commitctx: document a fast path in _filecommit
This block cut off a lot of logic, documenting the why and how seems useful to
future reader.
This is part of a larger refactoring/cleanup of the commitctx code to clarify
and augment the logic gathering metadata useful for copy tracing. The current
code is a tad too long and entangled to make such update easy. We start with
easy and small cleanup.
Differential Revision: https://phab.mercurial-scm.org/D8700
--- a/mercurial/localrepo.py Tue Jul 21 13:36:48 2020 -0700
+++ b/mercurial/localrepo.py Mon Jul 06 19:13:19 2020 +0200
@@ -2802,6 +2802,9 @@
touched = 'added'
if isinstance(fctx, context.filectx):
+ # This block fast path most comparisons which are usually done. It
+ # assumes that bare filectx is used and no merge happened, hence no
+ # need to create a new file revision in this case.
node = fctx.filenode()
if node in [fparent1, fparent2]:
self.ui.debug(b'reusing %s filelog entry\n' % fname)