Merge branch 'eb/code-225' of _OKE5H2PQKOUfzFFDuD4FA/default/CODE/gitness (#70)

gitrpc/internal/gitea/merge.go

@@ -18,6 +18,7 @@ import (
 	"github.com/harness/gitness/gitrpc/enum"
 	"github.com/harness/gitness/gitrpc/internal/tempdir"
 	"github.com/harness/gitness/gitrpc/internal/types"
+	"github.com/rs/zerolog/log"
 
 	"code.gitea.io/gitea/modules/git"
 )
@@ -175,7 +176,7 @@ func (g Adapter) CreateTemporaryRepoForPR(
 func runMergeCommand(
 	ctx context.Context,
 	pr *types.PullRequest,
-	mergeMethod string,
+	mergeMethod enum.MergeMethod,
 	cmd *git.Command,
 	tmpBasePath string,
 	env []string,
@@ -254,6 +255,7 @@ func (g Adapter) Merge(
 	ctx context.Context,
 	pr *types.PullRequest,
 	mergeMethod enum.MergeMethod,
+	baseBranch string,
 	trackingBranch string,
 	tmpBasePath string,
 	mergeMsg string,
@@ -268,13 +270,14 @@ func (g Adapter) Merge(
 		mergeMsg = "Merge commit"
 	}
 
+	stagingBranch := "staging"
 	// TODO: sign merge commit
 	signArg := "--no-gpg-sign"
 
 	switch mergeMethod {
 	case enum.MergeMethodMerge:
 		cmd := git.NewCommand(ctx, "merge", "--no-ff", "--no-commit", trackingBranch)
-		if err := runMergeCommand(ctx, pr, string(mergeMethod), cmd, tmpBasePath, env); err != nil {
+		if err := runMergeCommand(ctx, pr, mergeMethod, cmd, tmpBasePath, env); err != nil {
 			return fmt.Errorf("unable to merge tracking into base: %w", err)
 		}
 
@@ -284,7 +287,7 @@ func (g Adapter) Merge(
 	case enum.MergeMethodSquash:
 		// Merge with squash
 		cmd := git.NewCommand(ctx, "merge", "--squash", trackingBranch)
-		if err := runMergeCommand(ctx, pr, string(mergeMethod), cmd, tmpBasePath, env); err != nil {
+		if err := runMergeCommand(ctx, pr, mergeMethod, cmd, tmpBasePath, env); err != nil {
 			return fmt.Errorf("unable to merge --squash tracking into base: %v", err)
 		}
 
@@ -311,6 +314,79 @@ func (g Adapter) Merge(
 					pr.HeadBranch, pr.BaseBranch, outbuf.String(), errbuf.String())
 			}
 		}
+	case enum.MergeMethodRebase:
+		// Checkout head branch
+		if err := git.NewCommand(ctx, "checkout", "-b", stagingBranch, trackingBranch).
+			Run(&git.RunOpts{
+				Dir:    tmpBasePath,
+				Stdout: &outbuf,
+				Stderr: &errbuf,
+			}); err != nil {
+			return fmt.Errorf("git checkout base prior to merge post staging rebase  [%s -> %s]: %v\n%s\n%s", pr.HeadBranch, pr.BaseBranch, err, outbuf.String(), errbuf.String())
+		}
+		outbuf.Reset()
+		errbuf.Reset()
+
+		// Rebase before merging
+		if err := git.NewCommand(ctx, "rebase", baseBranch).
+			Run(&git.RunOpts{
+				Dir:    tmpBasePath,
+				Stdout: &outbuf,
+				Stderr: &errbuf,
+			}); err != nil {
+			// Rebase will leave a REBASE_HEAD file in .git if there is a conflict
+			if _, statErr := os.Stat(filepath.Join(tmpBasePath, ".git", "REBASE_HEAD")); statErr == nil {
+				var commitSha string
+				// TBD git version we will support
+				// failingCommitPath := filepath.Join(tmpBasePath, ".git", "rebase-apply", "original-commit") // Git < 2.26
+				// if _, statErr := os.Stat(failingCommitPath); statErr != nil {
+				// 	return fmt.Errorf("git rebase staging on to base [%s -> %s]: %v\n%s\n%s", pr.HeadBranch, pr.BaseBranch, err, outbuf.String(), errbuf.String())
+				// }
+
+				failingCommitPath := filepath.Join(tmpBasePath, ".git", "rebase-merge", "stopped-sha") // Git >= 2.26
+				if _, statErr := os.Stat(failingCommitPath); statErr != nil {
+					return fmt.Errorf("git rebase staging on to base [%s -> %s]: %v\n%s\n%s", pr.HeadBranch, pr.BaseBranch, err, outbuf.String(), errbuf.String())
+				}
+
+				commitShaBytes, readErr := os.ReadFile(failingCommitPath)
+				if readErr != nil {
+					// Abandon this attempt to handle the error
+					return fmt.Errorf("git rebase staging on to base [%s -> %s]: %v\n%s\n%s", pr.HeadBranch, pr.BaseBranch, err, outbuf.String(), errbuf.String())
+				}
+				commitSha = strings.TrimSpace(string(commitShaBytes))
+
+				log.Debug().Msgf("RebaseConflict at %s [%s -> %s]: %v\n%s\n%s", commitSha, pr.HeadBranch, pr.BaseBranch, err, outbuf.String(), errbuf.String())
+				return &types.MergeConflictsError{
+					Method:    mergeMethod,
+					CommitSHA: commitSha,
+					StdOut:    outbuf.String(),
+					StdErr:    errbuf.String(),
+					Err:       err,
+				}
+			}
+			return fmt.Errorf("git rebase staging on to base [%s -> %s]: %v\n%s\n%s", pr.HeadBranch, pr.BaseBranch, err, outbuf.String(), errbuf.String())
+		}
+		outbuf.Reset()
+		errbuf.Reset()
+
+		// Checkout base branch again
+		if err := git.NewCommand(ctx, "checkout", baseBranch).
+			Run(&git.RunOpts{
+				Dir:    tmpBasePath,
+				Stdout: &outbuf,
+				Stderr: &errbuf,
+			}); err != nil {
+			return fmt.Errorf("git checkout base prior to merge post staging rebase  [%s -> %s]: %v\n%s\n%s", pr.HeadBranch, pr.BaseBranch, err, outbuf.String(), errbuf.String())
+		}
+		outbuf.Reset()
+		errbuf.Reset()
+
+		cmd := git.NewCommand(ctx, "merge", "--ff-only", stagingBranch)
+
+		// Prepare merge with commit
+		if err := runMergeCommand(ctx, pr, mergeMethod, cmd, tmpBasePath, env); err != nil {
+			return err
+		}
 	default:
 		return fmt.Errorf("wrong merge method provided: %s", mergeMethod)
 	}

