view tests/test-progress.t @ 44118:f81c17ec303c

hgdemandimport: apply lazy module loading to sys.meta_path finders

Python's `sys.meta_path` finders are the primary objects whose job it
is to find a module at import time. When `import` is called, Python
iterates objects in this list and calls `o.find_spec(...)` to find
a `ModuleSpec` (or None if the module couldn't be found by that
finder). If no meta path finder can find a module, import fails.

One of the default meta path finders is `PathFinder`. Its job is to
import modules from the filesystem and is probably the most important
importer. This finder looks at `sys.path` and `sys.path_hooks` to do
its job.

The `ModuleSpec` returned by `MetaPathImporter.find_spec()` has a
`loader` attribute, which defines the concrete module loader to use.
`sys.path_hooks` is a hook point for teaching `PathFinder` to
instantiate custom loader types.

Previously, we injected a custom `sys.path_hook` that told `PathFinder`
to wrap the default loaders with a loader that creates a module object
that is lazy.

This approach worked. But its main limitation was that it only applied
to the `PathFinder` meta path importer. There are other meta path
importers that are registered. And in the case of PyOxidizer loading
modules from memory, `PathFinder` doesn't come into play since
PyOxidizer's own meta path importer was handling all imports.

This commit changes our approach to lazy module loading by proxying
all meta path importers. Specifically, we overload the `find_spec()`
method to swap in a wrapped loader on the `ModuleSpec` before it
is returned. The end result of this is all meta path importers should
be lazy.

As much as I would have loved to utilize .__class__ manipulation to
achieve this, some meta path importers are implemented in C/Rust
in such a way that they cannot be monkeypatched. This is why we
use __getattribute__ to define a proxy.

Also, this change could theoretically open us up to regressions in
meta path importers whose loader is creating module objects which
can't be monkeypatched. But I'm not aware of any of these in the
wild. So I think we'll be safe.

According to hyperfine, this change yields a decent startup time win of
5-6ms:

```
Benchmark #1: ~/.pyenv/versions/3.6.10/bin/python ./hg version
  Time (mean ± σ):      86.8 ms ±   0.5 ms    [User: 78.0 ms, System: 8.7 ms]
  Range (min … max):    86.0 ms …  89.1 ms    50 runs

  Time (mean ± σ):      81.1 ms ±   2.7 ms    [User: 74.5 ms, System: 6.5 ms]
  Range (min … max):    77.8 ms …  90.5 ms    50 runs

Benchmark #2: ~/.pyenv/versions/3.7.6/bin/python ./hg version
  Time (mean ± σ):      78.9 ms ±   0.6 ms    [User: 70.2 ms, System: 8.7 ms]
  Range (min … max):    78.1 ms …  81.2 ms    50 runs

  Time (mean ± σ):      73.4 ms ±   0.6 ms    [User: 65.3 ms, System: 8.0 ms]
  Range (min … max):    72.4 ms …  75.7 ms    50 runs

Benchmark #3: ~/.pyenv/versions/3.8.1/bin/python ./hg version
  Time (mean ± σ):      78.1 ms ±   0.6 ms    [User: 70.2 ms, System: 7.9 ms]
  Range (min … max):    77.4 ms …  80.9 ms    50 runs

  Time (mean ± σ):      72.1 ms ±   0.4 ms    [User: 64.4 ms, System: 7.6 ms]
  Range (min … max):    71.4 ms …  74.1 ms    50 runs
```

