push: rework the computation of fallbackheads to be correct
The previous computation tried to be smart but ended up being wrong. This was
caught by phase movement test while reworking the phase discovery logic to be
faster.
The previous logic was failing to catch case where the pushed set was not based
on a common heads (i.e. when the discovery seemed to have "over discovered"
content, outside the pushed set)
In the following graph, `e` is a common head and we `hg push -r f`. We need to
detect `c` as a fallback heads and we previous failed to do so::
e
|
d f
|/
c
|
b
|
a
The performance impact of the change seems minimal. On the most impacted
repository at hand (mozilla-try), the slowdown seems mostly mixed in the
overall noise `hg push` but seems to be in the hundred of milliseconds order of
magnitude. When using rust, we seems to be a bit faster, probably because we
leverage more accelaratd internals.
I added a couple of performance related common for further investigation later
on.
$ heads()
> {
> hg heads --template '{rev}: {desc|firstline|strip} ({branches})\n' "$@"
> }
$ hg init a
$ cd a
$ echo 'root' >root
$ hg add root
$ hg commit -m "Adding root node"
$ heads
0: Adding root node ()
-------
$ heads .
0: Adding root node ()
=======
$ echo 'a' >a
$ hg add a
$ hg branch a
marked working directory as branch a
(branches are permanent and global, did you want a bookmark?)
$ hg commit -m "Adding a branch"
$ heads
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
1: Adding a branch (a)
=======
$ hg update -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo 'b' >b
$ hg add b
$ hg branch b
marked working directory as branch b
$ hg commit -m "Adding b branch"
$ heads
2: Adding b branch (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
2: Adding b branch (b)
=======
$ echo 'bh1' >bh1
$ hg add bh1
$ hg commit -m "Adding b branch head 1"
$ heads
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
3: Adding b branch head 1 (b)
=======
$ hg update -C 2
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo 'bh2' >bh2
$ hg add bh2
$ hg commit -m "Adding b branch head 2"
created new head
$ heads
4: Adding b branch head 2 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
$ heads .
4: Adding b branch head 2 (b)
3: Adding b branch head 1 (b)
=======
$ hg update -C 2
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo 'bh3' >bh3
$ hg add bh3
$ hg commit -m "Adding b branch head 3"
created new head
$ heads
5: Adding b branch head 3 (b)
4: Adding b branch head 2 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
5: Adding b branch head 3 (b)
4: Adding b branch head 2 (b)
3: Adding b branch head 1 (b)
=======
$ hg merge 4
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m "Merging b branch head 2 and b branch head 3"
$ heads
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
=======
$ echo 'c' >c
$ hg add c
$ hg branch c
marked working directory as branch c
$ hg commit -m "Adding c branch"
$ heads
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
7: Adding c branch (c)
=======
$ heads -r 3 .
no open branch heads found on branches c (started at 3)
[1]
$ heads -r 2 .
7: Adding c branch (c)
-------
$ hg update -C 4
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
-------
$ heads -r 3 .
3: Adding b branch head 1 (b)
-------
$ heads -r 2 .
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
$ heads -r 7 .
no open branch heads found on branches b (started at 7)
[1]
=======
$ for i in 0 1 2 3 4 5 6 7; do
> hg update -C "$i"
> heads
> echo '-------'
> heads .
> echo '-------'
> done
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
0: Adding root node ()
-------
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
1: Adding a branch (a)
-------
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
7: Adding c branch (c)
-------
=======
$ for i in a b c z; do
> heads "$i"
> echo '-------'
> done
1: Adding a branch (a)
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
7: Adding c branch (c)
-------
abort: unknown revision 'z'
-------
=======
$ heads 0 1 2 3 4 5 6 7
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
Topological heads:
$ heads -t
7: Adding c branch (c)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
$ cd ..
______________
"created new head" message tests
$ hg init newheadmsg
$ cd newheadmsg
Init: no msg
$ echo 1 > a
$ hg ci -Am "a0: Initial root"
adding a
$ echo 2 >> a
$ hg ci -m "a1 (HN)"
$ hg branch b
marked working directory as branch b
(branches are permanent and global, did you want a bookmark?)
$ echo 1 > b
$ hg ci -Am "b2: Initial root for branch b"
adding b
$ echo 2 >> b
$ hg ci -m "b3 (HN)"
Case NN: msg
$ hg up -q null
$ hg branch -f b
marked working directory as branch b
$ echo 1 > bb
$ hg ci -Am "b4 (NN): new topo root for branch b"
adding bb
created new head
Case HN: no msg
$ echo 2 >> bb
$ hg ci -m "b5 (HN)"
Case BN: msg
$ hg branch -f default
marked working directory as branch default
$ echo 1 > aa
$ hg ci -Am "a6 (BN): new branch root"
adding aa
created new head
Case CN: msg
$ hg up -q 4
$ echo 3 >> bbb
$ hg ci -Am "b7 (CN): regular new head"
adding bbb
created new head
Case BB: msg
$ hg up -q 4
$ hg merge -q 3
$ hg branch -f default
marked working directory as branch default
$ hg ci -m "a8 (BB): weird new branch root"
created new head
Case CB: msg
$ hg up -q 4
$ hg merge -q 1
$ hg ci -m "b9 (CB): new head from branch merge"
created new head
Case HB: no msg
$ hg up -q 7
$ hg merge -q 6
$ hg ci -m "b10 (HB): continuing head from branch merge"
Case CC: msg
$ hg up -q 4
$ hg merge -q 2
$ hg ci -m "b11 (CC): new head from merge"
created new head
Case CH: no msg
$ hg up -q 2
$ hg merge -q 10
$ hg ci -m "b12 (CH): continuing head from merge"
Case HH: no msg
$ hg merge -q 3
$ hg ci -m "b12 (HH): merging two heads"
$ cd ..