Implement auto-resolution of JSONL merge conflicts during bd sync

- Add isInRebase() to detect rebase state
- Add hasJSONLConflict() to check for JSONL-only conflicts
- Add runGitRebaseContinue() to continue rebase after resolution
- Auto-export from DB and resolve conflict when detected
- Add comprehensive tests for auto-resolution logic

Implements bd-cwmt

cmd/bd/sync_test.go

@@ -441,3 +441,169 @@ func TestGetSyncBranch_EnvOverridesDB(t *testing.T) {
 		t.Errorf("getSyncBranch() = %q, want %q (env override)", branch, "env-branch")
 	}
 }
+
+func TestIsInRebase_NotInRebase(t *testing.T) {
+	tmpDir := t.TempDir()
+	originalWd, _ := os.Getwd()
+	defer os.Chdir(originalWd)
+
+	// Create a git repo
+	os.Chdir(tmpDir)
+	exec.Command("git", "init").Run()
+	exec.Command("git", "config", "user.email", "test@test.com").Run()
+	exec.Command("git", "config", "user.name", "Test User").Run()
+
+	// Create initial commit
+	os.WriteFile("test.txt", []byte("test"), 0644)
+	exec.Command("git", "add", "test.txt").Run()
+	exec.Command("git", "commit", "-m", "initial").Run()
+
+	// Should not be in rebase
+	if isInRebase() {
+		t.Error("expected false when not in rebase")
+	}
+}
+
+func TestIsInRebase_InRebase(t *testing.T) {
+	tmpDir := t.TempDir()
+	originalWd, _ := os.Getwd()
+	defer os.Chdir(originalWd)
+
+	// Create a git repo
+	os.Chdir(tmpDir)
+	exec.Command("git", "init").Run()
+	exec.Command("git", "config", "user.email", "test@test.com").Run()
+	exec.Command("git", "config", "user.name", "Test User").Run()
+
+	// Create initial commit
+	os.WriteFile("test.txt", []byte("test"), 0644)
+	exec.Command("git", "add", "test.txt").Run()
+	exec.Command("git", "commit", "-m", "initial").Run()
+
+	// Simulate rebase by creating rebase-merge directory
+	os.MkdirAll(filepath.Join(tmpDir, ".git", "rebase-merge"), 0755)
+
+	// Should detect rebase
+	if !isInRebase() {
+		t.Error("expected true when .git/rebase-merge exists")
+	}
+}
+
+func TestIsInRebase_InRebaseApply(t *testing.T) {
+	tmpDir := t.TempDir()
+	originalWd, _ := os.Getwd()
+	defer os.Chdir(originalWd)
+
+	// Create a git repo
+	os.Chdir(tmpDir)
+	exec.Command("git", "init").Run()
+
+	// Simulate non-interactive rebase by creating rebase-apply directory
+	os.MkdirAll(filepath.Join(tmpDir, ".git", "rebase-apply"), 0755)
+
+	// Should detect rebase
+	if !isInRebase() {
+		t.Error("expected true when .git/rebase-apply exists")
+	}
+}
+
+func TestHasJSONLConflict_NoConflict(t *testing.T) {
+	tmpDir := t.TempDir()
+	originalWd, _ := os.Getwd()
+	defer os.Chdir(originalWd)
+
+	// Create a git repo
+	os.Chdir(tmpDir)
+	exec.Command("git", "init").Run()
+	exec.Command("git", "config", "user.email", "test@test.com").Run()
+	exec.Command("git", "config", "user.name", "Test User").Run()
+
+	// Create initial commit
+	os.WriteFile("test.txt", []byte("test"), 0644)
+	exec.Command("git", "add", "test.txt").Run()
+	exec.Command("git", "commit", "-m", "initial").Run()
+
+	// Should not have JSONL conflict
+	if hasJSONLConflict() {
+		t.Error("expected false when no conflicts")
+	}
+}
+
+func TestHasJSONLConflict_OnlyJSONLConflict(t *testing.T) {
+	tmpDir := t.TempDir()
+	originalWd, _ := os.Getwd()