Differential Revision: https://phab.mercurial-scm.org/D7954

  $ cat > loop.py <<EOF
  > from __future__ import absolute_import
  > import time
  > from mercurial import commands, registrar
  > 
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > 
  > class incrementingtime(object):
  >     def __init__(self):
  >         self._time = 0.0
  >     def __call__(self):
  >         self._time += 0.25
  >         return self._time
  > time.time = incrementingtime()
  > 
  > @command(b'loop',
  >     [(b'', b'total', b'', b'override for total'),
  >     (b'', b'nested', False, b'show nested results'),
  >     (b'', b'parallel', False, b'show parallel sets of results')],
  >     b'hg loop LOOPS',
  >     norepo=True)
  > def loop(ui, loops, **opts):
  >     loops = int(loops)
  >     total = None
  >     if loops >= 0:
  >         total = loops
  >     if opts.get('total', None):
  >         total = int(opts.get('total'))
  >     nested = False
  >     if opts.get('nested', None):
  >         nested = True
  >     loops = abs(loops)
  > 
  >     progress = ui.makeprogress(topiclabel, unit=b'loopnum', total=total)
  >     other = ui.makeprogress(b'other', unit=b'othernum', total=total)
  >     for i in range(loops):
  >         progress.update(i, item=getloopitem(i))
  >         if opts.get('parallel'):
  >             other.update(i, item=b'other.%d' % i)
  >         if nested:
  >             nested_steps = 2
  >             if i and i % 4 == 0:
  >                 nested_steps = 5
  >             nested = ui.makeprogress(b'nested', unit=b'nestnum',
  >                                      total=nested_steps)
  >             for j in range(nested_steps):
  >                 nested.update(j, item=b'nested.%d' % j)
  >             nested.complete()
  >     progress.complete()
  > 
  > topiclabel = b'loop'
  > def getloopitem(i):
  >     return b'loop.%d' % i
  > 
  > EOF

  $ cp $HGRCPATH $HGRCPATH.orig
  $ echo "[extensions]" >> $HGRCPATH
  $ echo "progress=" >> $HGRCPATH
  $ echo "loop=`pwd`/loop.py" >> $HGRCPATH
  $ echo "[progress]" >> $HGRCPATH
  $ echo "format = topic bar number" >> $HGRCPATH
  $ echo "assume-tty=1" >> $HGRCPATH
  $ echo "width=60" >> $HGRCPATH

test default params, display nothing because of delay

  $ hg -y loop 3
  $ echo "delay=0" >> $HGRCPATH
  $ echo "refresh=0" >> $HGRCPATH

test with delay=0, refresh=0

  $ hg -y loop 3
  \r (no-eol) (esc)
  loop [                                                ] 0/3\r (no-eol) (esc)
  loop [===============>                                ] 1/3\r (no-eol) (esc)
  loop [===============================>                ] 2/3\r (no-eol) (esc)
                                                              \r (no-eol) (esc)
no progress with --quiet
  $ hg -y loop 3 --quiet

test plain mode exception
  $ HGPLAINEXCEPT=progress hg -y loop 1
  \r (no-eol) (esc)
  loop [                                                ] 0/1\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

test nested short-lived topics (which shouldn't display with nestdelay):

  $ hg -y loop 3 --nested
  \r (no-eol) (esc)
  loop [                                                ] 0/3\r (no-eol) (esc)
  loop [===============>                                ] 1/3\r (no-eol) (esc)
  loop [===============================>                ] 2/3\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

Test nested long-lived topic which has the same name as a short-lived
peer. We shouldn't get stuck showing the short-lived inner steps, and
should go back to skipping the inner steps when the slow nested step
finishes.

  $ hg -y loop 7 --nested
  \r (no-eol) (esc)
  loop [                                                ] 0/7\r (no-eol) (esc)
  loop [=====>                                          ] 1/7\r (no-eol) (esc)
  loop [============>                                   ] 2/7\r (no-eol) (esc)
  loop [===================>                            ] 3/7\r (no-eol) (esc)
  loop [==========================>                     ] 4/7\r (no-eol) (esc)
  nested [==========================>                   ] 3/5\r (no-eol) (esc)
  nested [===================================>          ] 4/5\r (no-eol) (esc)
  loop [=================================>              ] 5/7\r (no-eol) (esc)
  loop [========================================>       ] 6/7\r (no-eol) (esc)
                                                              \r (no-eol) (esc)


  $ hg --config progress.changedelay=0 -y loop 3 --nested
  \r (no-eol) (esc)
  loop [                                                ] 0/3\r (no-eol) (esc)
  nested [                                              ] 0/2\r (no-eol) (esc)
  nested [======================>                       ] 1/2\r (no-eol) (esc)
  loop [===============>                                ] 1/3\r (no-eol) (esc)
  nested [                                              ] 0/2\r (no-eol) (esc)
  nested [======================>                       ] 1/2\r (no-eol) (esc)
  loop [===============================>                ] 2/3\r (no-eol) (esc)
  nested [                                              ] 0/2\r (no-eol) (esc)
  nested [======================>                       ] 1/2\r (no-eol) (esc)
                                                              \r (no-eol) (esc)


test two topics being printed in parallel (as when we're doing a local
--pull clone, where you get the unbundle and bundle progress at the
same time):
  $ hg loop 3 --parallel
  \r (no-eol) (esc)
  loop [                                                ] 0/3\r (no-eol) (esc)
  loop [===============>                                ] 1/3\r (no-eol) (esc)
  loop [===============================>                ] 2/3\r (no-eol) (esc)
                                                              \r (no-eol) (esc)
test refresh is taken in account

