view tests/test-mq-header-from.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)

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH
  $ echo "[diff]" >> $HGRCPATH
  $ echo "nodates=true" >> $HGRCPATH
  $ catlog() {
  >     cat .hg/patches/$1.patch | sed -e "s/^diff \-r [0-9a-f]* /diff -r ... /" \
  >                                    -e "s/^\(# Parent \).*/\1/"
  >     hg log --template "{rev}: {node|short} {desc} - {author}\n"
  > }
  $ runtest() {
  >     echo ==== init
  >     hg init a
  >     cd a
  >     hg qinit
  > 
  > 
  >     echo ==== qnew -U
  >     hg qnew -U 1.patch
  >     catlog 1
  > 
  >     echo ==== qref
  >     echo "1" >1
  >     hg add
  >     hg qref
  >     catlog 1
  > 
  >     echo ==== qref -u
  >     hg qref -u mary
  >     catlog 1
  > 
  >     echo ==== qnew
  >     hg qnew 2.patch
  >     echo "2" >2
  >     hg add
  >     hg qref
  >     catlog 2
  > 
  >     echo ==== qref -u
  >     hg qref -u jane
  >     catlog 2
  > 
  > 
  >     echo ==== qnew -U -m
  >     hg qnew -U -m "Three" 3.patch
  >     catlog 3
  > 
  >     echo ==== qref
  >     echo "3" >3
  >     hg add
  >     hg qref
  >     catlog 3
  > 
  >     echo ==== qref -m
  >     hg qref -m "Drei"
  >     catlog 3
  > 
  >     echo ==== qref -u
  >     hg qref -u mary
  >     catlog 3
  > 
  >     echo ==== qref -u -m
  >     hg qref -u maria -m "Three (again)"
  >     catlog 3
  > 
  >     echo ==== qnew -m
  >     hg qnew -m "Four" 4.patch
  >     echo "4" >4of t
  >     hg add
  >     hg qref
  >     catlog 4
  > 
  >     echo ==== qref -u
  >     hg qref -u jane
  >     catlog 4
  > 
  > 
  >     echo ==== qnew with HG header
  >     hg qnew --config 'mq.plain=true' 5.patch
  >     hg qpop
  >     echo "# HG changeset patch" >>.hg/patches/5.patch
  >     echo "# User johndoe" >>.hg/patches/5.patch
  >     hg qpush 2>&1 | grep 'now at'
  >     catlog 5
  > 
  >     echo ==== hg qref
  >     echo "5" >5
  >     hg add
  >     hg qref
  >     catlog 5
  > 
  >     echo ==== hg qref -U
  >     hg qref -U
  >     catlog 5
  > 
  >     echo ==== hg qref -u
  >     hg qref -u johndeere
  >     catlog 5
  > 
  > 
  >     echo ==== qnew with plain header
  >     hg qnew --config 'mq.plain=true' -U 6.patch
  >     hg qpop
  >     hg qpush 2>&1 | grep 'now at'
  >     catlog 6
  > 
  >     echo ==== hg qref
  >     echo "6" >6
  >     hg add
  >     hg qref
  >     catlog 6
  > 
  >     echo ==== hg qref -U
  >     hg qref -U
  >     catlog 6
  > 
  >     echo ==== hg qref -u
  >     hg qref -u johndeere
  >     catlog 6
  > 
  > 
  >     echo ==== "qpop -a / qpush -a"
  >     hg qpop -a
  >     hg qpush -a
  >     hg log --template "{rev}: {node|short} {desc} - {author}\n"
  > }

======= plain headers

  $ echo "[mq]" >> $HGRCPATH
  $ echo "plain=true" >> $HGRCPATH
  $ mkdir sandbox
  $ (cd sandbox ; runtest)
  ==== init
  ==== qnew -U
  From: test
  
  0: a054644889e5 [mq]: 1.patch - test
  ==== qref
  adding 1
  From: test
  
  diff -r ... 1
  --- /dev/null
  +++ b/1
  @@ -0,0 +1,1 @@
  +1
  0: 2905f1e46ee0 [mq]: 1.patch - test
  ==== qref -u
  From: mary
  
  diff -r ... 1
  --- /dev/null
  +++ b/1
  @@ -0,0 +1,1 @@
  +1
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew
  adding 2
  diff -r ... 2
  --- /dev/null
  +++ b/2
  @@ -0,0 +1,1 @@
  +2
  1: 527f98a12a7a [mq]: 2.patch - test
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u
  From: jane
  
  diff -r ... 2
  --- /dev/null
  +++ b/2
  @@ -0,0 +1,1 @@
  +2
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew -U -m
  From: test
  
