Git undo all changes with clearing reflog?

Question

How to undo all working changes in local repository for two month(new branches, commit, etc.)? Reflog history also need to clear.

Answer 1

This question will help you find the commit you want: How do I view all commits for a specific day? With your example, the first commit listed by this command is the one you want:

git log --until="2018-09-01"

Then you can use @phd's suggestion and reset your sandbox to that commit's sha1:

git reset --hard <sha1>

Warning: this reset command will also move the HEAD of your current branch to that commit. This is probably what you want but you need to be aware of it.

Unfortunately, you will have to do this for each branch one at a time, so I realize this is not the global solution you're looking for.

As for the reflog, I've looked at what expire does, and it cleans older references. I don't see how to remove the newest lines in the reflog, since that's contrary to what the reflog is intended to do. However, the reflog is stored in .git/logs/HEAD. Manually deleting lines from that file works, but I don't see an easy way to find which of those lines are after a specific date. If you edit this file, keep in mind the most recent entries are at the end, not at the beginning like git reflog shows.

Answer 2

1. Reset commit or index or worktree

   Choose one from the below:

   git reset --hard <commit>       # reset commit, index and worktree
   git reset [--mix] <commit>      # reset commit and index
   git reset --soft <commit>       # reset commit only
   

2. Remove the reflogs

   Choose one from the below:

   # removes all references of unreachable commits in reflog.
   git reflog expire --expire-unreachable=now --all
   
   # expire time: 2.month.ago or 2011-05-17.09:00:00
   git reflog expire --expire=<time> --expire-unreachable=now --all
   
   # clear reflog
   git reflog expire --expire=all --all
   

3. Cleanup unnecessary files and optimize the local repository

   git gc --prune=now