Introduce diff3 based conflict resolver

cmd/squash_cherry_pick.go

@@ -28,6 +28,7 @@ var (
 		committerEmail  string
 		committerTime   string
 		ref             string
+		conflictRef     string
 		currentRefHash  string
 		abortOnConflict bool
 
@@ -53,6 +54,11 @@ var squashCherryPick = &cobra.Command{
 		}
 
 		client := &http.Client{Transport: &authnRoundtripper{}}
+		var conflictRef *plumbing.ReferenceName
+		if squashCherryPickArgs.conflictRef != "" {
+			r := plumbing.ReferenceName(squashCherryPickArgs.conflictRef)
+			conflictRef = &r
+		}
 		result, fetchDebugInfo, pushDebugInfo, pushErr := nichegit.PushSquashCherryPick(
 			squashCherryPickArgs.repoURL,
 			client,
@@ -63,6 +69,7 @@ var squashCherryPick = &cobra.Command{
 			author,
 			committer,
 			plumbing.ReferenceName(squashCherryPickArgs.ref),
+			conflictRef,
 			currentRefhash,
 			squashCherryPickArgs.abortOnConflict,
 		)
@@ -75,6 +82,8 @@ var squashCherryPick = &cobra.Command{
 			output.CherryPickedFiles = result.CherryPickedFiles
 			output.ConflictOpenFiles = result.ConflictOpenFiles
 			output.ConflictResolvedFiles = result.ConflictResolvedFiles
+			output.BinaryConflictFiles = result.BinaryConflictFiles
+			output.NonFileConflictFiles = result.NonFileConflictFiles
 		}
 		if output.CherryPickedFiles == nil {
 			output.CherryPickedFiles = []string{}
@@ -85,6 +94,12 @@ var squashCherryPick = &cobra.Command{
 		if output.ConflictResolvedFiles == nil {
 			output.ConflictResolvedFiles = []string{}
 		}
+		if output.BinaryConflictFiles == nil {
+			output.BinaryConflictFiles = []string{}
+		}
+		if output.NonFileConflictFiles == nil {
+			output.NonFileConflictFiles = []string{}
+		}
 		if pushErr != nil {
 			output.Error = pushErr.Error()
 		}
@@ -118,6 +133,8 @@ type squashCherryPickOutput struct {
 	CherryPickedFiles     []string             `json:"cherryPickedFiles"`
 	ConflictOpenFiles     []string             `json:"conflictOpenFiles"`
 	ConflictResolvedFiles []string             `json:"conflictResolvedFiles"`
+	BinaryConflictFiles   []string             `json:"binaryConflictFiles"`
+	NonFileConflictFiles  []string             `json:"nonFileConflictFiles"`
 	FetchDebugInfo        debug.FetchDebugInfo `json:"fetchDebugInfo"`
 	PushDebugInfo         *debug.PushDebugInfo `json:"pushDebugInfo"`
 	Error                 string               `json:"error,omitempty"`
@@ -137,6 +154,7 @@ func init() {
 	squashCherryPick.Flags().StringVar(&squashCherryPickArgs.committerEmail, "committer-email", "", "Commiter email address")
 	squashCherryPick.Flags().StringVar(&squashCherryPickArgs.committerTime, "committer-time", "", "Commit time in RFC3339 format (e.g. 2024-01-01T00:00:00Z)")
 	squashCherryPick.Flags().StringVar(&squashCherryPickArgs.ref, "ref", "", "A ref name (e.g. refs/heads/foobar) to push")
+	squashCherryPick.Flags().StringVar(&squashCherryPickArgs.conflictRef, "conflict-ref", "", "A ref name (e.g. refs/heads/foobar) to push when there's a conflict")
 	squashCherryPick.Flags().StringVar(&squashCherryPickArgs.currentRefHash, "current-ref-hash", "", "The expected current commit hash of the ref. If this is specified, the push will use the current commit hash. This is used for compare-and-swap.")
 	squashCherryPick.Flags().BoolVar(&squashCherryPickArgs.abortOnConflict, "abort-on-conflict", false, "Abort the operation if there is a merge conflict")
 	_ = squashCherryPick.MarkFlagRequired("repo-url")

