branchcache: do not accept "empty update"
This currently does not happens and it will be simpler that is remains that way.
If all update do something, we will be able to simply declare, in a later
changesets, that all update to result in a dirty branchcache.
Test temp file used with an editor has the expected suffix.
$ hg init repo
$ cd repo
Create an editor that writes its arguments to stdout and set it to $HGEDITOR.
$ cat > editor.sh << EOF
> echo "\$@"
> exit 1
> EOF
$ hg add editor.sh
$ HGEDITOR="sh $TESTTMP/repo/editor.sh"
$ export HGEDITOR
Verify that the path for a commit editor has the expected suffix.
$ hg commit
*.commit.hg.txt (glob)
abort: edit failed: sh exited with status 1
[250]
Verify that the path for a histedit editor has the expected suffix.
$ cat >> $HGRCPATH <<EOF
> [extensions]
> rebase=
> histedit=
> EOF
$ hg commit --message 'At least one commit for histedit.'
$ hg histedit
*.histedit.hg.txt (glob)
abort: edit failed: sh exited with status 1
[250]
Verify that when performing an action that has the side-effect of creating an
editor for a diff, the file ends in .diff.
$ echo 1 > one
$ echo 2 > two
$ hg add
adding one
adding two
$ hg commit --interactive --config ui.interactive=true --config ui.interface=text << EOF
> y
> e
> q
> EOF
diff --git a/one b/one
new file mode 100644
examine changes to 'one'?
(enter ? for help) [Ynesfdaq?] y
@@ -0,0 +1,1 @@
+1
record change 1/2 to 'one'?
(enter ? for help) [Ynesfdaq?] e
*.diff (glob)
editor exited with exit code 1
record change 1/2 to 'one'?
(enter ? for help) [Ynesfdaq?] q
abort: user quit
[250]