view tests/test-mq-qimport.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)

  $ cat > writelines.py <<EOF
  > import sys
  > if sys.version_info[0] >= 3:
  >     encode = lambda x: x.encode('utf-8').decode('unicode_escape').encode('utf-8')
  > else:
  >     encode = lambda x: x.decode('string_escape')
  > path = sys.argv[1]
  > args = sys.argv[2:]
  > assert (len(args) % 2) == 0
  > 
  > f = open(path, 'wb')
  > for i in range(len(args) // 2):
  >    count, s = args[2 * i:2 * i + 2]
  >    count = int(count)
  >    s = encode(s)
  >    f.write(s * count)
  > f.close()
  > 
  > EOF
  > cat <<EOF >> $HGRCPATH
  > [extensions]
  > mq =
  > [diff]
  > git = 1
  > EOF
  $ hg init repo
  $ cd repo

qimport without file or revision

  $ hg qimport
  abort: no files or revisions specified
  [255]

qimport non-existing-file

  $ hg qimport non-existing-file
  abort: unable to read file non-existing-file
  [255]

qimport null revision

  $ hg qimport -r null
  abort: revision -1 is not mutable
  (see 'hg help phases' for details)
  [255]
  $ hg qseries

import email

  $ hg qimport --push -n email - <<EOF
  > From: Username in email <[e-mail]>
  > Subject: [PATCH] Message in email
  > Date: Fri, 02 Jan 1970 00:00:00 +0000
  > 
  > Text before patch.
  > 
  > # HG changeset patch
  > # User Username in patch <[e-mail]>
  > # Date 0 0
  > # Node ID 1a706973a7d84cb549823634a821d9bdf21c6220
  > # Parent  0000000000000000000000000000000000000000
  > First line of commit message.
  > 
  > More text in commit message.
  > --- confuse the diff detection
  > 
  > diff --git a/x b/x
  > new file mode 100644
  > --- /dev/null
  > +++ b/x
  > @@ -0,0 +1,1 @@
  > +new file
  > Text after patch.
  > 
  > EOF
  adding email to series file
  applying email
  now at: email

hg tip -v

  $ hg tip -v
  changeset:   0:1a706973a7d8
  tag:         email
  tag:         qbase
  tag:         qtip
  tag:         tip
  user:        Username in patch <[e-mail]>
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       x
  description:
  First line of commit message.
  
  More text in commit message.
  
  
  $ hg qpop
  popping email
  patch queue now empty
  $ hg qdelete email

import URL

  $ echo foo >> foo
  $ hg add foo
  $ hg diff > url.diff
  $ hg revert --no-backup foo
  $ rm foo

Under unix: file:///foobar/blah
Under windows: file:///c:/foobar/blah

  $ patchurl=`pwd | tr '\\\\' /`/url.diff
  $ expr "$patchurl" : "\/" > /dev/null || patchurl="/$patchurl"
  $ hg qimport file://"$patchurl"
  adding url.diff to series file
  $ rm url.diff
  $ hg qun
  url.diff

import patch that already exists

  $ echo foo2 >> foo
  $ hg add foo
  $ hg diff > ../url.diff
  $ hg revert --no-backup foo
  $ rm foo
  $ hg qimport ../url.diff
  abort: patch "url.diff" already exists
  [255]
  $ hg qpush
  applying url.diff
  now at: url.diff
  $ cat foo
  foo
  $ hg qpop
  popping url.diff
  patch queue now empty

qimport -f

  $ hg qimport -f ../url.diff
  adding url.diff to series file
  $ hg qpush
  applying url.diff
  now at: url.diff
  $ cat foo
  foo2
  $ hg qpop
  popping url.diff
  patch queue now empty

build diff with CRLF

  $ "$PYTHON" ../writelines.py b 5 'a\n' 5 'a\r\n'
  $ hg ci -Am addb
  adding b
  $ "$PYTHON" ../writelines.py b 2 'a\n' 10 'b\n' 2 'a\r\n'
  $ hg diff > b.diff
  $ hg up -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

qimport CRLF diff

  $ hg qimport b.diff
  adding b.diff to series file
  $ hg qpush
  applying b.diff
  now at: b.diff

try to import --push

  $ cat > appendfoo.diff <<EOF
  > append foo
  > 
  > diff -r 07f494440405 -r 261500830e46 baz
  > --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  > +++ b/baz	Thu Jan 01 00:00:00 1970 +0000
  > @@ -0,0 +1,1 @@
  > +foo
  > EOF

  $ cat > appendbar.diff <<EOF
  > append bar
  > 
  > diff -r 07f494440405 -r 261500830e46 baz
  > --- a/baz	Thu Jan 01 00:00:00 1970 +0000
  > +++ b/baz	Thu Jan 01 00:00:00 1970 +0000
  > @@ -1,1 +1,2 @@
  >  foo
  > +bar
  > EOF

