使用父提交的文本开始 git commit 的文本

Question

When you create a new commit in git, you can specify that you want your commit message editor to start up with the contents of a file, by specifying git commit -t <filename> or the commit.template environment variable. Is there a way to specify that you always want to use the full text of the parent commit as your template?

Context: My usual codebase, like many others, requires an annotation of what bug/issue a commit is work on to be present in every commit. Remembering bug/issue numbers is hard, and frequently I have a stack of commits on the same topic, to be submitted in sequence. It's awkward to use incantations like git commit; Ctrl+Z; g log -1; <click>; Shift+Ctrl+C; fg; Shift+Ctrl+V git commit; Ctrl+Z; g log -1; <click>; Shift+Ctrl+C; fg; Shift+Ctrl+V git commit; Ctrl+Z; g log -1; <click>; Shift+Ctrl+C; fg; Shift+Ctrl+V , which is what I'm usually forced to do.

Answer 1

You should just need to run:

git commit -C HEAD --reset-author -e

or more generally:

git commit -C $TEMPLATE_COMMIT_SHA1 --reset-author -e

The relevant online documentation items are:

• https://git-scm.com/docs/git-commit#Documentation/git-commit.txt--Cltcommitgt

  -C
  --reuse-message=<commit>

  Take an existing commit object, and reuse the log message and the authorship information (including the timestamp) when creating the commit.

• https://git-scm.com/docs/git-commit#Documentation/git-commit.txt--e

  -e
  --edit

  The message taken from file with -F , command line with -m , and from commit object with -C are usually used as the commit log message unmodified. This option lets you further edit the message taken from these sources.

• and as suggested by @KevinReid:

  https://git-scm.com/docs/git-commit#Documentation/git-commit.txt---reset-author

  --reset-author

  When used with -C/-c/--amend options, or when committing after a conflicting cherry-pick, declare that the authorship of the resulting commit now belongs to the committer. This also renews the author timestamp.

If you want to make this command more practical, eg by relying on an env. variable TEMPLATE_COMMIT_SHA1 , you can define a git alias such as:

# "committ" stands for "commit-template"
git config alias.committ '!f(){ set -x; git commit -C "${TEMPLATE_COMMIT_SHA1:-HEAD}" --reset-author -e "$@"; }; f'

# or if you prefer to make this alias available for all repos:
git config --global alias.committ '!f(){ set -x; git commit -C "${TEMPLATE_COMMIT_SHA1:-HEAD}" --reset-author -e "$@"; }; f'

# demo
touch a; git add a; git committ

export TEMPLATE_COMMIT_SHA1=HEAD^^^
touch b; git add b; git committ