Using Git

Use this skill when the task involves Git operations in the RISC OS build environment, especially when preparing commits or reasoning about a dirty worktree.

Core rules

• Prefer non-interactive Git commands.
• Never use git add ., git add <directory>, or other broad staging when a narrower file list is possible.
• Never revert or overwrite unrelated user changes unless the user explicitly asks for that.
• Do not use destructive commands such as git reset --hard or git checkout -- unless explicitly requested.
• Expect the worktree to contain many unrelated untracked files. Filter for the exact files relevant to the current task.
• If the .git in the repository is a file, which refers to a non-existant directory, we are in a snapshot of a git submodule. We cannot do git operations. Do not try - give up and tell the user.

Status and inspection

Start with targeted inspection:

git status --short
git diff -- path/to/file
git diff --cached -- path/to/file
git rev-parse --short HEAD

When only a few files matter, ask Git about those files directly rather than trying to interpret the whole repository state.

Be explicit about whether you want unstaged or staged changes:

• git diff -- path/to/file compares the working tree against the index, so it shows only unstaged changes.
• git diff --cached -- path/to/file compares the index against HEAD, so use it when changes have already been staged and plain git diff appears empty.

Staging

Stage only the intended files:

git add path/to/file1 path/to/file2

If the worktree is noisy, prefer:

git status --short -- path/to/file1 path/to/file2

before committing, to confirm that only the intended paths are staged or modified.

Commit messages

Use a short summary line followed by a wrapped body when needed.

Rules:

• Keep the subject concise and imperative.
• Wrap commit message body lines to 74 characters.
• Do not embed literal \n escape sequences in git commit -m bodies.
• If a multiline message is needed, feed it from standard input or a file.
• A good description opens with a short sentence or paragraph about why the change is being made so that the context is understood. This is important for code archeology - working out why something went wrong and what the reason was for a mistake.
• This can then be followed by the detail about what has been done to address this, and how it has been tested.
• It may include how the change is deficient because of time, or just because it's progressive work, etc
• If relevant, include information about how it was tested, but don't go into excessive detail.
• You may avoid these rules and make just a simple description if the change is self-explanatory - adding documentation, correcting typos, etc - or where background would not help. But never commit only a title line; there must always be some body text.

Preferred pattern:

printf '%s\n' \
  'Short subject line' \
  '' \
  'First wrapped body line.' \
  'Second wrapped body line.' | git commit -F -

Use multiple -m arguments only for separate paragraphs, not to simulate line wrapping with escaped newlines.

Dirty worktrees

This environment often has:

• unrelated modified files,
• many untracked files,
• generated output under .rotransform/, build/, or similar paths.

Guidance:

• Ignore unrelated untracked files unless they are directly relevant.
• Read carefully before committing if a file is already modified.
• If a file has unrelated user edits, integrate with them rather than replacing them.
• If the change set is mixed, commit only the files that belong to the current task.

Environment-specific notes

Lessons from this environment:

• The repository may contain wrapper tools on PATH with familiar names. Check which executable is being used if command behaviour looks unusual.
• If a shell one-liner needs a multiline commit message, prefer printf piped into git commit -F -.
• Commit messages should be wrapped properly because literal backslash escapes are not interpreted inside ordinary single-quoted shell strings.
• When testing or building inside the environment, generated files should remain uncommitted unless they are part of the requested source change.

When to use this skill

Use this skill for tasks such as:

• preparing a clean commit from a noisy worktree,
• writing or reviewing commit messages,
• staging only selected files,
• checking whether a repository is safe to commit,
• comparing local changes before a release or integration step.