Allow to resolve conflicts on UserMergeToRefid-go-allow-conflicts-on-merge

When AllowConflicts option is passed, let's set
the "ours" strategy to git-merge command

In this case we won't have the merge failed due to
the conflicts

5 files changed, 26 insertions, 35 deletions

diff --git a/changelogs/unreleased/id-go-allow-conflicts-on-merge.yml b/changelogs/unreleased/id-go-allow-conflicts-on-merge.yml
new file mode 100644
index 000000000..6bf95f668
--- /dev/null
+++ b/changelogs/unreleased/id-go-allow-conflicts-on-merge.yml
@@ -0,0 +1,5 @@
+---
+title: Allow to resolve conflicts on UserMergeToRef
+merge_request: 2642
+author:
+type: performance
diff --git a/cmd/gitaly-git2go/merge.go b/cmd/gitaly-git2go/merge.go
index 907e717c0..565d7921e 100644
--- a/cmd/gitaly-git2go/merge.go
+++ b/cmd/gitaly-git2go/merge.go
@@ -57,6 +57,10 @@ func (cmd *mergeSubcommand) Run(context.Context, io.Reader, io.Writer) error {
 	}
 	mergeOpts.RecursionLimit = git2go.MergeRecursionLimit
 
+	if request.AllowConflicts {
+		mergeOpts.FileFavor = git.MergeFileFavorOurs
+	}
+
 	index, err := repo.MergeCommits(ours, theirs, &mergeOpts)
 	if err != nil {
 		return fmt.Errorf("could not merge commits: %w", err)
diff --git a/internal/git2go/merge.go b/internal/git2go/merge.go
index 39b2efe15..3bc0337bb 100644
--- a/internal/git2go/merge.go
+++ b/internal/git2go/merge.go
@@ -37,6 +37,9 @@ type MergeCommand struct {
 	Ours string `json:"ours"`
 	// Theirs is the commit into which ours is to be merged.
 	Theirs string `json:"theirs"`
+	// AllowConflicts resolves conflicts that occurred on merge commit and
+	// overrides the conflicts with our changes.
+	AllowConflicts bool `json:"allow_conflicts"`
 }
 
 // MergeResult contains results from a merge.
diff --git a/internal/gitaly/service/operations/merge.go b/internal/gitaly/service/operations/merge.go
index 6dd16f82a..5e27e3ec8 100644
--- a/internal/gitaly/service/operations/merge.go
+++ b/internal/gitaly/service/operations/merge.go
@@ -318,12 +318,13 @@ func (s *Server) userMergeToRef(ctx context.Context, request *gitalypb.UserMerge
 
 	// Now, we create the merge commit...
 	merge, err := git2go.MergeCommand{
-		Repository: repoPath,
-		AuthorName: string(request.User.Name),
-		AuthorMail: string(request.User.Email),
-		Message:    string(request.Message),
-		Ours:       ref,
-		Theirs:     sourceRef,
+		Repository:     repoPath,
+		AuthorName:     string(request.User.Name),
+		AuthorMail:     string(request.User.Email),
+		Message:        string(request.Message),
+		Ours:           ref,
+		Theirs:         sourceRef,
+		AllowConflicts: request.AllowConflicts,
 	}.Run(ctx, s.cfg)
 	if err != nil {
 		if errors.Is(err, git2go.ErrInvalidArgument) {
@@ -350,23 +351,7 @@ func (s *Server) UserMergeToRef(ctx context.Context, in *gitalypb.UserMergeToRef
 		return nil, helper.ErrInvalidArgument(err)
 	}
 
-	// Ruby has grown a new feature since being ported to Go, and we don't
-	// handle that yet.
-	if !in.AllowConflicts {
-		return s.userMergeToRef(ctx, in)
-	}
-
-	client, err := s.ruby.OperationServiceClient(ctx)
-	if err != nil {
-		return nil, helper.ErrInternal(err)
-	}
-
-	clientCtx, err := rubyserver.SetHeaders(ctx, s.locator, in.GetRepository())
-	if err != nil {
-		return nil, err
-	}
-
-	return client.UserMergeToRef(clientCtx, in)
+	return s.userMergeToRef(ctx, in)
 }
 
 func isAncestor(ctx context.Context, repo repository.GitRepo, ancestor, descendant string) (bool, error) {
diff --git a/internal/gitaly/service/operations/merge_test.go b/internal/gitaly/service/operations/merge_test.go
index 37ad293a5..d1874b026 100644
--- a/internal/gitaly/service/operations/merge_test.go
+++ b/internal/gitaly/service/operations/merge_test.go
@@ -1,7 +1,6 @@
 package operations
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"io/ioutil"
@@ -718,25 +717,20 @@ func TestConflictsOnUserMergeToRefRequest(t *testing.T) {
 		FirstParentRef: []byte("refs/heads/" + mergeBranchName),
 	}
 
-	t.Run("allow conflicts to be merged with markers", func(t *testing.T) {
+	t.Run("resolves conflicts and overrides them with our changes", func(t *testing.T) {
 		request.AllowConflicts = true
 
 		resp, err := client.UserMergeToRef(ctx, request)
 		require.NoError(t, err)
 
-		var buf bytes.Buffer
-		cmd := exec.Command(config.Config.Git.BinPath, "-C", testRepoPath, "show", resp.CommitId)
-		cmd.Stdout = &buf
-		require.NoError(t, cmd.Run())
+		output := text.ChompBytes(testhelper.MustRunCommand(t, nil, "git", "-C", testRepoPath, "show", resp.CommitId))
 
-		bufStr := buf.String()
-		require.Contains(t, bufStr, "+<<<<<<< files/ruby/popen.rb")
-		require.Contains(t, bufStr, "+>>>>>>> files/ruby/popen.rb")
-		require.Contains(t, bufStr, "+<<<<<<< files/ruby/regex.rb")
-		require.Contains(t, bufStr, "+>>>>>>> files/ruby/regex.rb")
+		// Overrides conflicts with our changes
+		require.Contains(t, output, `/(zip|tar|7z|tar\.gz|tgz|gz|tar\.bz2|tbz|tbz2|tb2|bz2)/`)
+		require.Contains(t, output, "options = { chdir: path }")
 	})
 
-	t.Run("disallow conflicts to be merged", func(t *testing.T) {
+	t.Run("disallow to be merged due to the conflicts", func(t *testing.T) {
 		request.AllowConflicts = false
 
 		_, err := client.UserMergeToRef(ctx, request)