view tests/test-narrow-patterns.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

  $ . "$TESTDIR/narrow-library.sh"

initialize nested directories to validate complex include/exclude patterns

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF

  $ echo root > root
  $ hg add root
  $ hg commit -m 'add root'

  $ for d in dir1 dir2 dir1/dirA dir1/dirB dir2/dirA dir2/dirB
  > do
  >   mkdir -p $d
  >   echo $d/foo > $d/foo
  >   hg add $d/foo
  >   hg commit -m "add $d/foo"
  >   echo $d/bar > $d/bar
  >   hg add $d/bar
  >   hg commit -m "add $d/bar"
  > done
#if execbit
  $ chmod +x dir1/dirA/foo
  $ hg commit -m "make dir1/dirA/foo executable"
#else
  $ hg import --bypass - <<EOF
  > # HG changeset patch
  > make dir1/dirA/foo executable
  > 
  > diff --git a/dir1/dirA/foo b/dir1/dirA/foo
  > old mode 100644
  > new mode 100755
  > EOF
  applying patch from stdin
  $ hg update -qr tip
#endif
  $ hg log -G -T '{rev} {node|short} {files}\n'
  @  13 c87ca422d521 dir1/dirA/foo
  |
  o  12 951b8a83924e dir2/dirB/bar
  |
  o  11 01ae5a51b563 dir2/dirB/foo
  |
  o  10 5eababdf0ac5 dir2/dirA/bar
  |
  o  9 99d690663739 dir2/dirA/foo
  |
  o  8 8e80155d5445 dir1/dirB/bar
  |
  o  7 406760310428 dir1/dirB/foo
  |
  o  6 623466a5f475 dir1/dirA/bar
  |
  o  5 06ff3a5be997 dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da root
  
  $ cd ..

clone a narrow portion of the master, such that we can widen it later

  $ hg clone --narrow ssh://user@dummy/master narrow \
  > --include dir1 \
  > --include dir2 \
  > --exclude dir1/dirA \
  > --exclude dir1/dirB \
  > --exclude dir2/dirA \
  > --exclude dir2/dirB
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 6 changesets with 4 changes to 4 files
  new changesets *:* (glob)
  updating to branch default
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd narrow
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirA
  X path:dir1/dirB
  X path:dir2/dirA
  X path:dir2/dirB
  $ hg manifest -r tip
  dir1/bar
  dir1/dirA/bar
  dir1/dirA/foo
  dir1/dirB/bar
  dir1/dirB/foo
  dir1/foo
  dir2/bar
  dir2/dirA/bar
  dir2/dirA/foo
  dir2/dirB/bar
  dir2/dirB/foo
  dir2/foo
  root
  $ find * | sort
  dir1
  dir1/bar
  dir1/foo
  dir2
  dir2/bar
  dir2/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  5 c87ca422d521... dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

widen the narrow checkout

  $ hg tracked --removeexclude dir1/dirA
  comparing with ssh://user@dummy/master
  searching for changes
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 6 changes to 6 files
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirB
  X path:dir2/dirA
  X path:dir2/dirB
  $ find * | sort
  dir1
  dir1/bar
  dir1/dirA
  dir1/dirA/bar
  dir1/dirA/foo
  dir1/foo
  dir2
  dir2/bar
  dir2/foo

#if execbit
  $ test -x dir1/dirA/foo && echo executable
  executable
  $ test -x dir1/dirA/bar || echo not executable
  not executable
#endif

  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  8 c87ca422d521 dir1/dirA/foo
  |
  o  7 951b8a83924e... dir2/dirB/bar
  |
  o  6 623466a5f475 dir1/dirA/bar
  |
  o  5 06ff3a5be997 dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

widen narrow spec again, but exclude a file in previously included spec

  $ hg tracked --removeexclude dir2/dirB --addexclude dir1/dirA/bar
  comparing with ssh://user@dummy/master
  searching for changes
  looking for local changes to affected paths
  deleting data/dir1/dirA/bar.i (reporevlogstore !)
  deleting data/dir1/dirA/bar/0eca1d0cbdaea4651d1d04d71976a6d2d9bfaae5 (reposimplestore !)
  deleting data/dir1/dirA/bar/index (reposimplestore !)
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 11 changesets with 7 changes to 7 files
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirA/bar
  X path:dir1/dirB
  X path:dir2/dirA
  $ find * | sort
  dir1
  dir1/bar
  dir1/dirA
  dir1/dirA/foo
  dir1/foo
  dir2
  dir2/bar
  dir2/dirB
  dir2/dirB/bar
  dir2/dirB/foo
  dir2/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  10 c87ca422d521 dir1/dirA/foo
  |
  o  9 951b8a83924e dir2/dirB/bar
  |
  o  8 01ae5a51b563 dir2/dirB/foo
  |
  o  7 5eababdf0ac5... dir2/dirA/bar
  |
  o  6 623466a5f475... dir1/dirA/bar
  |
  o  5 06ff3a5be997 dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

