histedit: don't crash if commit message is empty
If the commit message is empty, histedit will crash before this patch
because it assumes that `summary.splitlines()` is non-empty. One of
our users at work ran into this crash for a commit that was created by
an internal system.
I don't think we have a good way of testing this because it's hard to
create a commit with an empty commit message. I've added a comment to
help prevent regressions.
Differential Revision: https://phab.mercurial-scm.org/D9325
--- a/hgext/histedit.py Mon Nov 02 11:03:56 2020 +0100
+++ b/hgext/histedit.py Mon Nov 16 10:56:54 2020 -0800
@@ -533,7 +533,8 @@
summary = cmdutil.rendertemplate(
ctx, ui.config(b'histedit', b'summary-template')
)
- summary = summary.splitlines()[0]
+ # Handle the fact that `''.splitlines() => []`
+ summary = summary.splitlines()[0] if summary else b''
line = b'%s %s %s' % (self.verb, ctx, summary)
# trim to 75 columns by default so it's not stupidly wide in my editor
# (the 5 more are left for verb)