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
#!/bin/sh
#
# Use this script to generate branches.svndump
#
mkdir temp
cd temp
mkdir project-orig
cd project-orig
mkdir trunk
mkdir branches
cd ..
svnadmin create svn-repo
svnurl=file://`pwd`/svn-repo
svn import project-orig $svnurl -m "init projA"
svn co $svnurl project
cd project
echo a > trunk/a
echo b > trunk/b
echo c > trunk/c
mkdir trunk/dir
echo e > trunk/dir/e
# Add a file within branches, used to confuse branch detection
echo d > branches/notinbranch
svn add trunk/a trunk/b trunk/c trunk/dir branches/notinbranch
svn ci -m hello
svn up
# Branch to old
svn copy trunk branches/old
svn rm branches/old/c
svn rm branches/old/dir
svn ci -m "branch trunk, remove c and dir"
svn up
# Update trunk
echo a >> trunk/a
svn ci -m "change a"
# Update old branch
echo b >> branches/old/b
svn ci -m "change b"
# Create a cross-branch revision
svn move trunk/b branches/old/c
echo c >> branches/old/c
svn ci -m "move and update c"
# Update old branch again
echo b >> branches/old/b
svn ci -m "change b again"
# Move back and forth between branch of similar names
# This used to generate fake copy records
svn up
svn move branches/old branches/old2
svn ci -m "move to old2"
svn move branches/old2 branches/old
svn ci -m "move back to old"
# Update trunk again
echo a > trunk/a
svn ci -m "last change to a"
# Branch again from a converted revision
svn copy -r 1 $svnurl/trunk branches/old3
svn ci -m "branch trunk@1 into old3"
cd ..
svnadmin dump svn-repo > ../branches.svndump