view tests/test-init.t @ 44950:f9734b2d59cc

py3: make stdout line-buffered if connected to a TTY

Status messages that are to be shown on the terminal should be written to the
file descriptor before anything further is done, to keep the user updated.

One common way to achieve this is to make stdout line-buffered if it is
connected to a TTY. This is done on Python 2 (except on Windows, where libc,
which the CPython 2 streams depend on, does not properly support this).

Python 3 rolls it own I/O streams. On Python 3, buffered binary streams can't be
set line-buffered. The previous code (added in 227ba1afcb65) incorrectly
assumed that on Python 3, pycompat.stdout (sys.stdout.buffer) is already
line-buffered. However the interpreter initializes it with a block-buffered
stream or an unbuffered stream (when the -u option or the PYTHONUNBUFFERED
environment variable is set), never with a line-buffered stream.

One example where the current behavior is unacceptable is when running
`hg pull https://www.mercurial-scm.org/repo/hg` on Python 3, where the line
"pulling from https://www.mercurial-scm.org/repo/hg" does not appear on the
terminal before the hg process blocks while waiting for the server.

Various approaches to fix this problem are possible, including:

1. Weaken the contract of procutil.stdout to not give any guarantees about
   buffering behavior. In this case, users of procutil.stdout need to be
   changed to do enough flushes. In particular,
  1. either ui must insert enough flushes for ui.write() and friends, or
  2. ui.write() and friends get split into flushing and fully buffered
     methods, or
  3. users of ui.write() and friends must flush explicitly.
2. Make stdout unbuffered.
3. Make stdout line-buffered. Since Python 3 does not natively support that for
   binary streams, we must implement it ourselves.

(2.) is problematic because using unbuffered I/O changes the performance
characteristics significantly compared to line-buffered (which is used on
Python 2) and this would be a regression.

(1.2.) and (1.3) are a substantial amount of work. It’s unclear whether the
added complexity would be justified, given that raw performance doesn’t matter
that much when writing to a terminal much faster than the user could read it.

(1.1.) pushes complexity into the ui class instead of separating the concern of
how stdout is buffered. Other users of procutil.stdout would still need to take
care of the flushes.

This patch implements (3.). The general performance considerations are very
similar to (1.1.). The extra method invocation and method forwarding add a
little more overhead if the class is used. In exchange, it doesn’t add overhead
if not used.


For the benchmarks, I compared the previous implementation (incorrect on Python
3), (1.1.), (3.) and (2.). The command was chosen so that the streams were
configured as if they were writing to a TTY, but actually write to a pager,
which is also the default:
HGRCPATH=/dev/null python3 ./hg --cwd ~/vcs/mozilla-central --time --pager yes --config pager.pager='cat > /dev/null' status --all

previous:
time: real 7.880 secs (user 7.290+0.050 sys 0.580+0.170)
time: real 7.830 secs (user 7.220+0.070 sys 0.590+0.140)
time: real 7.800 secs (user 7.210+0.050 sys 0.570+0.170)

(1.1.) using Yuya Nishihara’s patch:
time: real 9.860 secs (user 8.670+0.350 sys 1.160+0.830)
time: real 9.540 secs (user 8.430+0.370 sys 1.100+0.770)
time: real 9.830 secs (user 8.630+0.370 sys 1.180+0.840)

(3.) using this patch:
time: real 9.580 secs (user 8.480+0.350 sys 1.090+0.770)
time: real 9.670 secs (user 8.480+0.330 sys 1.170+0.860)
time: real 9.640 secs (user 8.500+0.350 sys 1.130+0.810)

(2.) using a previous patch by me:
time: real 10.480 secs (user 8.850+0.720 sys 1.590+1.500)
time: real 10.490 secs (user 8.750+0.750 sys 1.710+1.470)
time: real 10.240 secs (user 8.600+0.700 sys 1.590+1.510)


