Draft: Send commit message as part of commit difftc-commit-msg-as-diff

The make it possible to comment on the commit message this change sends
the commit message as a diff file together with all the other changes in
the commit.

3 files changed, 68 insertions, 0 deletions

diff --git a/internal/gitaly/service/blob/get_blobs.go b/internal/gitaly/service/blob/get_blobs.go
index 2dcf4122f..9229f384f 100644
--- a/internal/gitaly/service/blob/get_blobs.go
+++ b/internal/gitaly/service/blob/get_blobs.go
@@ -32,6 +32,35 @@ func sendGetBlobsResponse(req *gitalypb.GetBlobsRequest, stream gitalypb.BlobSer
 			path = bytes.TrimRight(path, "/")
 		}
 
+		if bytes.Equal(path, []byte("COMMIT_MSG")) {
+			object, _ := c.Commit(ctx, git.Revision(revisionPath.Revision))
+
+			response := &gitalypb.GetBlobsResponse{
+				Revision: revision,
+				Oid:      revision,
+				Path:     path,
+				Size:     object.ObjectInfo.Size,
+				Mode:     0100644,
+			}
+
+			sw := streamio.NewWriter(func(p []byte) error {
+				msg := &gitalypb.GetBlobsResponse{}
+				if response != nil {
+					msg = response
+					response = nil
+				}
+
+				msg.Data = bytes.SplitN(p, []byte("\n\n"), 2)[1]
+				msg.Size = int64(len(msg.Data))
+
+				return stream.Send(msg)
+			})
+
+			io.Copy(sw, object.Reader)
+
+			continue
+		}
+
 		treeEntry, err := tef.FindByRevisionAndPath(ctx, revision, string(path))
 		if err != nil {
 			return err
diff --git a/internal/gitaly/service/diff/commit.go b/internal/gitaly/service/diff/commit.go
index 7f940ef90..bf127fb89 100644
--- a/internal/gitaly/service/diff/commit.go
+++ b/internal/gitaly/service/diff/commit.go
@@ -1,12 +1,14 @@
 package diff
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 
 	"github.com/grpc-ecosystem/go-grpc-middleware/logging/logrus/ctxlogrus"
 	log "github.com/sirupsen/logrus"
 	"gitlab.com/gitlab-org/gitaly/internal/git"
+	"gitlab.com/gitlab-org/gitaly/internal/git/localrepo"
 	"gitlab.com/gitlab-org/gitaly/internal/gitaly/diff"
 	"gitlab.com/gitlab-org/gitaly/proto/go/gitalypb"
 	"google.golang.org/grpc/codes"
@@ -72,6 +74,27 @@ func (s *server) CommitDiff(in *gitalypb.CommitDiffRequest, stream gitalypb.Diff
 	limits.SafeMaxLines = int(in.SafeMaxLines)
 	limits.SafeMaxBytes = int(in.SafeMaxBytes)
 
+	{
+		repo := localrepo.New(s.gitCmdFactory, in.GetRepository(), s.cfg)
+		commit, err := repo.ReadCommit(stream.Context(), git.Revision(rightSha))
+
+		if err == nil {
+			patch := fmt.Sprintf("@@ -0,0 +1,%d @@\n%s", bytes.Count(commit.Body, []byte("\n")), commit.Body)
+
+			response := &gitalypb.CommitDiffResponse{
+				FromPath:     []byte("COMMIT_MSG"),
+				ToPath:       []byte("COMMIT_MSG"),
+				FromId:       git.ZeroOID.String(),
+				ToId:         rightSha,
+				OldMode:      0,
+				NewMode:      0100644,
+				RawPatchData: []byte(patch),
+				EndOfPatch:   true,
+			}
+			stream.Send(response)
+		}
+	}
+
 	return s.eachDiff(stream.Context(), "CommitDiff", in.Repository, cmd, limits, func(diff *diff.Diff) error {
 		response := &gitalypb.CommitDiffResponse{
 			FromPath:       diff.FromPath,
diff --git a/internal/gitaly/service/diff/numstat.go b/internal/gitaly/service/diff/numstat.go
index 44c65bf9f..02ab319c0 100644
--- a/internal/gitaly/service/diff/numstat.go
+++ b/internal/gitaly/service/diff/numstat.go
@@ -1,9 +1,11 @@
 package diff
 
 import (
+	"bytes"
 	"io"
 
 	"gitlab.com/gitlab-org/gitaly/internal/git"
+	"gitlab.com/gitlab-org/gitaly/internal/git/localrepo"
 	"gitlab.com/gitlab-org/gitaly/internal/gitaly/diff"
 	"gitlab.com/gitlab-org/gitaly/proto/go/gitalypb"
 	"google.golang.org/grpc/codes"
@@ -35,6 +37,20 @@ func (s *server) DiffStats(in *gitalypb.DiffStatsRequest, stream gitalypb.DiffSe
 
 	parser := diff.NewDiffNumStatParser(cmd)
 
+	{
+		repo := localrepo.New(s.gitCmdFactory, in.GetRepository(), s.cfg)
+		commit, err := repo.ReadCommit(stream.Context(), git.Revision(in.RightCommitId))
+		if err == nil {
+			numStat := &gitalypb.DiffStats{
+				Additions: int32(bytes.Count(commit.Body, []byte("\n"))),
+				Deletions: 0,
+				Path:      []byte("COMMIT_MSG"),
+				OldPath:   []byte("COMMIT_MSG"),
+			}
+			batch = append(batch, numStat)
+		}
+	}
+
 	for {
 		stat, err := parser.NextNumStat()
 		if err != nil {