rust-changelog: don't skip empty lines when iterating over changeset lines
The first empty line in the changeset indicates the end of headers and
beginning of description. Callers can't know figure out where that
position is if empty lines are skipped.
Differential Revision: https://phab.mercurial-scm.org/D12426
Test update.requiredest
$ cd $TESTTMP
$ cat >> $HGRCPATH <<EOF
> [commands]
> update.requiredest = True
> EOF
$ hg init repo
$ cd repo
$ echo a >> a
$ hg commit -qAm aa
$ hg up
abort: you must specify a destination
(for example: hg update ".::")
[10]
$ hg up .
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ HGPLAIN=1 hg up
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg --config commands.update.requiredest=False up
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd ..
Check update.requiredest interaction with pull --update
$ hg clone repo clone
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd repo
$ echo a >> a
$ hg commit -qAm aa
$ cd ../clone
$ hg pull --update
abort: update destination required by configuration
(use hg pull followed by hg update DEST)
[10]
$ cd ..
update.requiredest should silent the "hg update" text after pull
$ hg init repo1
$ cd repo1
$ hg pull ../repo
pulling from ../repo
requesting all changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files
new changesets 8f0162e483d0:048c2cb95949