As expected, there’s no difference on Python 2, as exactly the same code paths
are used:

previous:
time: real 6.950 secs (user 5.870+0.330 sys 1.070+0.770)
time: real 7.040 secs (user 6.040+0.360 sys 0.980+0.750)
time: real 7.070 secs (user 5.950+0.360 sys 1.100+0.760)

this patch:
time: real 7.010 secs (user 5.900+0.390 sys 1.070+0.730)
time: real 7.000 secs (user 5.850+0.350 sys 1.120+0.760)
time: real 7.000 secs (user 5.790+0.380 sys 1.170+0.710)

This test tries to exercise the ssh functionality with a dummy script

  $ checknewrepo()
  > {
  >    name=$1
  >    if [ -d "$name"/.hg/store ]; then
  >    echo store created
  >    fi
  >    if [ -f "$name"/.hg/00changelog.i ]; then
  >    echo 00changelog.i created
  >    fi
  >    cat "$name"/.hg/requires
  > }

creating 'local'

  $ hg init local
  $ checknewrepo local
  store created
  00changelog.i created
  dotencode
  fncache
  generaldelta
  revlogv1
  sparserevlog
  store
  testonly-simplestore (reposimplestore !)
  $ echo this > local/foo
  $ hg ci --cwd local -A -m "init"
  adding foo

test custom revlog chunk cache sizes

  $ hg --config format.chunkcachesize=0 log -R local -pv
  abort: revlog chunk cache size 0 is not greater than 0!
  [255]
  $ hg --config format.chunkcachesize=1023 log -R local -pv
  abort: revlog chunk cache size 1023 is not a power of 2!
  [255]
  $ hg --config format.chunkcachesize=1024 log -R local -pv
  changeset:   0:08b9e9f63b32
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       foo
  description:
  init
  
  
  diff -r 000000000000 -r 08b9e9f63b32 foo
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +this
  

creating repo with format.usestore=false

  $ hg --config format.usestore=false init old
  $ checknewrepo old
  generaldelta
  revlogv1
  testonly-simplestore (reposimplestore !)
  sparserevlog

creating repo with format.usefncache=false

  $ hg --config format.usefncache=false init old2
  $ checknewrepo old2
  store created
  00changelog.i created
  generaldelta
  revlogv1
  sparserevlog
  store
  testonly-simplestore (reposimplestore !)

creating repo with format.dotencode=false

  $ hg --config format.dotencode=false init old3
  $ checknewrepo old3
  store created
  00changelog.i created
  fncache
  generaldelta
  revlogv1
  sparserevlog
  store
  testonly-simplestore (reposimplestore !)

creating repo with format.dotencode=false

  $ hg --config format.generaldelta=false --config format.usegeneraldelta=false --config format.sparse-revlog=no init old4
  $ checknewrepo old4
  store created
  00changelog.i created
  dotencode
  fncache
  revlogv1
  store
  testonly-simplestore (reposimplestore !)

test failure

  $ hg init local
  abort: repository local already exists!
  [255]

init+push to remote2

  $ hg init -e "\"$PYTHON\" \"$TESTDIR/dummyssh\"" ssh://user@dummy/remote2
  $ hg incoming -R remote2 local
  comparing with local
  changeset:   0:08b9e9f63b32
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     init
  

  $ hg push -R local -e "\"$PYTHON\" \"$TESTDIR/dummyssh\"" ssh://user@dummy/remote2
  pushing to ssh://user@dummy/remote2
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files

clone to remote1

  $ hg clone -e "\"$PYTHON\" \"$TESTDIR/dummyssh\"" local ssh://user@dummy/remote1
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files

The largefiles extension doesn't crash
  $ hg clone -e "\"$PYTHON\" \"$TESTDIR/dummyssh\"" local ssh://user@dummy/remotelf --config extensions.largefiles=
  The fsmonitor extension is incompatible with the largefiles extension and has been disabled. (fsmonitor !)
  The fsmonitor extension is incompatible with the largefiles extension and has been disabled. (fsmonitor !)
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files

init to existing repo

  $ hg init -e "\"$PYTHON\" \"$TESTDIR/dummyssh\"" ssh://user@dummy/remote1
  abort: repository remote1 already exists!
  abort: could not create remote repo!
  [255]

