view tests/test-config.t @ 38732:be4984261611

merge: mark file gets as not thread safe (issue5933)

In default installs, this has the effect of disabling the thread-based
worker on Windows when manifesting files in the working directory. My
measurements have shown that with revlog-based repositories, Mercurial
spends a lot of CPU time in revlog code resolving file data. This ends
up incurring a lot of context switching across threads and slows down
`hg update` operations when going from an empty working directory to
the tip of the repo.

On mozilla-unified (246,351 files) on an i7-6700K (4+4 CPUs):

before: 487s wall
after:  360s wall (equivalent to worker.enabled=false)
cpus=2: 379s wall

Even with only 2 threads, the thread pool is still slower.

The introduction of the thread-based worker (02b36e860e0b) states that
it resulted in a "~50%" speedup for `hg sparse --enable-profile` and
`hg sparse --disable-profile`. This disagrees with my measurement
above. I theorize a few reasons for this:

1) Removal of files from the working directory is I/O - not CPU - bound
   and should benefit from a thread pool (unless I/O is insanely fast
   and the GIL release is near instantaneous). So tests like `hg sparse
   --enable-profile` may exercise deletion throughput and aren't good
   benchmarks for worker tasks that are CPU heavy.
2) The patch was authored by someone at Facebook. The results were
   likely measured against a repository using remotefilelog. And I
   believe that revision retrieval during working directory updates with
   remotefilelog will often use a remote store, thus being I/O and not
   CPU bound. This probably resulted in an overstated performance gain.

Since there appears to be a need to enable the thread-based worker with
some stores, I've made the flagging of file gets as thread safe
configurable. I've made it experimental because I don't want to formalize
a boolean flag for this option and because this attribute is best
captured against the store implementation. But we don't have a proper
store API for this yet. I'd rather cross this bridge later.

It is possible there are revlog-based repositories that do benefit from
a thread-based worker. I didn't do very comprehensive testing. If there
are, we may want to devise a more proper algorithm for whether to use
the thread-based worker, including possibly config options to limit the
number of threads to use. But until I see evidence that justifies
complexity, simplicity wins.

Differential Revision: https://phab.mercurial-scm.org/D3963

hide outer repo
  $ hg init

Invalid syntax: no value

  $ cat > .hg/hgrc << EOF
  > novaluekey
  > EOF
  $ hg showconfig
  hg: parse error at $TESTTMP/.hg/hgrc:1: novaluekey
  [255]

Invalid syntax: no key

  $ cat > .hg/hgrc << EOF
  > =nokeyvalue
  > EOF
  $ hg showconfig
  hg: parse error at $TESTTMP/.hg/hgrc:1: =nokeyvalue
  [255]

Test hint about invalid syntax from leading white space

  $ cat > .hg/hgrc << EOF
  >  key=value
  > EOF
  $ hg showconfig
  hg: parse error at $TESTTMP/.hg/hgrc:1:  key=value
  unexpected leading whitespace
  [255]

  $ cat > .hg/hgrc << EOF
  >  [section]
  > key=value
  > EOF
  $ hg showconfig
  hg: parse error at $TESTTMP/.hg/hgrc:1:  [section]
  unexpected leading whitespace
  [255]

Reset hgrc

  $ echo > .hg/hgrc

Test case sensitive configuration

  $ cat <<EOF >> $HGRCPATH
  > [Section]
  > KeY = Case Sensitive
  > key = lower case
  > EOF

  $ hg showconfig Section
  Section.KeY=Case Sensitive
  Section.key=lower case

  $ hg showconfig Section -Tjson
  [
   {
    "name": "Section.KeY",
    "source": "*.hgrc:*", (glob)
    "value": "Case Sensitive"
   },
   {
    "name": "Section.key",
    "source": "*.hgrc:*", (glob)
    "value": "lower case"
   }
  ]
  $ hg showconfig Section.KeY -Tjson
  [
   {
    "name": "Section.KeY",
    "source": "*.hgrc:*", (glob)
    "value": "Case Sensitive"
   }
  ]
  $ hg showconfig -Tjson | tail -7
   },
   {
    "name": "*", (glob)
    "source": "*", (glob)
    "value": "*" (glob)
   }
  ]

Test empty config source:

  $ cat <<EOF > emptysource.py
  > def reposetup(ui, repo):
  >     ui.setconfig(b'empty', b'source', b'value')
  > EOF
  $ cp .hg/hgrc .hg/hgrc.orig
  $ cat <<EOF >> .hg/hgrc
  > [extensions]
  > emptysource = `pwd`/emptysource.py
  > EOF

  $ hg config --debug empty.source
  read config from: * (glob)
  none: value
  $ hg config empty.source -Tjson
  [
   {
    "name": "empty.source",
    "source": "",
    "value": "value"
   }
  ]

  $ cp .hg/hgrc.orig .hg/hgrc

Test "%unset"

  $ cat >> $HGRCPATH <<EOF
  > [unsettest]
  > local-hgrcpath = should be unset (HGRCPATH)
  > %unset local-hgrcpath
  > 
  > global = should be unset (HGRCPATH)
  > 
  > both = should be unset (HGRCPATH)
  > 
  > set-after-unset = should be unset (HGRCPATH)
  > EOF

  $ cat >> .hg/hgrc <<EOF
  > [unsettest]
  > local-hgrc = should be unset (.hg/hgrc)
  > %unset local-hgrc
  > 
  > %unset global
  > 
  > both = should be unset (.hg/hgrc)
  > %unset both
  > 
  > set-after-unset = should be unset (.hg/hgrc)
  > %unset set-after-unset
  > set-after-unset = should be set (.hg/hgrc)
  > EOF

  $ hg showconfig unsettest
  unsettest.set-after-unset=should be set (.hg/hgrc)

Test exit code when no config matches

  $ hg config Section.idontexist
  [1]

sub-options in [paths] aren't expanded

  $ cat > .hg/hgrc << EOF
  > [paths]
  > foo = ~/foo
  > foo:suboption = ~/foo
  > EOF

  $ hg showconfig paths
  paths.foo:suboption=~/foo
  paths.foo=$TESTTMP/foo

edit failure

  $ HGEDITOR=false hg config --edit
  abort: edit failed: false exited with status 1
  [255]

config affected by environment variables

  $ EDITOR=e1 VISUAL=e2 hg config --debug | grep 'ui\.editor'
  $VISUAL: ui.editor=e2

  $ VISUAL=e2 hg config --debug --config ui.editor=e3 | grep 'ui\.editor'
  --config: ui.editor=e3

  $ PAGER=p1 hg config --debug | grep 'pager\.pager'
  $PAGER: pager.pager=p1

  $ PAGER=p1 hg config --debug --config pager.pager=p2 | grep 'pager\.pager'
  --config: pager.pager=p2

verify that aliases are evaluated as well

  $ hg init aliastest
  $ cd aliastest
  $ cat > .hg/hgrc << EOF
  > [ui]
  > user = repo user
  > EOF
  $ touch index
  $ unset HGUSER
  $ hg ci -Am test
  adding index
  $ hg log --template '{author}\n'
  repo user
  $ cd ..

alias has lower priority

  $ hg init aliaspriority
  $ cd aliaspriority
  $ cat > .hg/hgrc << EOF
  > [ui]
  > user = alias user
  > username = repo user
  > EOF
  $ touch index
  $ unset HGUSER
  $ hg ci -Am test
  adding index
  $ hg log --template '{author}\n'
  repo user
  $ cd ..