e2e_tests/.gitignore

@@ -0,0 +1 @@
+/niche-git

e2e_tests/helper_git.go

@@ -0,0 +1,95 @@
+package e2e_tests
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/go-git/go-git/v5/plumbing"
+	"github.com/kr/text"
+	"github.com/stretchr/testify/require"
+)
+
+func NewTempRepo(t *testing.T) *GitTestRepo {
+	dir := t.TempDir()
+	init := exec.Command("git", "init", "--initial-branch=main")
+	init.Dir = dir
+	err := init.Run()
+	require.NoError(t, err, "failed to initialize git repository")
+	repo := &GitTestRepo{dir}
+	require.NoError(t, err, "failed to open repo")
+
+	settings := map[string]string{
+		"user.name":  "niche-git-test",
+		"user.email": "niche-git-test@nonexistant",
+	}
+	for k, v := range settings {
+		repo.Git(t, "config", k, v)
+	}
+
+	repo.CommitFile(t, "README.md", "Hello World")
+	return repo
+}
+
+type GitTestRepo struct {
+	RepoDir string
+}
+
+func (r *GitTestRepo) Git(t *testing.T, args ...string) string {
+	cmd := exec.Command("git", args...)
+	stdout := &bytes.Buffer{}
+	stderr := &bytes.Buffer{}
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+	cmd.Dir = r.RepoDir
+	err := cmd.Run()
+	var exitError *exec.ExitError
+	if err != nil && !errors.As(err, &exitError) {
+		t.Fatal(err)
+	}
+	t.Logf("Running git\n"+
+		"args: %v\n"+
+		"exit code: %v\n"+
+		"stdout:\n"+
+		"%s"+
+		"stderr:\n"+
+		"%s",
+		args,
+		cmd.ProcessState.ExitCode(),
+		text.Indent(stdout.String(), "  "),
+		text.Indent(stderr.String(), "  "),
+	)
+	return stdout.String()
+}
+
+func (r *GitTestRepo) AddFile(t *testing.T, fp string) {
+	r.Git(t, "add", fp)
+}
+
+func (r *GitTestRepo) CreateFile(t *testing.T, filename string, body string) string {
+	fp := filepath.Join(r.RepoDir, filename)
+	err := os.WriteFile(fp, []byte(body), 0644)
+	require.NoError(t, err, "failed to write file: %s", filename)
+	return fp
+}
+
+func (r *GitTestRepo) CommitFile(t *testing.T, filename string, body string) plumbing.Hash {
+	filepath := r.CreateFile(t, filename, body)
+	r.AddFile(t, filepath)
+
+	args := []string{"commit", "-m", fmt.Sprintf("Write %s", filename)}
+	r.Git(t, args...)
+	return plumbing.NewHash(strings.TrimSpace(r.Git(t, "rev-parse", "HEAD")))
+}
+
+func (r *GitTestRepo) ReadFile(t *testing.T, filename string) string {
+	fp := filepath.Join(r.RepoDir, filename)
+	bs, err := os.ReadFile(fp)
+	require.NoError(t, err, "failed to read file: %s", filename)
+	return string(bs)
+}

e2e_tests/helper_niche_git.go

@@ -0,0 +1,80 @@
+package e2e_tests
+
+import (
+	"bytes"
+	"errors"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+
+	"github.com/kr/text"
+	"github.com/stretchr/testify/require"
+)
+
+var nicheGitCmdPath string
+
+func init() {
+	cmd := exec.Command("go", "build", "../cmd/niche-git")
+	cmd.Stdout = os.Stderr
+	cmd.Stderr = os.Stderr
+
+	if err := cmd.Run(); err != nil {
+		panic(err)
+	}
+	var err error
+	nicheGitCmdPath, err = filepath.Abs("./niche-git")
+	if err != nil {
+		panic(err)
+	}
+}
+
+type NicheGitOutput struct {
+	ExitCode int
+	Stdout   string
+	Stderr   string
+}
+
+func cmd(t *testing.T, exe string, args ...string) NicheGitOutput {
+	cmd := exec.Command(exe, args...)
+	stdout := &bytes.Buffer{}
+	stderr := &bytes.Buffer{}
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+
+	err := cmd.Run()
+	var exitError *exec.ExitError
+	if err != nil && !errors.As(err, &exitError) {
+		t.Fatal(err)
+	}
+
+	output := NicheGitOutput{
+		ExitCode: cmd.ProcessState.ExitCode(),
+		Stdout:   stdout.String(),
+		Stderr:   stderr.String(),
+	}
+	t.Logf("Running niche-git\n"+
+		"args: %v\n"+
+		"exit code: %v\n"+
+		"stdout:\n"+
+		"%s"+
+		"stderr:\n"+
+		"%s",
+		args,
+		cmd.ProcessState.ExitCode(),
+		text.Indent(stdout.String(), "  "),
+		text.Indent(stderr.String(), "  "),
+	)
+	return output
+}
+
+func NicheGit(t *testing.T, args ...string) NicheGitOutput {
+	return cmd(t, nicheGitCmdPath, args...)
+}
+
+func RequireNicheGit(t *testing.T, args ...string) NicheGitOutput {
+	t.Helper()
+	output := NicheGit(t, args...)
+	require.Equal(t, 0, output.ExitCode, "niche-git %s: exited with %v", args, output.ExitCode)
+	return output
+}

