tests/test-profile.t

simplemerge: stop merging file flags

As 384df4db6520 (merge: merge file flags together with file content,
2013-01-09) explains, we shouldn't do a 3-way merge of the
symlink. However, since 84614212ae39 (flags: actually merge flags in
simplemerge, 2020-05-16), we do that in
`simplemerge.simplemerge()`. What's more, the merging of the
executable flag there isn't actually necessary; it was made a no-op by
the very next commit, i.e. 4234c9af515d (flags: read flag from
dirstate/disk for workingcopyctx (issue5743), 2020-05-16).

I found the overall flag-merging code (not the bit in
`simplemerge.py`) very hard to follow, but I think I now finally
understand how it works. `mergestate.resolve()` calculates the merged
file flags and sets them on the local side of the merge (confusingly
by calling `_restore_backup()`). Then it calls
`filemerge.filemerge()`, which in turn calls
`simplemerge.simplemerge()` (if premerge is enabled). That means that
the flags on the local side `fcs.flags()` are already correct when the
flag-merging code in `simplemerge.simplemerge()` runs. Interestingly,
that code still works when the local side already has the merged
value, it just doesn't change the value. Here's a truth table to
explain why:

```
BLOMCAR
0000000
0011111
0101011
0111111
1000000
1010000
1100000
1111101
```

B: Base
L: Local
O: Other
M: Merged flags from `mergestate.resolve()`, i.e. what's called "local"
   when we get to `simplemerge.simplemerge()`
C: `commonflags` in `simplemerge.simplemerge()`, i.e. `M & O`
A: `addedflags` in `simplemerge.simplemerge()`, i.e. `(M ^ O) - B`
R: Re-merged flags `simplemerge.simplemerge()`, i.e. `C | A`

As you can see, the re-merged flags are always unchanged compared to
the initial merged flags (R equals M).

Therefore, this patch effectively backs out 84614212ae39. (I might
later refactor this code to have the flags explicitly passed in.)

`simplemerge.simplemerge()` is also called from
`contrib/simplemerge.py`, but that code never passes any flags.

Differential Revision: https://phab.mercurial-scm.org/D11879

test --time

  $ hg --time help -q help 2>&1 | grep time > /dev/null
  $ hg init a
  $ cd a

Function to check that statprof ran
  $ statprofran () {
  >   egrep 'Sample count:|No samples recorded' > /dev/null
  > }

test --profile

  $ hg st --profile 2>&1 | statprofran

Abreviated version

  $ hg st --prof 2>&1 | statprofran

In alias

  $ hg --config "alias.profst=status --profile" profst 2>&1 | statprofran

#if lsprof

  $ prof () {
  >   hg --config profiling.type=ls --profile $@
  > }

  $ prof st 2>../out
  $ grep CallCount ../out > /dev/null || cat ../out

  $ prof --config profiling.output=../out st
  $ grep CallCount ../out > /dev/null || cat ../out

  $ prof --config profiling.output=blackbox --config extensions.blackbox= st
  $ grep CallCount .hg/blackbox.log > /dev/null || cat .hg/blackbox.log

  $ prof --config profiling.format=text st 2>../out
  $ grep CallCount ../out > /dev/null || cat ../out

  $ echo "[profiling]" >> $HGRCPATH
  $ echo "format=kcachegrind" >> $HGRCPATH

  $ prof st 2>../out
  $ grep 'events: Ticks' ../out > /dev/null || cat ../out

  $ prof --config profiling.output=../out st
  $ grep 'events: Ticks' ../out > /dev/null || cat ../out

#endif

#if lsprof serve

Profiling of HTTP requests works

  $ prof --config profiling.format=text --config profiling.output=../profile.log serve -d -p $HGPORT --pid-file ../hg.pid -A ../access.log
  $ cat ../hg.pid >> $DAEMON_PIDS
  $ hg -q clone -U http://localhost:$HGPORT ../clone

