Use Git's patience diff algorithm for interactive add

Question

I'd like to use Git's patience diff algorithm (the one you get if you invoke git diff with the --patience argument) with git add -p. How can I do this?

Background: I'm working with some XML files, and git diff's normal algorithm produces pretty poor diffs due to "misaligned" entry/exit tags. If I run git diff --patience, I get much more useful diffs, but there's no obvious way to use these diffs in git add -p.

Answer 1

git add -p currently rejects diff flags, but you can use the diff.algorithm config option:

git config --global diff.algorithm patience

New in Git 1.8.2.

Answer 2

This worked for me:

git -c diff.algorithm=patience add -p [...]

I am running the latest git v2.1.0 in Cygwin.

Answer 3

Hmmmm... One thing you could do is pipe the output of git diff to a temporary place, then read it back in with git apply:

git diff --patience <commitA> <commitB> > /tmp/patch.out
# checkout a new branch or otherwise do what you need to prep
git apply < /tmp/patch.out

That'll apply the output of the diff to the working directory, but it won't commit or stage the changes. You can then run git add -p as you normally would, and the --patience diff will be the changes you're interactively adding.

There's no reason you couldn't pipe diff to apply directly, if it better suits your workflow. It's something I do fairly regularly when rebuilding my own local branches for production integration.

Looks like you can also use it as a merge strategy, so it might be the case that instead of interactively adding the diffs, you could simply create a branch with what you want, then merge it in.