  Three
  
  2: 0ffa16a9088e Three - test
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref
  adding 3
  From: test
  
  Three
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: 83f1290c6086 Three - test
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -m
  From: test
  
  Drei
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: b0d856328d4d Drei - test
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u
  From: mary
  
  Drei
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: bb9d4b28e6a6 Drei - mary
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u -m
  From: maria
  
  Three (again)
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew -m
  adding 4of
  Four
  
  diff -r ... 4of
  --- /dev/null
  +++ b/4of
  @@ -0,0 +1,1 @@
  +4 t
  3: b9f922d0da40 Four - test
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u
  From: jane
  
  Four
  
  diff -r ... 4of
  --- /dev/null
  +++ b/4of
  @@ -0,0 +1,1 @@
  +4 t
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew with HG header
  popping 5.patch
  now at: 4.patch
  now at: 5.patch
  # HG changeset patch
  # User johndoe
  4: 72bc4a0467ef imported patch 5.patch - johndoe
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref
  adding 5
  # HG changeset patch
  # User johndoe
  # Parent 
  
  diff -r ... 5
  --- /dev/null
  +++ b/5
  @@ -0,0 +1,1 @@
  +5
  4: ff5c06112e5a [mq]: 5.patch - johndoe
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -U
  # HG changeset patch
  # User test
  # Parent 
  
  diff -r ... 5
  --- /dev/null
  +++ b/5
  @@ -0,0 +1,1 @@
  +5
  4: c947416c22b1 [mq]: 5.patch - test
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -u
  # HG changeset patch
  # User johndeere
  # Parent 
  
  diff -r ... 5
  --- /dev/null
  +++ b/5
  @@ -0,0 +1,1 @@
  +5
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew with plain header
  popping 6.patch
  now at: 5.patch
  now at: 6.patch
  From: test
  
  5: 7825a18ec839 imported patch 6.patch - test
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref
  adding 6
  From: test
  
  diff -r ... 6
  --- /dev/null
  +++ b/6
  @@ -0,0 +1,1 @@
  +6
  5: 09d19592680d [mq]: 6.patch - test
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -U
  From: test
  
  diff -r ... 6
  --- /dev/null
  +++ b/6
  @@ -0,0 +1,1 @@
  +6
  5: 09d19592680d [mq]: 6.patch - test
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -u
  From: johndeere
  
  diff -r ... 6
  --- /dev/null
  +++ b/6
  @@ -0,0 +1,1 @@
  +6
  5: 32641ee07196 [mq]: 6.patch - johndeere
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qpop -a / qpush -a
  popping 6.patch
  popping 5.patch
  popping 4.patch
  popping 3.patch
  popping 2.patch
  popping 1.patch
  patch queue now empty
  applying 1.patch
  applying 2.patch
  applying 3.patch
  applying 4.patch
  applying 5.patch
  applying 6.patch
  now at: 6.patch
  5: 1fb083c80457 imported patch 6.patch - johndeere
  4: 7e96e969691d imported patch 5.patch - johndeere
  3: c7147533d3cd Four - jane
  2: b383d04401ea Three (again) - maria
  1: fac2da4efc3c imported patch 2.patch - jane
  0: b6e237e8771b imported patch 1.patch - mary
  $ rm -r sandbox

======= hg headers

  $ echo "plain=false" >> $HGRCPATH
  $ mkdir sandbox
  $ (cd sandbox ; runtest)
  ==== init
  ==== qnew -U
  # HG changeset patch
  # User test
  # Parent 
  
  0: a054644889e5 [mq]: 1.patch - test
  ==== qref
  adding 1
  # HG changeset patch
  # User test
  # Parent 
  
  diff -r ... 1
  --- /dev/null
  +++ b/1
  @@ -0,0 +1,1 @@
  +1
  0: 2905f1e46ee0 [mq]: 1.patch - test
  ==== qref -u
  # HG changeset patch
  # User mary
  # Parent 
  
  diff -r ... 1
  --- /dev/null
  +++ b/1
  @@ -0,0 +1,1 @@
  +1
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew
  adding 2
  # HG changeset patch
  # Parent 
  
  diff -r ... 2
  --- /dev/null
  +++ b/2
  @@ -0,0 +1,1 @@
  +2
  1: 527f98a12a7a [mq]: 2.patch - test
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u
  # HG changeset patch
  # User jane
  # Parent 
  
  diff -r ... 2
  --- /dev/null
  +++ b/2
  @@ -0,0 +1,1 @@
  +2
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew -U -m
  # HG changeset patch
  # User test
  # Parent 
  Three
  
