Apply working-tree changes to the current branch and automatically restack every upstack descendant. User input: $ARGUMENTS.

Modes

• Amend (default) — folds staged changes into the existing commit. PR keeps the same identity; force-push needed on next submit.

  gt modify -a              # stage all + amend
  gt modify                 # amend already-staged changes

• New commit — adds a new commit on the same branch.

  gt modify -cam "fix tests"        # stage all + new commit with message
  gt modify -cm "fix tests"         # already-staged changes + new commit with message

  Always pass -m "<message>" — gt modify -c alone opens $EDITOR for the message, which hangs in a non-interactive shell.
• Into a downstack branch — amend changes into an ancestor branch, then restack upward.

  gt modify --into <ancestor-branch>

Steps

1. Run git status --short and gt ls so the user sees what is staged and where it will land.
2. Pick the mode from $ARGUMENTS. If ambiguous (multi-commit branch already exists), ask the user: amend or new commit? Amend keeps the branch single-commit (preferred Graphite style); new commit makes it a multi-commit branch that may need gt squash later.
3. Run the chosen gt modify command.
4. If the auto-restack hits conflicts:
   • Resolve in the editor.
   • gt add . to mark resolved.
   • gt continue -a to finish the restack chain.
   • gt abort to back out cleanly.
5. Run gt ls to confirm the new state.

Key flags

• -a, --all — stage all modified files before amending
• -c, --commit — create a new commit instead of amending
• -m, --message <msg> — commit message (for -c or to reword on amend)
• -p, --patch — interactive hunk staging
• --into <branch> — amend into a downstack branch in one step

When to use gt absorb instead

If the working-tree changes belong to multiple downstack branches (e.g. you fixed several bugs across the stack), use gt absorb -a — Graphite picks the right branch per hunk.