gitrpc/internal/service/interface.go

@@ -46,7 +46,7 @@ type GitAdapter interface {
 	GetRefPath(refName string, refType enum.RefType) (string, error)
 	UpdateRef(ctx context.Context, repoPath, refName string, refType enum.RefType, newValue, oldValue string) error
 	CreateTemporaryRepoForPR(ctx context.Context, reposTempPath string, pr *types.PullRequest) (string, error)
-	Merge(ctx context.Context, pr *types.PullRequest, mergeMethod enum.MergeMethod, trackingBranch string,
+	Merge(ctx context.Context, pr *types.PullRequest, mergeMethod enum.MergeMethod, baseBranch, trackingBranch string,
 		tmpBasePath string, mergeMsg string, env []string, identity *types.Identity) error
 	GetMergeBase(ctx context.Context, repoPath, remote, base, head string) (string, string, error)
 	GetDiffTree(ctx context.Context, repoPath, baseBranch, headBranch string) (string, error)

gitrpc/internal/service/merge.go

@@ -169,10 +169,19 @@ func (s MergeService) Merge(
 		mergeMsg += "\n\n" + strings.TrimSpace(request.Message)
 	}
 
-	if err = s.adapter.Merge(ctx, pr, enum.MergeMethodFromRPC(request.Method), trackingBranch, tmpBasePath, mergeMsg, env, &types.Identity{
+	if err = s.adapter.Merge(
-		Name:  author.Name,
+		ctx,
-		Email: author.Email,
+		pr,
-	}); err != nil {
+		enum.MergeMethodFromRPC(request.Method),
+		baseBranch,
+		trackingBranch,
+		tmpBasePath,
+		mergeMsg,
+		env,
+		&types.Identity{
+			Name:  author.Name,
+			Email: author.Email,
+		}); err != nil {
 		return nil, processGitErrorf(err, "merge failed")
 	}
 

gitrpc/internal/types/errors.go

@@ -7,6 +7,8 @@ package types
 import (
 	"errors"
 	"fmt"
+
+	"github.com/harness/gitness/gitrpc/enum"
 )
 
 var (
@@ -29,10 +31,11 @@ var (
 
 // MergeConflictsError represents an error if merging fails with a conflict.
 type MergeConflictsError struct {
-	Method string
+	Method    enum.MergeMethod
-	StdOut string
+	CommitSHA string
-	StdErr string
+	StdOut    string
-	Err    error
+	StdErr    string
+	Err       error
 }
 
 func IsMergeConflictsError(err error) bool {
@@ -55,7 +58,7 @@ func (e *MergeConflictsError) Is(target error) bool {
 
 // MergeUnrelatedHistoriesError represents an error if merging fails due to unrelated histories.
 type MergeUnrelatedHistoriesError struct {
-	Method string
+	Method enum.MergeMethod
 	StdOut string
 	StdErr string
 	Err    error

web/src/pages/PullRequest/Conversation/PullRequestActionsBox/PullRequestActionsBox.tsx

@@ -88,7 +88,7 @@ export const PullRequestActionsBox: React.FC<PullRequestActionsBoxProps> = ({
       method: 'rebase',
       title: getString('pr.mergeOptions.rebaseAndMerge'),
       desc: getString('pr.mergeOptions.rebaseAndMergeDesc'),
-      disabled: true
+      disabled: false
     },
     {
       method: 'close',