phabricator: use Phabricator's last node information
This makes it more strict when checking whether or not we should update a
Differential Revision. For example,
a) Alice updates D1 to content 1.
b) Bob updates D1 to content 2.
c) Alice tries to update D1 to content 1.
Previously, `c)` will do nothing because `phabsend` detects the patch is not
changed. A more correct behavior is to override Bob's update here, hence the
patch.
This also makes it possible to return a reaonsable "last node" when there is
no tags but only `Differential Revision` commit messages.
Test Plan:
```
for i in A B C; do echo $i > $i; hg ci -m $i -A $i; done
hg phabsend 0::
# D40: created
# D41: created
# D42: created
echo 3 >> C; hg amend; hg phabsend .
# D42: updated
hg tag --local --hidden -r 2 -f D42
# move tag to the previous version
hg phabsend .
# D42: skipped (previously it would be "updated")
rm -rf .hg; hg init
hg phabread --stack D42 | hg import -
hg phabsend .
# D42: updated
hg tag --local --remove D42
hg commit --amend
hg phabsend .
# D42: updated (no new diff uploaded, previously it will upload a new diff)
```
The old diff object is now returned, which could be useful in the next
patch.
Differential Revision: https://phab.mercurial-scm.org/D121
$ hg init
$ echo This is file a1 > a
$ echo This is file b1 > b
$ hg add a b
$ hg commit -m "commit #0"
$ echo This is file b22 > b
$ hg commit -m "comment #1"
$ hg update 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm b
$ hg commit -A -m "comment #2"
removing b
created new head
$ hg update 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm b
$ hg update -c 2
abort: uncommitted changes
[255]
$ hg revert b
$ hg update -c 2
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mv a c
Should abort:
$ hg update 1
abort: uncommitted changes
(commit or update --clean to discard changes)
[255]
$ mv c a
Should succeed:
$ hg update 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved