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.
$ cat >> $HGRCPATH << EOF
> [extensions]
> show =
> EOF
$ hg init repo0
$ cd repo0
Empty repo / no checkout results in error
$ hg show stack
abort: stack view only available when there is a working directory
[255]
Stack displays single draft changeset as root revision
$ echo 0 > foo
$ hg -q commit -A -m 'commit 0'
$ hg show stack
@ 9f17 commit 0
Stack displays multiple draft changesets
$ echo 1 > foo
$ hg commit -m 'commit 1'
$ echo 2 > foo
$ hg commit -m 'commit 2'
$ echo 3 > foo
$ hg commit -m 'commit 3'
$ echo 4 > foo
$ hg commit -m 'commit 4'
$ hg show stack
@ 2737 commit 4
o d1a6 commit 3
o 128c commit 2
o 181c commit 1
o 9f17 commit 0
Public parent of draft base is displayed, separated from stack
$ hg phase --public -r 0
$ hg show stack
@ 2737 commit 4
o d1a6 commit 3
o 128c commit 2
o 181c commit 1
/ (stack base)
o 9f17 commit 0
$ hg phase --public -r 1
$ hg show stack
@ 2737 commit 4
o d1a6 commit 3
o 128c commit 2
/ (stack base)
o 181c commit 1
Draft descendants are shown
$ hg -q up 2
$ hg show stack
o 2737 commit 4
o d1a6 commit 3
@ 128c commit 2
/ (stack base)
o 181c commit 1
$ hg -q up 3
$ hg show stack
o 2737 commit 4
@ d1a6 commit 3
o 128c commit 2
/ (stack base)
o 181c commit 1
working dir on public changeset should display special message
$ hg -q up 1
$ hg show stack
(empty stack; working directory parent is a published changeset)
Branch point in descendants displayed at top of graph
$ hg -q up 3
$ echo b > foo
$ hg commit -m 'commit 5 (new dag branch)'
created new head
$ hg -q up 2
$ hg show stack
\ / (multiple children)
|
o d1a6 commit 3
@ 128c commit 2
/ (stack base)
o 181c commit 1
$ cd ..
Base is stopped at merges
$ hg init merge-base
$ cd merge-base
$ echo 0 > foo
$ hg -q commit -A -m initial
$ echo h1 > foo
$ hg commit -m 'head 1'
$ hg -q up 0
$ echo h2 > foo
$ hg -q commit -m 'head 2'
$ hg phase --public -r 0:tip
$ hg -q up 1
$ hg merge -t :local 2
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m 'merge heads'
TODO doesn't yet handle case where wdir is a draft merge
$ hg show stack
@ 8ee9 merge heads
/ (stack base)
o 5947 head 1
$ echo d1 > foo
$ hg commit -m 'draft 1'
$ echo d2 > foo
$ hg commit -m 'draft 2'
$ hg show stack
@ 430d draft 2
o 787b draft 1
/ (stack base)
o 8ee9 merge heads
$ cd ..
Now move on to stacks when there are more commits after the base branchpoint
$ hg init public-rebase
$ cd public-rebase
$ echo 0 > foo
$ hg -q commit -A -m 'base'
$ hg phase --public -r .
$ echo d1 > foo
$ hg commit -m 'draft 1'
$ echo d2 > foo
$ hg commit -m 'draft 2'
$ hg -q up 0
$ echo 1 > foo
$ hg commit -m 'new 1'
created new head
$ echo 2 > foo
$ hg commit -m 'new 2'
$ hg -q up 2
Newer draft heads don't impact output
$ hg show stack
@ eaff draft 2
o 2b21 draft 1
/ (stack base)
o b66b base
Newer public heads are rendered
$ hg phase --public -r '::tip'
$ hg show stack
o baa4 new 2
/ (2 commits ahead)
:
: (stack head)
: @ eaff draft 2
: o 2b21 draft 1
:/ (stack base)
o b66b base
If rebase is available, we show a hint how to rebase to that head
$ hg --config extensions.rebase= show stack
o baa4 new 2
/ (2 commits ahead; hg rebase --source 2b21 --dest baa4)
:
: (stack head)
: @ eaff draft 2
: o 2b21 draft 1
:/ (stack base)
o b66b base
Similar tests but for multiple heads
$ hg -q up 0
$ echo h2 > foo
$ hg -q commit -m 'new head 2'
$ hg phase --public -r .
$ hg -q up 2
$ hg show stack
o baa4 new 2
/ (2 commits ahead)
: o 9a84 new head 2
:/ (1 commits ahead)
:
: (stack head)
: @ eaff draft 2
: o 2b21 draft 1
:/ (stack base)
o b66b base
$ hg --config extensions.rebase= show stack
o baa4 new 2
/ (2 commits ahead; hg rebase --source 2b21 --dest baa4)
: o 9a84 new head 2
:/ (1 commits ahead; hg rebase --source 2b21 --dest 9a84)
:
: (stack head)
: @ eaff draft 2
: o 2b21 draft 1
:/ (stack base)
o b66b base