absorb: preserve changesets which were already empty
Most commands in Mercurial (commit, rebase, absorb itself) don’t create empty
changesets or drop them if they become empty. If there’s a changeset that’s
empty, it must be a deliberate choice of the user. At least it shouldn’t be
absorb’s responsibility to prune them. The fact that changesets that became
empty during absorb are pruned, is unaffected by this.
This case was found while writing patches which make it possible to configure
absorb and rebase to not drop empty changesets. Even without having such config
set, I think it’s valuable to preserve changesets which were already empty.
$ . $TESTDIR/wireprotohelpers.sh
$ hg init server
$ enablehttpv2 server
$ cd server
$ hg debugdrawdag << EOF
> C D
> |/
> B
> |
> A
> EOF
$ hg up B
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg branch branch1
marked working directory as branch branch1
(branches are permanent and global, did you want a bookmark?)
$ echo b1 > foo
$ hg -q commit -A -m 'branch 1'
$ hg up B
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg branch branch2
marked working directory as branch branch2
$ echo b2 > foo
$ hg -q commit -A -m 'branch 2'
$ hg log -T '{rev}:{node} {branch} {desc}\n'
5:224161c7589aa48fa83a48feff5e95b56ae327fc branch2 branch 2
4:b5faacdfd2633768cb3152336cc0953381266688 branch1 branch 1
3:be0ef73c17ade3fc89dc41701eb9fc3a91b58282 default D
2:26805aba1e600a82e93661149f2313866a221a7b default C
1:112478962961147124edd43549aedd1a335e44bf default B
0:426bada5c67598ca65036d57d9e4b64b0c1ce7a0 default A
$ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
$ cat hg.pid > $DAEMON_PIDS
No arguments returns something reasonable
$ sendhttpv2peer << EOF
> command branchmap
> EOF
creating http peer for wire protocol version 2
sending branchmap command
response: {
b'branch1': [
b'\xb5\xfa\xac\xdf\xd2c7h\xcb1R3l\xc0\x953\x81&f\x88'
],
b'branch2': [
b'"Aa\xc7X\x9a\xa4\x8f\xa8:H\xfe\xff^\x95\xb5j\xe3\'\xfc'
],
b'default': [
b'&\x80Z\xba\x1e`\n\x82\xe96a\x14\x9f#\x13\x86j"\x1a{',
b'\xbe\x0e\xf7<\x17\xad\xe3\xfc\x89\xdcAp\x1e\xb9\xfc:\x91\xb5\x82\x82'
]
}
$ cat error.log