Find committed version of an external patched file

Question

I've found a patched file in a old forum thread of a file for which I've a git repository.

I'd like to find out what version of the file was used (probably the one with less diffstat?)

I'm still a git newbie.

Is there already some git builtin for a check like this? If not, how do I list each changed version of the file and checkout a particular version? (There's only the master branch)

Answer 1

If you open the patch file (assuming it was generated using git format-patch), you will find a line like:

diff --git a/file.py b/file.py
index a344535..477ede1 100644

Here, a344535, 477ede1 are both commit id's (they are the shortened SHA/commit ids).

To checkout the file version from which the patch was generated, do a checkout on the commit

git checkout a344535

And now, you can do a gitk (might need to install with apt-get) on the repository to check further history.

Note: the git checkout <SHA> above will take you to a detached head state, so don't forget to do a git checkout master once you want to start working on your repo again.