Keep git history when splitting a file

git history git-svn
Paul Tarjan picture Paul Tarjan · Oct 8, 2010 · Viewed 10.8k times · Source

I want to take a function out of one file and put it into another, but keep the blame history.

cp a.php b.php

vim b.php
# delete everything but 1 function

vim a.php
# delete the 1 function

git add a.php b.php
git commit

But if I run git blame b.php I only see it blaming to this new commit.

Answer

vine77 picture vine77 · Nov 30, 2015

The general rule to maintaining blame history is to make a separate move commit first before any edits. It has been my experience that this allows git blame to work without the need for the -C option. So in the case of splitting the file up into new files, this can be done in two commits:

  1. Duplicate the original to the new destinations, making sure to delete the original
  2. Remove the extra sections from the duplicated files

In the example provided, this would be:

cp a.php b.php
mv a.php c.php
git add a.php b.php c.php
git commit
vim b.php  # delete everything but 1 function
vim c.php  # delete the 1 function
git add b.php c.php
git commit

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