch_ref}"
       end
 
       def cross_project?
-        source_branch.repo.id != target_branch.repo.id
+        return true if source_branch_repo.nil?
+
+        source_branch_repo.id != target_branch_repo.id
       end
 
       def opened?

spec/lib/gitlab/github_import/importer_spec.rb

@@ -215,9 +215,9 @@ describe Gitlab::GithubImport::Importer, lib: true do
   let(:updated_at) { DateTime.strptime('2011-01-27T19:01:12Z') }
   let(:repository) { double(id: 1, fork: false) }
   let(:source_sha) { create(:commit, project: project).id }
-  let(:source_branch) { double(ref: 'branch-merged', repo: repository, sha: source_sha) }
+  let(:source_branch) { double(ref: 'branch-merged', repo: repository, sha: source_sha, user: octocat) }
   let(:target_sha) { create(:commit, project: project, git_commit: RepoHelpers.another_sample_commit).id }
-  let(:target_branch) { double(ref: 'master', repo: repository, sha: target_sha) }
+  let(:target_branch) { double(ref: 'master', repo: repository, sha: target_sha, user: octocat) }
   let(:pull_request) do
     double(
       number: 1347,

spec/lib/gitlab/github_import/pull_request_formatter_spec.rb

@@ -4,15 +4,18 @@ describe Gitlab::GithubImport::PullRequestFormatter, lib: true do
   let(:client) { double }
   let(:project) { create(:project, :repository) }
   let(:source_sha) { create(:commit, project: project).id }
-  let(:target_sha) { create(:commit, project: project, git_commit: RepoHelpers.another_sample_commit).id }
+  let(:target_commit) { create(:commit, project: project, git_commit: RepoHelpers.another_sample_commit) }
+  let(:target_sha) { target_commit.id }
+  let(:target_short_sha) { target_commit.id.to_s[0..7] }
   let(:repository) { double(id: 1, fork: false) }
   let(:source_repo) { repository }
   let(:source_branch) { double(ref: 'branch-merged', repo: source_repo, sha: source_sha) }
   let(:forked_source_repo) { double(id: 2, fork: true, name: 'otherproject', full_name: 'company/otherproject') }
   let(:target_repo) { repository }
-  let(:target_branch) { double(ref: 'master', repo: target_repo, sha: target_sha) }
-  let(:removed_branch) { double(ref: 'removed-branch', repo: source_repo, sha: '2e5d3239642f9161dcbbc4b70a211a68e5e45e2b') }
-  let(:forked_branch) { double(ref: 'master', repo: forked_source_repo, sha: '2e5d3239642f9161dcbbc4b70a211a68e5e45e2b') }
+  let(:target_branch) { double(ref: 'master', repo: target_repo, sha: target_sha, user: octocat) }
+  let(:removed_branch) { double(ref: 'removed-branch', repo: source_repo, sha: '2e5d3239642f9161dcbbc4b70a211a68e5e45e2b', user: octocat) }
+  let(:forked_branch) { double(ref: 'master', repo: forked_source_repo, sha: '2e5d3239642f9161dcbbc4b70a211a68e5e45e2b', user: octocat) }
+  let(:branch_deleted_repo) { double(ref: 'master', repo: nil, sha: '2e5d3239642f9161dcbbc4b70a211a68e5e45e2b', user: octocat) }
   let(:octocat) { double(id: 123456, login: 'octocat', email: 'octocat@example.com') }
   let(:created_at) { DateTime.strptime('2011-01-26T19:01:12Z') }
   let(:updated_at) { DateTime.strptime('2011-01-27T19:01:12Z') }
@@ -203,16 +206,24 @@ describe Gitlab::GithubImport::PullRequestFormatter, lib: true do
     context 'when source branch does not exist' do
       let(:raw_data) { double(base_data.merge(head: removed_branch)) }
 
-      it 'prefixes branch name with pull request number' do
-        expect(pull_request.source_branch_name).to eq 'pull/1347/removed-branch'
+      it 'prefixes branch name with gh-:short_sha/:number/:user pattern to avoid collision' do
+        expect(pull_request.source_branch_name).to eq "gh-#{target_short_sha}/1347/octocat/removed-branch"
       end
     end
 
     context 'when source branch is from a fork' do
       let(:raw_data) { double(base_data.merge(head: forked_branch)) }
 
-      it 'prefixes branch name with pull request number and project with namespace to avoid collision' do
-        expect(pull_request.source_branch_name).to eq 'pull/1347/company/otherproject/master'
+      it 'prefixes branch name with gh-:short_sha/:number/:user pattern to avoid collision' do
+        expect(pull_request.source_branch_name).to eq "gh-#{target_short_sha}/1347/octocat/master"
+      end
+    end
+
+    context 'when source branch is from a deleted fork' do
+      let(:raw_data) { double(base_data.merge(head: branch_deleted_repo)) }
+
+      it 'prefixes branch name with gh-:short_sha/:number/:user pattern to avoid collision' do
+        expect(pull_request.source_branch_name).to eq "gh-#{target_short_sha}/1347/octocat/master"
       end
     end
   end
@@ -229,8 +240,8 @@ describe Gitlab::GithubImport::PullRequestFormatter, lib: true do
     context 'when target branch does not exist' do
       let(:raw_data) { double(base_data.merge(base: removed_branch)) }
 
-      it 'prefixes branch name with pull request number' do
-        expect(pull_request.target_branch_name).to eq 'pull/1347/removed-branch'
+      it 'prefixes branch name with gh-:short_sha/:number/:user pattern to avoid collision' do
+        expect(pull_request.target_branch_name).to eq 'gl-2e5d3239/1347/octocat/removed-branch'
       end
     end
   end
@@ -290,6 +301,14 @@ describe Gitlab::GithubImport::PullRequestFormatter, lib: true do
       end
     end
 
+    context 'when source repository does not exist anymore' do
+      let(:raw_data) { double(base_data.merge(head: branch_deleted_repo)) }
+
+      it 'returns true' do
+        expect(pull_request.cross_project?).to eq true
+      end
+    end
+
     context 'when source and target repositories are the same' do
       let(:raw_data) { double(base_data.merge(head: source_branch)) }
 
@@ -299,6 +318,14 @@ describe Gitlab::GithubImport::PullRequestFormatter, lib: true do
     end
   end
 
+  describe '#source_branch_exists?' do
+    let(:raw_data) { double(base_data.merge(head: forked_branch)) }
+
+    it 'returns false when is a cross_project' do
+      expect(pull_request.source_branch_exists?).to eq false
+    end
+  end
+
   describe '#url' do
     let(:raw_data) { double(base_data) }