widen narrow spec yet again, excluding a directory in previous spec

  $ hg tracked --removeexclude dir2/dirA --addexclude dir1/dirA
  comparing with ssh://user@dummy/master
  searching for changes
  looking for local changes to affected paths
  deleting data/dir1/dirA/foo.i (reporevlogstore !)
  deleting data/dir1/dirA/foo/162caeb3d55dceb1fee793aa631ac8c73fcb8b5e (reposimplestore !)
  deleting data/dir1/dirA/foo/index (reposimplestore !)
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 13 changesets with 8 changes to 8 files
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirA
  X path:dir1/dirA/bar
  X path:dir1/dirB
  $ find * | sort
  dir1
  dir1/bar
  dir1/foo
  dir2
  dir2/bar
  dir2/dirA
  dir2/dirA/bar
  dir2/dirA/foo
  dir2/dirB
  dir2/dirB/bar
  dir2/dirB/foo
  dir2/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  12 c87ca422d521... dir1/dirA/foo
  |
  o  11 951b8a83924e dir2/dirB/bar
  |
  o  10 01ae5a51b563 dir2/dirB/foo
  |
  o  9 5eababdf0ac5 dir2/dirA/bar
  |
  o  8 99d690663739 dir2/dirA/foo
  |
  o  7 8e80155d5445... dir1/dirB/bar
  |
  o  6 623466a5f475... dir1/dirA/bar
  |
  o  5 06ff3a5be997... dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

include a directory that was previously explicitly excluded

  $ hg tracked --removeexclude dir1/dirA
  comparing with ssh://user@dummy/master
  searching for changes
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 13 changesets with 9 changes to 9 files
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirA/bar
  X path:dir1/dirB
  $ find * | sort
  dir1
  dir1/bar
  dir1/dirA
  dir1/dirA/foo
  dir1/foo
  dir2
  dir2/bar
  dir2/dirA
  dir2/dirA/bar
  dir2/dirA/foo
  dir2/dirB
  dir2/dirB/bar
  dir2/dirB/foo
  dir2/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  12 c87ca422d521 dir1/dirA/foo
  |
  o  11 951b8a83924e dir2/dirB/bar
  |
  o  10 01ae5a51b563 dir2/dirB/foo
  |
  o  9 5eababdf0ac5 dir2/dirA/bar
  |
  o  8 99d690663739 dir2/dirA/foo
  |
  o  7 8e80155d5445... dir1/dirB/bar
  |
  o  6 623466a5f475... dir1/dirA/bar
  |
  o  5 06ff3a5be997 dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

  $ cd ..

clone a narrow portion of the master, such that we can widen it later

  $ hg clone --narrow ssh://user@dummy/master narrow2 --include dir1/dirA
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 2 changes to 2 files
  new changesets *:* (glob)
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow2
  $ find * | sort
  dir1
  dir1/dirA
  dir1/dirA/bar
  dir1/dirA/foo
  $ hg tracked --addinclude dir1
  comparing with ssh://user@dummy/master
  searching for changes
  saved backup bundle to $TESTTMP/narrow2/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 10 changesets with 6 changes to 6 files
  $ find * | sort
  dir1
  dir1/bar
  dir1/dirA
  dir1/dirA/bar
  dir1/dirA/foo
  dir1/dirB
  dir1/dirB/bar
  dir1/dirB/foo
  dir1/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  9 c87ca422d521 dir1/dirA/foo
  |
  o  8 951b8a83924e... dir2/dirB/bar
  |
  o  7 8e80155d5445 dir1/dirB/bar
  |
  o  6 406760310428 dir1/dirB/foo
  |
  o  5 623466a5f475 dir1/dirA/bar
  |
  o  4 06ff3a5be997 dir1/dirA/foo
  |
  o  3 33227af02764... dir2/bar
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

Illegal patterns are rejected

  $ hg tracked --addinclude glob:**
  abort: invalid prefix on narrow pattern: glob:**
  (narrow patterns must begin with one of the following: path:, rootfilesin:)
  [255]

  $ hg tracked --addexclude set:ignored
  abort: invalid prefix on narrow pattern: set:ignored
  (narrow patterns must begin with one of the following: path:, rootfilesin:)
  [255]

  $ cat .hg/store/narrowspec
  [include]
  path:dir1
  path:dir1/dirA
  [exclude]

  $ cat > .hg/store/narrowspec << EOF
  > [include]
  > glob:**
  > EOF

  $ hg tracked
  abort: invalid prefix on narrow pattern: glob:**
  (narrow patterns must begin with one of the following: path:, rootfilesin:)
  [255]

  $ cat > .hg/store/narrowspec << EOF
  > [include]
  > path:.
  > [exclude]
  > set:ignored
  > EOF

  $ hg tracked
  abort: invalid prefix on narrow pattern: set:ignored
  (narrow patterns must begin with one of the following: path:, rootfilesin:)
  [255]