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
https://bz.mercurial-scm.org/1306
Initialize remote repo with branches:
$ hg init remote
$ cd remote
$ echo a > a
$ hg ci -Ama
adding a
$ hg branch br
marked working directory as branch br
(branches are permanent and global, did you want a bookmark?)
$ hg ci -Amb
$ echo c > c
$ hg ci -Amc
adding c
$ hg log
changeset: 2:ae3d9c30ec50
branch: br
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: c
changeset: 1:3f7f930ca414
branch: br
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: b
changeset: 0:cb9a9f314b8b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a
$ cd ..
Try cloning -r branch:
$ hg clone -rbr remote local1
adding changesets
adding manifests
adding file changes
added 3 changesets with 2 changes to 2 files
new changesets cb9a9f314b8b:ae3d9c30ec50
updating to branch br
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg -R local1 parents
changeset: 2:ae3d9c30ec50
branch: br
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: c
Try cloning -rother clone#branch:
$ hg clone -r0 remote#br local2
adding changesets
adding manifests
adding file changes
added 3 changesets with 2 changes to 2 files
new changesets cb9a9f314b8b:ae3d9c30ec50
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg -R local2 parents
changeset: 0:cb9a9f314b8b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a
Try cloning -r1 clone#branch:
$ hg clone -r1 remote#br local3
adding changesets
adding manifests
adding file changes
added 3 changesets with 2 changes to 2 files
new changesets cb9a9f314b8b:ae3d9c30ec50
updating to branch br
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg -R local3 parents
changeset: 1:3f7f930ca414
branch: br
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: b