How to make commit-message/loop counter work correctly, with git filter-repo --commit-callback ?

[marfeljoergsen]

Hi,

I have previously used git filter-branch - but understand it's deprecated and I should instead use git-filter-repo. I usually have a bunch of commits and when I'm done I would like to prepend the first line of the commit-message with a ticket-number and I would often like to append a counter telling which commit this is out of how many commits in total there are. I made a small bash-script:

#!/usr/bin/env bash

if [[ $# -eq 0 || ( -z $PREPEND && -z $APPEND ) ]]; then
   echo "Use this script with environment variables: \"PREPEND=... and APPEND=... $0 RANGE\""
    exit 0
else
   RANGE="$1"
   echo "Arguments are:"
   [[ -z $PREPEND ]] || echo "   PREPEND=\"$PREPEND\""
   [[ -z $APPEND ]] || echo "   APPEND=\"$APPEND\""
   echo -e "   RANGE=\"$RANGE\"\n"
fi
set -e # exit when any command fails

ncom=$(git rev-list --count "$RANGE")

git filter-repo --commit-callback '
i = 1
msg = commit.message.decode("utf-8")
pp = "'"$PREPEND"'"
ap = "'"$APPEND"'"
newmsgList = msg.split('"'\n'"')
newmsgList[0] = pp + newmsgList[0] + ap.replace("?/?", str(i) + "/'$ncom'") # prepend & append first line of commit message
newmsg = '"'\n'"'.join(newmsgList)
commit.message = newmsg.encode("utf-8")
' --force --refs "$RANGE"

Save the above as e.g. /tmp/addComm and "chmod +x" on this file. It's used like this (first prepend the ticket number, next use the special "?/?" syntax, which should be replaced):

PREPEND="#1234: " APPEND=" (?/?)" /tmp/addComm "HEAD~4..HEAD"

It mostly works - except the commit-number counter:

f4360f499c (HEAD -> tmp) #1234: Revert "Implement ... whatever... feature" (1/4)
4682c4ebf4 #1234: Implement ... whatever... feature (1/4)
fdce69ca7c #1234: Revert "first commit..." (1/4)
1763c23c79 #1234: First commit out of four (1/4)

Only the first (1/4) is correct, the remaining is wrong. The correct result should be with increasing counter:

f4360f499c (HEAD -> tmp) #1234: Revert "Implement ... whatever... feature" (4/4)
4682c4ebf4 #1234: Implement ... whatever... feature (3/4)
fdce69ca7c #1234: Revert "first commit..." (2/4)
1763c23c79 #1234: First commit out of four (1/4)

My question is: How do I make the commit-counter work properly (with increasing commit-counter out of the total number of commits)? hmm... I guess a work-around is to make a loop inside the script and let "RANGE" be a single commit in the whole range of commits - so instead of calling "git filter-repo --commit-callback" on a range, I would have to call it for every commit in the loop... Maybe that's the only solution, to fix my counter-issue? hmm... Appreciate any feedback/ideas...