  $ hg -y --config progress.refresh=100 loop 3

test format options 1

  $ hg -y --config 'progress.format=number topic item+2' loop 2
  \r (no-eol) (esc)
  0/2 loop lo\r (no-eol) (esc)
  1/2 loop lo\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

test format options 2

  $ hg -y --config 'progress.format=number item-3 bar' loop 2
  \r (no-eol) (esc)
  0/2 p.0 [                                                 ]\r (no-eol) (esc)
  1/2 p.1 [=======================>                         ]\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

test format options and indeterminate progress

  $ hg -y --config 'progress.format=number item bar' loop -- -2
  \r (no-eol) (esc)
  0 loop.0               [ <=>                              ]\r (no-eol) (esc)
  1 loop.1               [  <=>                             ]\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

make sure things don't fall over if count > total

  $ hg -y loop --total 4 6
  \r (no-eol) (esc)
  loop [                                                ] 0/4\r (no-eol) (esc)
  loop [===========>                                    ] 1/4\r (no-eol) (esc)
  loop [=======================>                        ] 2/4\r (no-eol) (esc)
  loop [===================================>            ] 3/4\r (no-eol) (esc)
  loop [===============================================>] 4/4\r (no-eol) (esc)
  loop [ <=>                                            ] 5/4\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

test immediate progress completion

  $ hg -y loop 0

test delay time estimates

#if no-chg

  $ cp $HGRCPATH.orig $HGRCPATH
  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mocktime=$TESTDIR/mocktime.py" >> $HGRCPATH
  $ echo "progress=" >> $HGRCPATH
  $ echo "loop=`pwd`/loop.py" >> $HGRCPATH
  $ echo "[progress]" >> $HGRCPATH
  $ echo "assume-tty=1" >> $HGRCPATH
  $ echo "delay=25" >> $HGRCPATH
  $ echo "width=60" >> $HGRCPATH

  $ MOCKTIME=11 hg -y loop 8
  \r (no-eol) (esc)
  loop [=========>                                ] 2/8 1m07s\r (no-eol) (esc)
  loop [===============>                            ] 3/8 56s\r (no-eol) (esc)
  loop [=====================>                      ] 4/8 45s\r (no-eol) (esc)
  loop [==========================>                 ] 5/8 34s\r (no-eol) (esc)
  loop [================================>           ] 6/8 23s\r (no-eol) (esc)
  loop [=====================================>      ] 7/8 12s\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

  $ MOCKTIME=10000 hg -y loop 4
  \r (no-eol) (esc)
  loop [                                                ] 0/4\r (no-eol) (esc)
  loop [=========>                                ] 1/4 8h21m\r (no-eol) (esc)
  loop [====================>                     ] 2/4 5h34m\r (no-eol) (esc)
  loop [==============================>           ] 3/4 2h47m\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

  $ MOCKTIME=1000000 hg -y loop 4
  \r (no-eol) (esc)
  loop [                                                ] 0/4\r (no-eol) (esc)
  loop [=========>                                ] 1/4 5w00d\r (no-eol) (esc)
  loop [====================>                     ] 2/4 3w03d\r (no-eol) (esc)
  loop [=============================>           ] 3/4 11d14h\r (no-eol) (esc)
                                                              \r (no-eol) (esc)


  $ MOCKTIME=14000000 hg -y loop 4
  \r (no-eol) (esc)
  loop [                                                ] 0/4\r (no-eol) (esc)
  loop [=========>                                ] 1/4 1y18w\r (no-eol) (esc)
  loop [===================>                     ] 2/4 46w03d\r (no-eol) (esc)
  loop [=============================>           ] 3/4 23w02d\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

Non-linear progress:

