Git

Forks

How to update a fork from the upstream branch

First add the upstream remote, let’s call it upstream. Then display it to make sure it took. Then fetch the code and rebase it into master. Finally push it up to the fork remote, probably origin.

$ git remote add upstream git@github.com:scrapinghub/varanus.git
$ git remote -v
$ git checkout master
$ git fetch upstream
$ git rebase upstream/master
$ git push

Ref Log

How to get back files from atomic actions

I’m saying “atomic actions” here to mean something that you told Git to do which is no longer in any of your branches we see in the normal log. The fact is that it might still available in the reflog.

Scenario: I made changes to two files which I committed in a single commit. I realized I wanted them to be in two separate commits so I reverted one of the file’s changes and merged it back into the commit. This as you may have guessed erased my changes to the second file.

To get the changes back from the second file I did:

$ git reflog

0442192 (HEAD -> stdhttp) HEAD@{1}: rebase (continue) (pick): TEMP: count index 0
c41e23b HEAD@{2}: rebase (continue) (fixup): f: server: gold signal
584d118 HEAD@{3}: rebase: fast-forward
ce8f2bf HEAD@{4}: rebase -i (start): checkout
eaf27f2 HEAD@{5}: rebase (continue) (finish): returning to refs/heads/stdhttp
eaf27f2 HEAD@{6}: rebase (continue) (pick): TEMP: count index 0
042ec6b HEAD@{7}: rebase (continue) (pick): f: tx revert
584d118 HEAD@{8}: rebase -i (start): checkout
d6664ce HEAD@{9}: commit: f: tx revert
669952e HEAD@{10}: commit: TEMP: count index 0
584d118 HEAD@{11}: commit: f: server: gold signal
ce8f2bf HEAD@{12}: commit: f: server: good job

I could see the line where I committed the reversion (I’m glad I take the extra half-second to give meaningful names to my fixups):

d6664ce HEAD@{9}: commit: f: tx revert

So then I did:

$ git co 669952e -- ./src/bot/telegram/telethonx.py

I got this from Joshua Wehner’s blog post: How to undo (almost) anything with Git in the section Redo after undo “local”.