  2: 0ffa16a9088e Three - test
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref
  adding 3
  # HG changeset patch
  # User test
  # Parent 
  Three
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: 83f1290c6086 Three - test
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -m
  # HG changeset patch
  # User test
  # Parent 
  Drei
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: b0d856328d4d Drei - test
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u
  # HG changeset patch
  # User mary
  # Parent 
  Drei
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: bb9d4b28e6a6 Drei - mary
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u -m
  # HG changeset patch
  # User maria
  # Parent 
  Three (again)
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew -m
  adding 4of
  # HG changeset patch
  # Parent 
  Four
  
  diff -r ... 4of
  --- /dev/null
  +++ b/4of
  @@ -0,0 +1,1 @@
  +4 t
  3: b9f922d0da40 Four - test
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u
  # HG changeset patch
  # User jane
  # Parent 
  Four
  
  diff -r ... 4of
  --- /dev/null
  +++ b/4of
  @@ -0,0 +1,1 @@
  +4 t
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew with HG header
  popping 5.patch
  now at: 4.patch
  now at: 5.patch
  # HG changeset patch
  # User johndoe
  4: 72bc4a0467ef imported patch 5.patch - johndoe
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref
  adding 5
  # HG changeset patch
  # User johndoe
  # Parent 
  
  diff -r ... 5
  --- /dev/null
  +++ b/5
  @@ -0,0 +1,1 @@
  +5
  4: ff5c06112e5a [mq]: 5.patch - johndoe
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -U
  # HG changeset patch
  # User test
  # Parent 
  
  diff -r ... 5
  --- /dev/null
  +++ b/5
  @@ -0,0 +1,1 @@
  +5
  4: c947416c22b1 [mq]: 5.patch - test
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -u
  # HG changeset patch
  # User johndeere
  # Parent 
  
  diff -r ... 5
  --- /dev/null
  +++ b/5
  @@ -0,0 +1,1 @@
  +5
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew with plain header
  popping 6.patch
  now at: 5.patch
  now at: 6.patch
  From: test
  
  5: 7825a18ec839 imported patch 6.patch - test
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref
  adding 6
  From: test
  
  diff -r ... 6
  --- /dev/null
  +++ b/6
  @@ -0,0 +1,1 @@
  +6
  5: 09d19592680d [mq]: 6.patch - test
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -U
  From: test
  
  diff -r ... 6
  --- /dev/null
  +++ b/6
  @@ -0,0 +1,1 @@
  +6
  5: 09d19592680d [mq]: 6.patch - test
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -u
  From: johndeere
  
  diff -r ... 6
  --- /dev/null
  +++ b/6
  @@ -0,0 +1,1 @@
  +6
  5: 32641ee07196 [mq]: 6.patch - johndeere
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qpop -a / qpush -a
  popping 6.patch
  popping 5.patch
  popping 4.patch
  popping 3.patch
  popping 2.patch
  popping 1.patch
  patch queue now empty
  applying 1.patch
  applying 2.patch
  applying 3.patch
  applying 4.patch
  applying 5.patch
  applying 6.patch
  now at: 6.patch
  5: 1fb083c80457 imported patch 6.patch - johndeere
  4: 7e96e969691d imported patch 5.patch - johndeere
  3: c7147533d3cd Four - jane
  2: b383d04401ea Three (again) - maria
  1: fac2da4efc3c imported patch 2.patch - jane
  0: b6e237e8771b imported patch 1.patch - mary
  $ rm -r sandbox
  $ runtest
  ==== init
  ==== qnew -U
  # HG changeset patch
  # User test
  # Parent 
  
  0: a054644889e5 [mq]: 1.patch - test
  ==== qref
  adding 1
  # HG changeset patch
  # User test
  # Parent 
  
  diff -r ... 1
  --- /dev/null
  +++ b/1
  @@ -0,0 +1,1 @@
  +1
  0: 2905f1e46ee0 [mq]: 1.patch - test
  ==== qref -u
  # HG changeset patch
  # User mary
  # Parent 
  
  diff -r ... 1
  --- /dev/null
  +++ b/1
  @@ -0,0 +1,1 @@
  +1
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew
  adding 2
  # HG changeset patch
  # Parent 
  
  diff -r ... 2
  --- /dev/null
  +++ b/2
  @@ -0,0 +1,1 @@
  +2
  1: 527f98a12a7a [mq]: 2.patch - test
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u
  # HG changeset patch
  # User jane
  # Parent 
  
  diff -r ... 2
  --- /dev/null
  +++ b/2
  @@ -0,0 +1,1 @@
  +2
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew -U -m
  # HG changeset patch
  # User test
  # Parent 
  Three
  