A single profile is logged because file logging doesn't append
  $ grep CallCount ../profile.log | wc -l
  \s*1 (re)

#endif

Install an extension that can sleep and guarantee a profiler has time to run

  $ cat >> sleepext_with_a_long_filename.py << EOF
  > import time
  > from mercurial import registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'sleep', [], b'hg sleep')
  > def sleep_for_at_least_one_stat_cycle(ui, *args, **kwargs):
  >     t = time.time()  # don't use time.sleep because we need CPU time
  >     while time.time() - t < 0.5:
  >         pass
  > EOF

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > sleep = `pwd`/sleepext_with_a_long_filename.py
  > EOF

statistical profiler works

  $ hg --profile sleep 2>../out
  $ cat ../out | statprofran

Various statprof formatters work

  $ hg --profile --config profiling.statformat=byline sleep 2>../out || cat ../out
  $ grep -v _path_stat ../out | head -n 3
    %   cumulative      self          
   time    seconds   seconds  name    
  * sleepext_with_a_long_filename.py:*:sleep_for_at_least_one_stat_cycle (glob)
  $ cat ../out | statprofran

  $ hg --profile --config profiling.statformat=bymethod sleep 2>../out || cat ../out
  $ head -n 1 ../out
    %   cumulative      self          
  $ cat ../out | statprofran

Windows real time tracking is broken, only use CPU

#if no-windows
  $ hg --profile --config profiling.time-track=real --config profiling.statformat=hotpath sleep 2>../out || cat ../out
  $ cat ../out | statprofran
  $ grep sleepext_with_a_long_filename.py ../out | head -n 1
  .* [0-9.]+%  [0-9.]+s  sleepext_with_a_long_filename.py:\s*sleep_for_at_least_one_stat_cycle, line \d+:\s+(while|pass).* (re)
#endif

  $ hg --profile --config profiling.time-track=cpu --config profiling.statformat=hotpath sleep 2>../out || cat ../out
  $ cat ../out | statprofran
  $ grep sleepext_with_a_long_filename.py ../out | head -n 1
  .* [0-9.]+%  [0-9.]+s  sleepext_with_a_long_filename.py:\s*sleep_for_at_least_one_stat_cycle, line \d+:\s+(while|pass).* (re)

  $ hg --profile --config profiling.statformat=json sleep 2>../out || cat ../out
  $ cat ../out
  \[\[-?\d+.* (re)

statprof can be used as a standalone module

  $ "$PYTHON" -m mercurial.statprof hotpath
  must specify --file to load
  [1]

  $ cd ..

#if no-chg
profiler extension could be loaded before other extensions

  $ cat > fooprof.py <<EOF
  > from __future__ import absolute_import
  > import contextlib
  > import sys
  > @contextlib.contextmanager
  > def profile(ui, fp):
  >     print('fooprof: start profile')
  >     sys.stdout.flush()
  >     yield
  >     print('fooprof: end profile')
  >     sys.stdout.flush()
  > def extsetup(ui):
  >     ui.write(b'fooprof: loaded\n')
  > EOF

  $ cat > otherextension.py <<EOF
  > from __future__ import absolute_import
  > def extsetup(ui):
  >     ui.write(b'otherextension: loaded\n')
  > EOF

  $ hg init b
  $ cd b
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > other = $TESTTMP/otherextension.py
  > fooprof = $TESTTMP/fooprof.py
  > EOF

  $ hg root
  otherextension: loaded
  fooprof: loaded
  $TESTTMP/b
  $ HGPROF=fooprof hg root --profile
  fooprof: loaded
  fooprof: start profile
  otherextension: loaded
  $TESTTMP/b
  fooprof: end profile

  $ HGPROF=other hg root --profile 2>&1 | head -n 2
  otherextension: loaded
  unrecognized profiler 'other' - ignored

  $ HGPROF=unknown hg root --profile 2>&1 | head -n 1
  unrecognized profiler 'unknown' - ignored

  $ cd ..
#endif