CODEWITHSUNDEEP
gitgit-rebasegit-filter-branchgit-rewrite-history
Tobi
Tobi

Reputation: 2749

Prepend string to messages of a range of git commits

I have a range of commits in my local git repository with the following messages: 

Added source.h
Broken link fixed
Corrected unit test
Deleted deprecated algorithm
...

Before pushing them to the server, I would like to prepend ticket information to every commit message:

Ticket #9999 (1): Added source.h
Ticket #9999 (2): Broken link fixed
Ticket #9999 (3): Corrected unit test
Ticket #9999 (4): Deleted deprecated algorithm
...

Of course I could git rebase and reword every sigle commit, but I would like to automate the process as it's so repetitive.

I think it should somehow be possible with git filter-branch, but the environment variables only provide GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, GIT_AUTHOR_DATE, GIT_COMMITTER_NAME, GIT_COMMITTER_EMAIL, and GIT_COMMITTER_DATE, but not the message.

How can I access and automatically manipulate the commit messages?

EDIT: Note that the ticket number is always the same, but the number in the brackets is incremented successively.

Upvotes: 1

Views: 823

Answers (3)

Tobi
Tobi

Reputation: 2749

Following the hint from Mark to use the --msg-filter option of filter-branch, the full solution is:

If the commit range is XXX..HEAD, the bracketed number can be expressed with git rev-list --count XXX..$GIT_COMIIT. Thus the messages can be transformed with sed:

git filter-branch --msg-filter '
    i=`git rev-list --count XXX..$GIT_COMIIT`
    sed "1s/^/Ticket #9999 ($i): /"
    ' XXX..HEAD

Upvotes: 2

Mark Adelsberger
Mark Adelsberger

Reputation: 45659

Assuming you have logic for which ticket number to attach to each message, you would use the --msg-filter option of filter-branch. See the docs at https://git-scm.com/docs/git-filter-branch for details.

Upvotes: 2

Harry10932
Harry10932

Reputation: 56

There is a githook for this exact functionality.

This code will prepend the branch name to the commit message:

#!/bin/sh

BRANCH_NAME=$(git branch 2>/dev/null | grep -e ^* | tr -d ' *')
if [ -n "$BRANCH_NAME" ]; then
    echo "[$BRANCH_NAME] $(cat $1)" > $1
fi

If you want to get this working you first need to make an executable in the .git/hooks directory in your repo and call it commit-msg.

See this link for the source above: https://gist.github.com/bartoszmajsak/1396344/97081e76ab275f5fe526347908503febd1340495

Also another useful link about git hooks: https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks

Upvotes: 2

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