  $ hg qimport --push appendfoo.diff appendbar.diff
  adding appendfoo.diff to series file
  adding appendbar.diff to series file
  applying appendfoo.diff
  applying appendbar.diff
  now at: appendbar.diff
  $ hg qfin -a
  patch b.diff finalized without changeset message
  $ touch .hg/patches/append_foo
  $ hg qimport -r 'p1(.)::'
  $ hg qapplied
  append_foo__1
  append_bar
  $ hg qfin -a
  $ rm .hg/patches/append_foo
  $ hg qimport -r 'p1(.)::' -P
  $ hg qpop -a
  popping append_bar
  popping append_foo
  patch queue now empty
  $ hg qdel append_foo
  $ hg qdel -k append_bar

qimport -e

  $ hg qimport -e append_bar
  adding append_bar to series file
  $ hg qdel -k append_bar

qimport -e --name newname oldexisitingpatch

  $ hg qimport -e --name this-name-is-better append_bar
  renaming append_bar to this-name-is-better
  adding this-name-is-better to series file
  $ hg qser
  this-name-is-better
  url.diff

qimport -e --name without --force

  $ cp .hg/patches/this-name-is-better .hg/patches/3.diff
  $ hg qimport -e --name this-name-is-better 3.diff
  abort: patch "this-name-is-better" already exists
  [255]
  $ hg qser
  this-name-is-better
  url.diff

qimport -e --name with --force

  $ hg qimport --force -e --name this-name-is-better 3.diff
  renaming 3.diff to this-name-is-better
  adding this-name-is-better to series file
  $ hg qser
  this-name-is-better
  url.diff

import patch of bad filename

  $ touch '../ bad.diff'
  $ hg qimport '../ bad.diff'
  abort: patch name cannot begin or end with whitespace
  [255]
  $ touch '.hg/patches/ bad.diff'
  $ hg qimport -e ' bad.diff'
  abort: patch name cannot begin or end with whitespace
  [255]

qimport with bad name, should abort before reading file

  $ hg qimport non-existent-file --name .hg
  abort: patch name cannot begin with ".hg"
  [255]
  $ hg qimport non-existent-file --name ' foo'
  abort: patch name cannot begin or end with whitespace
  [255]
  $ hg qimport non-existent-file --name 'foo '
  abort: patch name cannot begin or end with whitespace
  [255]

qimport http:// patch with leading slashes in url

set up hgweb

  $ cd ..
  $ hg init served
  $ cd served
  $ echo a > a
  $ hg ci -Am patch
  adding a
  $ hg serve -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
  $ cat hg.pid >> $DAEMON_PIDS

  $ cd ../repo
  $ hg qimport http://localhost:$HGPORT/raw-rev/0///
  adding 0 to series file

check qimport phase:

  $ hg -q qpush
  now at: 0
  $ hg phase qparent
  1: draft
  $ hg qimport -r qparent
  $ hg phase qbase
  1: draft
  $ hg qfinish qbase
  $ echo '[mq]' >> $HGRCPATH
  $ echo 'secret=true' >> $HGRCPATH
  $ hg qimport -r qparent
  $ hg phase qbase
  1: secret

  $ cd ..

  $ killdaemons.py

check patch name generation for non-alpha-numeric summary line

  $ cd repo

  $ hg qpop -a -q
  patch queue now empty
  $ hg qseries -v
  0 U imported_patch_b_diff
  1 U 0
  2 U this-name-is-better
  3 U url.diff

  $ echo bb >> b
  $ hg commit -m '==++--=='

  $ hg qimport -r tip
  $ hg qseries -v
  0 A 1.diff
  1 U imported_patch_b_diff
  2 U 0
  3 U this-name-is-better
  4 U url.diff

check reserved patch names

  $ hg qpop -qa
  patch queue now empty
  $ echo >> b
  $ hg commit -m 'status'
  $ echo >> b
  $ hg commit -m '.'
  $ echo >> b
  $ hg commit -m 'taken'
  $ mkdir .hg/patches/taken
  $ touch .hg/patches/taken__1
  $ hg qimport -r -3::
  $ hg qap
  1.diff__1
  2.diff
  taken__2

check very long patch name

  $ hg qpop -qa
  patch queue now empty
  $ echo >> b
  $ hg commit -m 'abcdefghi pqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghi pqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghi pqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghi pqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghi pqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghi pqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
  $ hg qimport -r .
  $ hg qap
  abcdefghi_pqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghi_pqrstuvwxyzabcdefg