Using git to identify all modified functions in a revision

Question

Is there a good way to use git to identify all the modified functions in each revision in the history? I've tried using the -p switch, but it doesn't seem to work in the same way that svn's show-c-function parameter works.

My assumption is that I'll want to use "git diff HEAD~i HEAD~i-1 -p" for increasing values of i. Am I missing some parameters that will help identify diff's best guess on the functions that were modified?

Answer 1

Here is a magic chant to list functions within a git diff ^*

git diff |                  \
grep -E '^(@@)' |           \
grep "(" |                  \
sed 's/@@.*@@//' |          \
sed 's/(.*//' |             \
awk -F " " '{print $NF}' |  \
uniq

...and what it does is...

1. Picks the current diff,
2. next picks only lines with "hunk-headers" ,
3. next picks only lines with opening parenthesis (as potentially containing function names),
4. next ignores the hunk headers,
5. next ignores the text after the opening parenthesis,
6. next picks only the word immediately before the opening parenthesis,
7. and lastly ignores multiple occurrences of the same word in the list.

Voila! you have a list of functions being modified by the current git diff.

---

^{* Verified using git version 2.7.4 on Ubuntu 16.04 running bash.}

Answer 2

Here's a quick and dirty attempt at what I think you're going for. It does a git log to show all revisions, -p to include the diff in the log, a grep to only include the lines containing the commit ID and the hunk headers, and uses sed to filter out the line numbers, leaving only the guess at the function name that Git writes after the hunk header.

git log -p | grep -E '^(commit|@@)' | sed 's/@@.*@@//'