view tests/test-mq-qqueue.t @ 42743:8c9a6adec67a

rust-discovery: using the children cache in add_missing

The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.

The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.

This is a case where staying on the same side of the interface
between the two languages has clear benefits.

On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.

For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:

Rust version with simple iteration
  addcommons: 57.287us
  first undecided computation: 184.278334ms
  first children cache computation: 131.056us
  addmissings iteration: 42.766us
  first addinfo total: 185.24 ms

Python + C version
  first addcommons: 0.29 ms
  addcommons 0.21 ms
  first undecided computation 191.35 ms
  addmissings 45.75 ms
  first addinfo total: 237.77 ms

On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:

Rust version:
  first undecided computation: 293.842629ms
  first children cache computation: 407.911297ms
  addmissings iteration: 34.312869ms
  first addinfo total: 776.02 ms
  taking initial sample
  query 2: sampling time: 1318.38 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings: 143.062us

Python + C version:
  first undecided computation 298.13 ms
  addmissings 80.13 ms
  first addinfo total: 399.62 ms
  taking initial sample
  query 2: sampling time: 3957.23 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings 52.88 ms

Differential Revision: https://phab.mercurial-scm.org/D6428

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init foo
  $ cd foo
  $ echo a > a
  $ hg ci -qAm a

Default queue:

  $ hg qqueue
  patches (active)

  $ echo b > a
  $ hg qnew -fgDU somestuff

Applied patches in default queue:

  $ hg qap
  somestuff

Try to change patch (create succeeds, switch fails):

  $ hg qqueue foo --create
  abort: new queue created, but cannot make active as patches are applied
  [255]

  $ hg qqueue
  foo
  patches (active)

Empty default queue:

  $ hg qpop
  popping somestuff
  patch queue now empty

Switch queue:

  $ hg qqueue foo
  $ hg qqueue
  foo (active)
  patches

List queues, quiet:

  $ hg qqueue --quiet
  foo
  patches

Fail creating queue with already existing name:

  $ hg qqueue --create foo
  abort: queue "foo" already exists
  [255]

  $ hg qqueue
  foo (active)
  patches

Create new queue for rename:

  $ hg qqueue --create bar

  $ hg qqueue
  bar (active)
  foo
  patches

Rename queue, same name:

  $ hg qqueue --rename bar
  abort: can't rename "bar" to its current name
  [255]

Rename queue to existing:

  $ hg qqueue --rename foo
  abort: queue "foo" already exists
  [255]

Rename queue:

  $ hg qqueue --rename buz

  $ hg qqueue
  buz (active)
  foo
  patches

Switch back to previous queue:

  $ hg qqueue foo
  $ hg qqueue --delete buz

  $ hg qqueue
  foo (active)
  patches

Create queue for purge:

  $ hg qqueue --create purge-me

  $ hg qqueue
  foo
  patches
  purge-me (active)

Create patch for purge:

  $ hg qnew patch-purge-me

  $ ls -1d .hg/patches-purge-me 2>/dev/null || true
  .hg/patches-purge-me

  $ hg qpop -a
  popping patch-purge-me
  patch queue now empty

Purge queue:

  $ hg qqueue foo
  $ hg qqueue --purge purge-me

  $ hg qqueue
  foo (active)
  patches

  $ ls -1d .hg/patches-purge-me 2>/dev/null || true

Unapplied patches:

  $ hg qun
  $ echo c > a
  $ hg qnew -fgDU otherstuff

Fail switching back:

  $ hg qqueue patches
  abort: new queue created, but cannot make active as patches are applied
  [255]

Fail deleting current:

  $ hg qqueue foo --delete
  abort: cannot delete currently active queue
  [255]

Switch back and delete foo:

  $ hg qpop -a
  popping otherstuff
  patch queue now empty

  $ hg qqueue patches
  $ hg qqueue foo --delete
  $ hg qqueue
  patches (active)

Tricky cases:

  $ hg qqueue store --create
  $ hg qnew journal

  $ hg qqueue
  patches
  store (active)

  $ hg qpop -a
  popping journal
  patch queue now empty

  $ hg qqueue patches
  $ hg qun
  somestuff

Invalid names:

  $ hg qqueue test/../../bar --create
  abort: invalid queue name, may not contain the characters ":\/."
  [255]

  $ hg qqueue . --create
  abort: invalid queue name, may not contain the characters ":\/."
  [255]

  $ cd ..