CODEWITHSUNDEEP
gitdiff
Kevin Burke
Kevin Burke

Reputation: 65034

Generate a diff for a change that moved a function between files, and also changed slightly?

In a single commit, I moved a function to a new file, and also made some changes to it.

Github's diff viewer just shows ~30 lines deleted from the old file, and 30 lines added to the new file - it's hard to see what differences existed in the implementation of the old file and the new one.

Are there any tools that can help break down this diff? I can copy the relevant sections of each to a new file, and run diff on these, and generate a patch file I suppose...

Upvotes: 3

Views: 283

Answers (1)

frasertweedale
frasertweedale

Reputation: 5684

The command line git diff program has a heuristic for detecting renames but it is not turned on by default. Enable it via the -M[<n>] or --find-renames[=<n>] option. For example:

git show --find-renames <commit-sha>

As you have experienced, Git does not track renames. The heuristic it employs is to compare files that were deleted and added for similarity. The default similarity index is 50%, but this can be controlled with the =<n> argument. To increase the threshold to 90% (the files must be 90% the same to be considered a rename):

git show --find-renames=90% <commit-sha>

If you want git to always detect renames, there's a config knob for that:

git config --global diff.renames=true

For more information see the git-diff documentation.

Upvotes: 2

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