git log --before=“4 months” show me branches that have commits from 3 weeks ago. what am I doing wrong?

问题

so I have this snippet that I want to use to filter out branches that doesn't have a certain prefix and that hasn't received any commits in over 3 months so that I can remove them from our remote later on.

 for k in $(git branch -r | awk -Forigin !'/\/Prefix1\/|\/prefix2\//'); do
  if [ "$(git log -1 --before="3 month" $k)" ]; then
    echo "$(git log -1 --pretty=format:"%ci, %cr, " $k) $k";
  fi;
done

The problem is currently that when I run this I see branches that have received commits 3 weeks ago, 5 months ago, 2 months ago, 1 month ago etc etc and I can't figure out why.

But if I only run: git log --before="4 month" --pretty=format:"%ci, %cr, " It works as intended.

Can anyone give me any guidance?

回答1:

The -1 in git log -1 [filters] $k will :

unroll the history of git log [filters] $k
limit this history to its first line

So if a branch has a 3 month old commit in its history (I would guess : any of your branches does), git log -1 --before="3 month" $k will always show 1 line -- the first commit in its history that is more than 3 month old.

Your leading if [ ... ] condition will always be true.

To fix that, you can limit the range of commits to select only the leading commit of each branch :