config: extract diff-related coreconfigitem()s to a helper method We already have 'annotate' and 'diff' that use the same set of options, and I want to add more in a followup commit, so I'm attempting to reduce maintenance burden and duplication by making it possible to register all of them at once. Differential Revision: https://phab.mercurial-scm.org/D5832

commit: ignore diff whitespace settings when doing `commit -i` (issue5839) Previously, we respected options like `diff.ignoreblanklines` and `diff.ignorews`. This can cause problems when the user is attempting to actually commit the blank line change. Specifically, the split extension can get into an infinite loop because it detects that the working copy is not clean, but when we get the diff we don't see the changes, so it just skips popping up the chunk selection flow, saying there's no changes to record. These options are primarily meant for viewing diffs; it is highly unlikely that someone is actually intending to add extraneous whitespace and have it ignored if they attempt to interactively commit (but *not* ignored if they non-interactively commit). Differential Revision: https://phab.mercurial-scm.org/D5744

tests: add syntax warnings on Python 3.8 in python-zstandard These are warnings from upstream test code. Let's just acknowledge them for now. These should go away in a future python-zstandard release :) Differential Revision: https://phab.mercurial-scm.org/D5846