fix: scope gitm commit to the files the user selected

internal/cli/commit.go

@@ -214,7 +214,7 @@ func runCommitWithBranchLookup(ui ui, noPush bool, repoAliases []string, current
 		color.Green("  ✓ Staged %d file(s)", len(selectedFiles))
 
 		// 3e. Commit.
-		out, err := git.Commit(repo.Path, message)
+		out, err := git.Commit(repo.Path, message, selectedFiles)
 		if err != nil {
 			color.Red("  ✗ git commit failed: %v", err)
 			results = append(results, repoCommitResult{alias: repo.Alias, err: err})

internal/git/git.go

@@ -393,22 +393,14 @@ func UntrackedFiles(path string) ([]string, error) {
 // UntrackFiles removes files from the git index but keeps them on disk.
 // Equivalent to: git rm --cached -- <files>
 func UntrackFiles(path string, files []string) error {
-	cleaned := make([]string, 0, len(files))
-	for _, f := range files {
-		if len(f) > 3 {
-			cleaned = append(cleaned, strings.TrimSpace(f[3:]))
-		} else {
-			cleaned = append(cleaned, strings.TrimSpace(f))
-		}
-	}
-	args := append([]string{"rm", "--cached", "--"}, cleaned...)
+	args := append([]string{"rm", "--cached", "--"}, cleanPorcelainPaths(files)...)
 	_, err := run(path, args...)
 	return err
 }
 
-// StageFiles stages specific files (by their path relative to the repo root).
-func StageFiles(path string, files []string) error {
-	// Strip the porcelain status prefix (e.g. " M ", "?? ") to get the raw path.
+// cleanPorcelainPaths strips the two-char porcelain status prefix (e.g. " M ",
+// "?? ") from each line, yielding the bare repo-relative path.
+func cleanPorcelainPaths(files []string) []string {
 	cleaned := make([]string, 0, len(files))
 	for _, f := range files {
 		// porcelain format: "XY filename" where XY is two chars + space.
@@ -418,14 +410,23 @@ func StageFiles(path string, files []string) error {
 			cleaned = append(cleaned, strings.TrimSpace(f))
 		}
 	}
-	args := append([]string{"add", "--"}, cleaned...)
+	return cleaned
+}
+
+// StageFiles stages specific files (by their path relative to the repo root).
+func StageFiles(path string, files []string) error {
+	args := append([]string{"add", "--"}, cleanPorcelainPaths(files)...)
 	_, err := run(path, args...)
 	return err
 }
 
-// Commit creates a commit with the given message.
-func Commit(path, message string) (string, error) {
-	return run(path, "commit", "-m", message)
+// Commit creates a commit containing only the given files. Scoping the commit to
+// an explicit pathspec stops files that were already staged but NOT selected by the
+// user from leaking into the commit. Callers must pass a non-empty file list; an
+// empty list would degrade to a whole-index commit.
+func Commit(path, message string, files []string) (string, error) {
+	args := append([]string{"commit", "-m", message, "--"}, cleanPorcelainPaths(files)...)
+	return run(path, args...)
 }
 
 // Push pushes the current branch to origin.

internal/git/git_more_test.go

@@ -287,7 +287,7 @@ func TestPullAndPush(t *testing.T) {
 
 	writeFile(t, repo1, "local.txt", "local\n")
 	mustRunGit(t, repo1, "add", "local.txt")
-	if _, err := git.Commit(repo1, "local commit"); err != nil {
+	if _, err := git.Commit(repo1, "local commit", []string{"A  local.txt"}); err != nil {
 		t.Fatalf("Commit: %v", err)
 	}
 	if err := git.Push(repo1); err != nil {
@@ -355,6 +355,49 @@ func TestStageFilesAndDiscard(t *testing.T) {
 	}
 }
 
+// TestCommitOnlySelectedFiles guards against the regression where Commit ran a
+// bare `git commit`, sweeping the whole index — so a file that was already staged
+// but NOT selected by the user leaked into the commit. Commit must include only the
+// files passed to it and leave other staged files untouched.
+func TestCommitOnlySelectedFiles(t *testing.T) {
+	repo := initRepo(t)
+	makeCommit(t, repo, "selected.txt", "v1\n", "add selected")
+
+	// An unselected new file the user never chose, but already staged in the index.
+	writeFile(t, repo, "leak.txt", "leak\n")
+	mustRunGit(t, repo, "add", "leak.txt")
+
+	// The file the user actually selects (a tracked, unstaged modification).
+	writeFile(t, repo, "selected.txt", "v2\n")
+
+	selection := []string{" M selected.txt"}
+	if err := git.StageFiles(repo, selection); err != nil {
+		t.Fatalf("StageFiles: %v", err)
+	}
+	if _, err := git.Commit(repo, "commit selected only", selection); err != nil {
+		t.Fatalf("Commit: %v", err)
+	}
+
+	committed := mustRunGit(t, repo, "diff-tree", "--no-commit-id", "--name-only", "-r", "HEAD")
+	if !strings.Contains(committed, "selected.txt") {
+		t.Errorf("expected selected.txt in commit, got: %q", committed)
+	}
+	if strings.Contains(committed, "leak.txt") {
+		t.Errorf("leak.txt was committed but the user never selected it; committed files: %q", committed)
+	}
+
+	staged := stagedFiles(t, repo)
+	foundLeak := false
+	for _, f := range staged {
+		if f == "leak.txt" {
+			foundLeak = true
+		}
+	}
+	if !foundLeak {
+		t.Errorf("expected leak.txt to remain staged (not committed), staged files: %v", staged)
+	}
+}
+
 func TestIsDefaultBranch(t *testing.T) {
 	repo := initRepo(t)
 	branch, err := git.CurrentBranch(repo)