+	defer os.Chdir(originalWd)
+
+	// Create a git repo
+	os.Chdir(tmpDir)
+	exec.Command("git", "init", "-b", "main").Run()
+	exec.Command("git", "config", "user.email", "test@test.com").Run()
+	exec.Command("git", "config", "user.name", "Test User").Run()
+
+	// Create initial commit
+	beadsDir := filepath.Join(tmpDir, ".beads")
+	os.MkdirAll(beadsDir, 0755)
+	os.WriteFile(filepath.Join(beadsDir, "beads.jsonl"), []byte(`{"id":"bd-1","title":"original"}`), 0644)
+	exec.Command("git", "add", ".").Run()
+	exec.Command("git", "commit", "-m", "initial").Run()
+
+	// Create a second commit on main (modify same issue)
+	os.WriteFile(filepath.Join(beadsDir, "beads.jsonl"), []byte(`{"id":"bd-1","title":"main-version"}`), 0644)
+	exec.Command("git", "add", ".").Run()
+	exec.Command("git", "commit", "-m", "main change").Run()
+
+	// Create a branch from the first commit
+	exec.Command("git", "checkout", "-b", "feature", "HEAD~1").Run()
+	os.WriteFile(filepath.Join(beadsDir, "beads.jsonl"), []byte(`{"id":"bd-1","title":"feature-version"}`), 0644)
+	exec.Command("git", "add", ".").Run()
+	exec.Command("git", "commit", "-m", "feature change").Run()
+
+	// Attempt rebase onto main (will conflict)
+	exec.Command("git", "rebase", "main").Run()
+
+	// Should detect JSONL conflict during rebase
+	if !hasJSONLConflict() {
+		t.Error("expected true when only beads.jsonl has conflict during rebase")
+	}
+}
+
+func TestHasJSONLConflict_MultipleConflicts(t *testing.T) {
+	tmpDir := t.TempDir()
+	originalWd, _ := os.Getwd()
+	defer os.Chdir(originalWd)
+
+	// Create a git repo
+	os.Chdir(tmpDir)
+	exec.Command("git", "init", "-b", "main").Run()
+	exec.Command("git", "config", "user.email", "test@test.com").Run()
+	exec.Command("git", "config", "user.name", "Test User").Run()
+
+	// Create initial commit with beads.jsonl and another file
+	beadsDir := filepath.Join(tmpDir, ".beads")
+	os.MkdirAll(beadsDir, 0755)
+	os.WriteFile(filepath.Join(beadsDir, "beads.jsonl"), []byte(`{"id":"bd-1","title":"original"}`), 0644)
+	os.WriteFile("other.txt", []byte("line1\nline2\nline3"), 0644)
+	exec.Command("git", "add", ".").Run()
+	exec.Command("git", "commit", "-m", "initial").Run()
+
+	// Create a second commit on main (modify both files)
+	os.WriteFile(filepath.Join(beadsDir, "beads.jsonl"), []byte(`{"id":"bd-1","title":"main-version"}`), 0644)
+	os.WriteFile("other.txt", []byte("line1\nmain-version\nline3"), 0644)
+	exec.Command("git", "add", ".").Run()
+	exec.Command("git", "commit", "-m", "main change").Run()
+
+	// Create a branch from the first commit
+	exec.Command("git", "checkout", "-b", "feature", "HEAD~1").Run()
+	os.WriteFile(filepath.Join(beadsDir, "beads.jsonl"), []byte(`{"id":"bd-1","title":"feature-version"}`), 0644)
+	os.WriteFile("other.txt", []byte("line1\nfeature-version\nline3"), 0644)
+	exec.Command("git", "add", ".").Run()
+	exec.Command("git", "commit", "-m", "feature change").Run()
+
+	// Attempt rebase (will conflict on both files)
+	exec.Command("git", "rebase", "main").Run()
+
+	// Should NOT auto-resolve when multiple files conflict
+	if hasJSONLConflict() {
+		t.Error("expected false when multiple files have conflicts (should not auto-resolve)")
+	}
+}