  2: 0ffa16a9088e Three - test
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref
  adding 3
  # HG changeset patch
  # User test
  # Parent 
  Three
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: 83f1290c6086 Three - test
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -m
  # HG changeset patch
  # User test
  # Parent 
  Drei
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: b0d856328d4d Drei - test
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u
  # HG changeset patch
  # User mary
  # Parent 
  Drei
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: bb9d4b28e6a6 Drei - mary
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u -m
  # HG changeset patch
  # User maria
  # Parent 
  Three (again)
  
  diff -r ... 3
  --- /dev/null
  +++ b/3
  @@ -0,0 +1,1 @@
  +3
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew -m
  adding 4of
  # HG changeset patch
  # Parent 
  Four
  
  diff -r ... 4of
  --- /dev/null
  +++ b/4of
  @@ -0,0 +1,1 @@
  +4 t
  3: b9f922d0da40 Four - test
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qref -u
  # HG changeset patch
  # User jane
  # Parent 
  Four
  
  diff -r ... 4of
  --- /dev/null
  +++ b/4of
  @@ -0,0 +1,1 @@
  +4 t
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew with HG header
  popping 5.patch
  now at: 4.patch
  now at: 5.patch
  # HG changeset patch
  # User johndoe
  4: 72bc4a0467ef imported patch 5.patch - johndoe
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref
  adding 5
  # HG changeset patch
  # User johndoe
  # Parent 
  
  diff -r ... 5
  --- /dev/null
  +++ b/5
  @@ -0,0 +1,1 @@
  +5
  4: ff5c06112e5a [mq]: 5.patch - johndoe
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -U
  # HG changeset patch
  # User test
  # Parent 
  
  diff -r ... 5
  --- /dev/null
  +++ b/5
  @@ -0,0 +1,1 @@
  +5
  4: c947416c22b1 [mq]: 5.patch - test
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -u
  # HG changeset patch
  # User johndeere
  # Parent 
  
  diff -r ... 5
  --- /dev/null
  +++ b/5
  @@ -0,0 +1,1 @@
  +5
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qnew with plain header
  popping 6.patch
  now at: 5.patch
  now at: 6.patch
  From: test
  
  5: 7825a18ec839 imported patch 6.patch - test
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref
  adding 6
  From: test
  
  diff -r ... 6
  --- /dev/null
  +++ b/6
  @@ -0,0 +1,1 @@
  +6
  5: 09d19592680d [mq]: 6.patch - test
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -U
  From: test
  
  diff -r ... 6
  --- /dev/null
  +++ b/6
  @@ -0,0 +1,1 @@
  +6
  5: 09d19592680d [mq]: 6.patch - test
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== hg qref -u
  From: johndeere
  
  diff -r ... 6
  --- /dev/null
  +++ b/6
  @@ -0,0 +1,1 @@
  +6
  5: 32641ee07196 [mq]: 6.patch - johndeere
  4: 1d898e201a22 [mq]: 5.patch - johndeere
  3: 0dfb3111e7ee Four - jane
  2: a6686ee84fc3 Three (again) - maria
  1: a425cde5f493 [mq]: 2.patch - jane
  0: 3682f830e656 [mq]: 1.patch - mary
  ==== qpop -a / qpush -a
  popping 6.patch
  popping 5.patch
  popping 4.patch
  popping 3.patch
  popping 2.patch
  popping 1.patch
  patch queue now empty
  applying 1.patch
  applying 2.patch
  applying 3.patch
  applying 4.patch
  applying 5.patch
  applying 6.patch
  now at: 6.patch
  5: 1fb083c80457 imported patch 6.patch - johndeere
  4: 7e96e969691d imported patch 5.patch - johndeere
  3: c7147533d3cd Four - jane
  2: b383d04401ea Three (again) - maria
  1: fac2da4efc3c imported patch 2.patch - jane
  0: b6e237e8771b imported patch 1.patch - mary

  $ cd ..