  $ MOCKTIME='20 20 20 20 20 20 20 20 20 20 500 500 500 500 500 20 20 20 20 20' hg -y loop 20
  \r (no-eol) (esc)
  loop [=>                                      ]  1/20 6m21s\r (no-eol) (esc)
  loop [===>                                    ]  2/20 6m01s\r (no-eol) (esc)
  loop [=====>                                  ]  3/20 5m41s\r (no-eol) (esc)
  loop [=======>                                ]  4/20 5m21s\r (no-eol) (esc)
  loop [=========>                              ]  5/20 5m01s\r (no-eol) (esc)
  loop [===========>                            ]  6/20 4m41s\r (no-eol) (esc)
  loop [=============>                          ]  7/20 4m21s\r (no-eol) (esc)
  loop [===============>                        ]  8/20 4m01s\r (no-eol) (esc)
  loop [================>                      ]  9/20 25m40s\r (no-eol) (esc)
  loop [===================>                    ] 10/20 1h06m\r (no-eol) (esc)
  loop [=====================>                  ] 11/20 1h13m\r (no-eol) (esc)
  loop [=======================>                ] 12/20 1h07m\r (no-eol) (esc)
  loop [========================>              ] 13/20 58m19s\r (no-eol) (esc)
  loop [===========================>            ] 14/20 7m09s\r (no-eol) (esc)
  loop [=============================>          ] 15/20 3m38s\r (no-eol) (esc)
  loop [===============================>        ] 16/20 2m15s\r (no-eol) (esc)
  loop [=================================>      ] 17/20 1m27s\r (no-eol) (esc)
  loop [====================================>     ] 18/20 52s\r (no-eol) (esc)
  loop [======================================>   ] 19/20 25s\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

Time estimates should not fail when there's no end point:
  $ MOCKTIME=11 hg -y loop -- -4
  \r (no-eol) (esc)
  loop [ <=>                                              ] 2\r (no-eol) (esc)
  loop [  <=>                                             ] 3\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

#endif

test line trimming by '[progress] width', when progress topic contains
multi-byte characters, of which length of byte sequence and columns in
display are different from each other.

  $ cp $HGRCPATH.orig $HGRCPATH
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > progress=
  > loop=`pwd`/loop.py
  > [progress]
  > assume-tty = 1
  > delay = 0
  > refresh = 0
  > EOF

  $ rm -f loop.pyc
  $ cat >> loop.py <<EOF
  > # use non-ascii characters as topic label of progress
  > # 2 x 4 = 8 columns, but 3 x 4 = 12 bytes
  > topiclabel = u'\u3042\u3044\u3046\u3048'.encode('utf-8')
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [progress]
  > format = topic number
  > width= 12
  > EOF

  $ hg --encoding utf-8 -y loop --total 3 3
  \r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88 0/3\r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88 1/3\r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88 2/3\r (no-eol) (esc)
              \r (no-eol) (esc)

test calculation of bar width, when progress topic contains multi-byte
characters, of which length of byte sequence and columns in display
are different from each other.

  $ cat >> $HGRCPATH <<EOF
  > [progress]
  > format = topic bar
  > width= 21
  > # progwidth should be 9 (= 21 - (8+1) - 3)
  > EOF

  $ hg --encoding utf-8 -y loop --total 3 3
  \r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88 [         ]\r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88 [==>      ]\r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88 [=====>   ]\r (no-eol) (esc)
                       \r (no-eol) (esc)

test trimming progress items, when they contain multi-byte characters,
of which length of byte sequence and columns in display are different
from each other.

  $ rm -f loop.pyc
  $ rm -Rf __pycache__
  $ cat >> loop.py <<EOF
  > # use non-ascii characters as loop items of progress
  > loopitems = [
  >     u'\u3042\u3044'.encode('utf-8'), # 2 x 2 = 4 columns
  >     u'\u3042\u3044\u3046'.encode('utf-8'), # 2 x 3 = 6 columns
  >     u'\u3042\u3044\u3046\u3048'.encode('utf-8'), # 2 x 4 = 8 columns
  > ]
  > def getloopitem(i):
  >     return loopitems[i % len(loopitems)]
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [progress]
  > # trim at tail side
  > format = item+6
  > EOF

  $ hg --encoding utf-8 -y loop --total 3 3
  \r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84  \r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\r (no-eol) (esc)
                       \r (no-eol) (esc)

  $ cat >> $HGRCPATH <<EOF
  > [progress]
  > # trim at left side
  > format = item-6
  > EOF

  $ hg --encoding utf-8 -y loop --total 3 3
  \r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84  \r (no-eol) (esc)
  \xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\r (no-eol) (esc)
  \xe3\x81\x84\xe3\x81\x86\xe3\x81\x88\r (no-eol) (esc)
                       \r (no-eol) (esc)