clone to existing repo

  $ hg clone -e "\"$PYTHON\" \"$TESTDIR/dummyssh\"" local ssh://user@dummy/remote1
  abort: repository remote1 already exists!
  abort: could not create remote repo!
  [255]

output of dummyssh

  $ cat dummylog
  Got arguments 1:user@dummy 2:hg init remote2
  Got arguments 1:user@dummy 2:hg -R remote2 serve --stdio
  Got arguments 1:user@dummy 2:hg -R remote2 serve --stdio
  Got arguments 1:user@dummy 2:hg init remote1
  Got arguments 1:user@dummy 2:hg -R remote1 serve --stdio
  Got arguments 1:user@dummy 2:hg init remotelf
  Got arguments 1:user@dummy 2:hg -R remotelf serve --stdio
  Got arguments 1:user@dummy 2:hg init remote1
  Got arguments 1:user@dummy 2:hg init remote1

comparing repositories

  $ hg tip -q -R local
  0:08b9e9f63b32
  $ hg tip -q -R remote1
  0:08b9e9f63b32
  $ hg tip -q -R remote2
  0:08b9e9f63b32

check names for repositories (clashes with URL schemes, special chars)

  $ for i in bundle file hg http https old-http ssh static-http "with space"; do
  >   printf "hg init \"$i\"... "
  >   hg init "$i"
  >   test -d "$i" -a -d "$i/.hg" && echo "ok" || echo "failed"
  > done
  hg init "bundle"... ok
  hg init "file"... ok
  hg init "hg"... ok
  hg init "http"... ok
  hg init "https"... ok
  hg init "old-http"... ok
  hg init "ssh"... ok
  hg init "static-http"... ok
  hg init "with space"... ok
#if eol-in-paths
/* " " is not a valid name for a directory on Windows */
  $ hg init " "
  $ test -d " "
  $ test -d " /.hg"
#endif

creating 'local/sub/repo'

  $ hg init local/sub/repo
  $ checknewrepo local/sub/repo
  store created
  00changelog.i created
  dotencode
  fncache
  generaldelta
  revlogv1
  sparserevlog
  store
  testonly-simplestore (reposimplestore !)

prepare test of init of url configured from paths

  $ echo '[paths]' >> $HGRCPATH
  $ echo "somewhere = `pwd`/url from paths" >> $HGRCPATH
  $ echo "elsewhere = `pwd`/another paths url" >> $HGRCPATH

init should (for consistency with clone) expand the url

  $ hg init somewhere
  $ checknewrepo "url from paths"
  store created
  00changelog.i created
  dotencode
  fncache
  generaldelta
  revlogv1
  sparserevlog
  store
  testonly-simplestore (reposimplestore !)

verify that clone also expand urls

  $ hg clone somewhere elsewhere
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ checknewrepo "another paths url"
  store created
  00changelog.i created
  dotencode
  fncache
  generaldelta
  revlogv1
  sparserevlog
  store
  testonly-simplestore (reposimplestore !)

clone bookmarks

  $ hg -R local bookmark test
  $ hg -R local bookmarks
   * test                      0:08b9e9f63b32
  $ hg clone -e "\"$PYTHON\" \"$TESTDIR/dummyssh\"" local ssh://user@dummy/remote-bookmarks
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  exporting bookmark test
  $ hg -R remote-bookmarks bookmarks
     test                      0:08b9e9f63b32

Check format constraint
-----------------------

  $ hg init issue6056 --config format.usegeneraldelta=0 --config format.sparse-revlog=0
  $ cd issue6056
  $ echo foo > 1
  $ echo foo > 2
  $ echo foo > 3
  $ echo foo > 4
  $ echo foo > 5
  $ hg add *

Build a bogus repository (sparserevlog without general delta)

  $ hg commit -m 'initial changesets'
  $ echo 'sparserevlog' >> .hg/requires
  $ for x in `$TESTDIR/seq.py 100`; do
  >     echo $x >> `expr $x % 5 + 1`
  >     hg commit -m $x
  > done
  $ cd ..