Record file copy operation with Git
When I move a file in git using git-mv the status shows that the file has been renamed and even if I alter some portions it still considers to be almost the same thing (which is good because it lets me follow the history of it).
When I copy a file the original file has some history I'd like to associate with the new copy.
I have tried moving the file then trying to re-checkout in the original location - once moved git won't let me checkout the original location.
I have tried doing a filesystem copy and then adding the file - git lists it as a new file.
Is there any way to make git record a file copy operation in a similar way to how it records a file rename/move where the history can be traced back to the original file?
Answer
Git does not do rename tracking nor copy tracking, which means it doesn't record renames or copies. What it does instead is rename and copy detection. You can request rename detection in git diff (and git show) by using the -M option, you can request additional copy detection in changed files by using the -C option (-C implies -M), and you can request more expensive copy detection among all files with --find-copies-harder or -C -C (which implies -C, which implies -M). See the git-diff manpage.
You can also configure git to always do rename detection by setting diff.renames to a boolean true value (e.g. true or 1), and you can request git to do copy detection too by setting it to copy or copies. See the git-config manpage.
Check also the -l option to git diff and the related config variable diff.renameLimit.
Note that git log <pathspec> works differently in Git: here <pathspec> is set of path delimiters, where path can be a (sub)directory name. It filters and simplifies history before rename and copy detection comes into play. If you want to follow renames and copies, use git log --follow <filename> (which currently is a bit limited, and works only for single file).