want per-file regexp for enclosing function in diff
Filed retrospectively from <https:/
Let me summarize:
1. It's not always easy to find the "current branch" to be able to get its config.
2. having "-F regex" specified only globally is not flexible enough, as different branches (e.g. one with the C code, another with the Python code) may need different regexps.
2.1 Actually, even one regexp per branch is not enough, as one branch may have both python and C files.
3. Allowing the user to specify arbitrary diff options that affect all generated diffs is too dangerous - "diff -w" will break merge bundles (and "diff -c" breaks bzr shelve and everything that parses diffs).
3.1 But "diff -p" seems to be safe everywhere.
So, I took another approach. It's more strict and more flexible at the same time. More flexible as in the 2.1 above (regexp can be specified per file or a group of files) and more strict as in the 3.1 above (only diff -p - really, diff -F - is allowed).