e2e_tests/squash_cherry_pick_test.go

@@ -0,0 +1,124 @@
+package e2e_tests
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestSquashCherryPick_Conflict_Resolve(t *testing.T) {
+	repo := NewTempRepo(t)
+
+	baseHash := repo.CommitFile(t, "file1", `
+line 1
+line 2
+line 3
+line 4
+line 6
+line 7
+line 8
+line 9
+`)
+
+	repo.Git(t, "checkout", "-b", "feature")
+	featureHash := repo.CommitFile(t, "file1", `
+line 1
+line 2
+line 3
+line 4
+line 6
+line 7
+line 8
+line 9
+line 10
+`)
+	repo.Git(t, "checkout", "main")
+	targetHash := repo.CommitFile(t, "file1", `
+line 1
+line 2
+line 3
+line 4
+line 5
+line 6
+line 7
+line 8
+line 9
+`)
+
+	// At this point, featureHash adds line 10, targetHash adds line 5.
+	RequireNicheGit(t,
+		"squash-cherry-pick",
+		"--repo-url", "file://"+repo.RepoDir,
+		"--cherry-pick-from", featureHash.String(),
+		"--cherry-pick-to", targetHash.String(),
+		"--cherry-pick-base", baseHash.String(),
+		"--commit-message", "pick feature",
+		"--author", "cherry-picker",
+		"--author-email", "cherry-picker@nonexistent",
+		"--committer", "cherry-picker",
+		"--committer-email", "cherry-picker@nonexistent",
+		"--ref", "refs/heads/cherry-pick-result",
+	)
+	repo.Git(t, "checkout", "cherry-pick-result")
+	require.Equal(t, `
+line 1
+line 2
+line 3
+line 4
+line 5
+line 6
+line 7
+line 8
+line 9
+line 10
+`, repo.ReadFile(t, "file1"))
+}
+
+func TestSquashCherryPick_Conflict_Unresolved(t *testing.T) {
+	repo := NewTempRepo(t)
+
+	baseHash := repo.CommitFile(t, "file1", `
+line 1
+line 2
+line 3
+`)
+
+	repo.Git(t, "checkout", "-b", "feature")
+	featureHash := repo.CommitFile(t, "file1", `
+line 1
+line 5
+line 6
+`)
+	repo.Git(t, "checkout", "main")
+	targetHash := repo.CommitFile(t, "file1", `
+line 1
+line 8
+line 9
+`)
+
+	RequireNicheGit(t,
+		"squash-cherry-pick",
+		"--repo-url", "file://"+repo.RepoDir,
+		"--cherry-pick-from", featureHash.String(),
+		"--cherry-pick-to", targetHash.String(),
+		"--cherry-pick-base", baseHash.String(),
+		"--commit-message", "pick feature",
+		"--author", "cherry-picker",
+		"--author-email", "cherry-picker@nonexistent",
+		"--committer", "cherry-picker",
+		"--committer-email", "cherry-picker@nonexistent",
+		"--ref", "refs/heads/cherry-pick-result",
+		"--conflict-ref", "refs/heads/cherry-pick-conflict",
+	)
+	repo.Git(t, "checkout", "cherry-pick-conflict")
+	require.Equal(t, `
+line 1
+<<<<<<<<< Cherry-pick content
+line 5
+line 6
+=========
+line 8
+line 9
+>>>>>>>>> Base content
+`, repo.ReadFile(t, "file1"))
+}