view tests/test-basic.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

Create a repository:

#if no-extraextensions
  $ hg config
  devel.all-warnings=true
  devel.default-date=0 0
  extensions.fsmonitor= (fsmonitor !)
  largefiles.usercache=$TESTTMP/.cache/largefiles
  lfs.usercache=$TESTTMP/.cache/lfs
  ui.slash=True
  ui.interactive=False
  ui.merge=internal:merge
  ui.mergemarkers=detailed
  ui.promptecho=True
  web.address=localhost
  web\.ipv6=(?:True|False) (re)
  web.server-header=testing stub value
#endif

  $ hg init t
  $ cd t

Prepare a changeset:

  $ echo a > a
  $ hg add a

  $ hg status
  A a

Writes to stdio succeed and fail appropriately

#if devfull
  $ hg status 2>/dev/full
  A a

  $ hg status >/dev/full
  abort: No space left on device
  [255]
#endif

#if devfull
  $ hg status >/dev/full 2>&1
  [255]

  $ hg status ENOENT 2>/dev/full
  [255]
#endif

  $ hg commit -m test

This command is ancient:

  $ hg history
  changeset:   0:acb14030fe0a
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     test
  

Verify that updating to revision 0 via commands.update() works properly

  $ cat <<EOF > update_to_rev0.py
  > from mercurial import commands, hg, ui as uimod
  > myui = uimod.ui.load()
  > repo = hg.repository(myui, path=b'.')
  > commands.update(myui, repo, rev=b"0")
  > EOF
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ "$PYTHON" ./update_to_rev0.py
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg identify -n
  0


Poke around at hashes:

  $ hg manifest --debug
  b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644   a

  $ hg cat a
  a

Verify should succeed:

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files

Repository root:

  $ hg root
  $TESTTMP/t
  $ hg log -l1 -T '{reporoot}\n'
  $TESTTMP/t
  $ hg root -Tjson | sed 's|\\\\|\\|g'
  [
   {
    "hgpath": "$TESTTMP/t/.hg",
    "reporoot": "$TESTTMP/t",
    "storepath": "$TESTTMP/t/.hg/store"
   }
  ]

At the end...

  $ cd ..

Status message redirection:

  $ hg init empty

 status messages are sent to stdout by default:

  $ hg outgoing -R t empty -Tjson 2>/dev/null
  comparing with empty
  searching for changes
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]

 which can be configured to send to stderr, so the output wouldn't be
 interleaved:

  $ cat <<'EOF' >> "$HGRCPATH"
  > [ui]
  > message-output = stderr
  > EOF
  $ hg outgoing -R t empty -Tjson 2>/dev/null
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]
  $ hg outgoing -R t empty -Tjson >/dev/null
  comparing with empty
  searching for changes

 this option should be turned off by HGPLAIN= since it may break scripting use:

  $ HGPLAIN= hg outgoing -R t empty -Tjson 2>/dev/null
  comparing with empty
  searching for changes
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]

 but still overridden by --config:

  $ HGPLAIN= hg outgoing -R t empty -Tjson --config ui.message-output=stderr \
  > 2>/dev/null
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]

Invalid ui.message-output option:

  $ hg log -R t --config ui.message-output=bad
  abort: invalid ui.message-output destination: bad
  [255]

Underlying message streams should be updated when ui.fout/ferr are set:

  $ cat <<'EOF' > capui.py
  > from mercurial import pycompat, registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'capui', norepo=True)
  > def capui(ui):
  >     out = ui.fout
  >     ui.fout = pycompat.bytesio()
  >     ui.status(b'status\n')
  >     ui.ferr = pycompat.bytesio()
  >     ui.warn(b'warn\n')
  >     out.write(b'stdout: %s' % ui.fout.getvalue())
  >     out.write(b'stderr: %s' % ui.ferr.getvalue())
  > EOF
  $ hg --config extensions.capui=capui.py --config ui.message-output=stdio capui
  stdout: status
  stderr: warn