bpo-40495: compileall option to hardlink duplicate pyc files (GH-19901)

compileall is now able to use hardlinks to prevent duplicates in a
case when .pyc files for different optimization levels have the same content.

Co-authored-by: Miro Hrončok <miro@hroncok.cz>
Co-authored-by: Victor Stinner <vstinner@python.org>
This commit is contained in:
Lumír 'Frenzy' Balhar 2020-05-14 16:17:22 +02:00 committed by GitHub
parent 7443d42021
commit e77d428856
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6 changed files with 285 additions and 15 deletions

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@ -113,6 +113,11 @@ compile Python sources.
Ignore symlinks pointing outside the given directory.
.. cmdoption:: --hardlink-dupes
If two ``.pyc`` files with different optimization level have
the same content, use hard links to consolidate duplicate files.
.. versionchanged:: 3.2
Added the ``-i``, ``-b`` and ``-h`` options.
@ -125,7 +130,7 @@ compile Python sources.
Added the ``--invalidation-mode`` option.
.. versionchanged:: 3.9
Added the ``-s``, ``-p``, ``-e`` options.
Added the ``-s``, ``-p``, ``-e`` and ``--hardlink-dupes`` options.
Raised the default recursion limit from 10 to
:py:func:`sys.getrecursionlimit()`.
Added the possibility to specify the ``-o`` option multiple times.
@ -143,7 +148,7 @@ runtime.
Public functions
----------------
.. function:: compile_dir(dir, maxlevels=sys.getrecursionlimit(), ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, workers=1, invalidation_mode=None, \*, stripdir=None, prependdir=None, limit_sl_dest=None)
.. function:: compile_dir(dir, maxlevels=sys.getrecursionlimit(), ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, workers=1, invalidation_mode=None, \*, stripdir=None, prependdir=None, limit_sl_dest=None, hardlink_dupes=False)
Recursively descend the directory tree named by *dir*, compiling all :file:`.py`
files along the way. Return a true value if all the files compiled successfully,
@ -193,6 +198,9 @@ Public functions
the ``-s``, ``-p`` and ``-e`` options described above.
They may be specified as ``str``, ``bytes`` or :py:class:`os.PathLike`.
If *hardlink_dupes* is true and two ``.pyc`` files with different optimization
level have the same content, use hard links to consolidate duplicate files.
.. versionchanged:: 3.2
Added the *legacy* and *optimize* parameter.
@ -219,9 +227,9 @@ Public functions
Setting *workers* to 0 now chooses the optimal number of cores.
.. versionchanged:: 3.9
Added *stripdir*, *prependdir* and *limit_sl_dest* arguments.
Added *stripdir*, *prependdir*, *limit_sl_dest* and *hardlink_dupes* arguments.
.. function:: compile_file(fullname, ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, invalidation_mode=None, \*, stripdir=None, prependdir=None, limit_sl_dest=None)
.. function:: compile_file(fullname, ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, invalidation_mode=None, \*, stripdir=None, prependdir=None, limit_sl_dest=None, hardlink_dupes=False)
Compile the file with path *fullname*. Return a true value if the file
compiled successfully, and a false value otherwise.
@ -257,6 +265,9 @@ Public functions
the ``-s``, ``-p`` and ``-e`` options described above.
They may be specified as ``str``, ``bytes`` or :py:class:`os.PathLike`.
If *hardlink_dupes* is true and two ``.pyc`` files with different optimization
level have the same content, use hard links to consolidate duplicate files.
.. versionadded:: 3.2
.. versionchanged:: 3.5
@ -273,7 +284,7 @@ Public functions
The *invalidation_mode* parameter's default value is updated to None.
.. versionchanged:: 3.9
Added *stripdir*, *prependdir* and *limit_sl_dest* arguments.
Added *stripdir*, *prependdir*, *limit_sl_dest* and *hardlink_dupes* arguments.
.. function:: compile_path(skip_curdir=True, maxlevels=0, force=False, quiet=0, legacy=False, optimize=-1, invalidation_mode=None)

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@ -245,6 +245,16 @@ that schedules a shutdown for the default executor that waits on the
Added :class:`asyncio.PidfdChildWatcher`, a Linux-specific child watcher
implementation that polls process file descriptors. (:issue:`38692`)
compileall
----------
Added new possibility to use hardlinks for duplicated ``.pyc`` files: *hardlink_dupes* parameter and --hardlink-dupes command line option.
(Contributed by Lumír 'Frenzy' Balhar in :issue:`40495`.)
Added new options for path manipulation in resulting ``.pyc`` files: *stripdir*, *prependdir*, *limit_sl_dest* parameters and -s, -p, -e command line options.
Added the possibility to specify the option for an optimization level multiple times.
(Contributed by Lumír 'Frenzy' Balhar in :issue:`38112`.)
concurrent.futures
------------------

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@ -15,6 +15,7 @@ import sys
import importlib.util
import py_compile
import struct
import filecmp
from functools import partial
from pathlib import Path
@ -47,7 +48,7 @@ def _walk_dir(dir, maxlevels, quiet=0):
def compile_dir(dir, maxlevels=None, ddir=None, force=False,
rx=None, quiet=0, legacy=False, optimize=-1, workers=1,
invalidation_mode=None, *, stripdir=None,
prependdir=None, limit_sl_dest=None):
prependdir=None, limit_sl_dest=None, hardlink_dupes=False):
"""Byte-compile all modules in the given directory tree.
Arguments (only dir is required):
@ -70,6 +71,7 @@ def compile_dir(dir, maxlevels=None, ddir=None, force=False,
after stripdir
limit_sl_dest: ignore symlinks if they are pointing outside of
the defined path
hardlink_dupes: hardlink duplicated pyc files
"""
ProcessPoolExecutor = None
if ddir is not None and (stripdir is not None or prependdir is not None):
@ -104,7 +106,8 @@ def compile_dir(dir, maxlevels=None, ddir=None, force=False,
invalidation_mode=invalidation_mode,
stripdir=stripdir,
prependdir=prependdir,
limit_sl_dest=limit_sl_dest),
limit_sl_dest=limit_sl_dest,
hardlink_dupes=hardlink_dupes),
files)
success = min(results, default=True)
else:
@ -112,14 +115,15 @@ def compile_dir(dir, maxlevels=None, ddir=None, force=False,
if not compile_file(file, ddir, force, rx, quiet,
legacy, optimize, invalidation_mode,
stripdir=stripdir, prependdir=prependdir,
limit_sl_dest=limit_sl_dest):
limit_sl_dest=limit_sl_dest,
hardlink_dupes=hardlink_dupes):
success = False
return success
def compile_file(fullname, ddir=None, force=False, rx=None, quiet=0,
legacy=False, optimize=-1,
invalidation_mode=None, *, stripdir=None, prependdir=None,
limit_sl_dest=None):
limit_sl_dest=None, hardlink_dupes=False):
"""Byte-compile one file.
Arguments (only fullname is required):
@ -140,6 +144,7 @@ def compile_file(fullname, ddir=None, force=False, rx=None, quiet=0,
after stripdir
limit_sl_dest: ignore symlinks if they are pointing outside of
the defined path.
hardlink_dupes: hardlink duplicated pyc files
"""
if ddir is not None and (stripdir is not None or prependdir is not None):
@ -176,6 +181,14 @@ def compile_file(fullname, ddir=None, force=False, rx=None, quiet=0,
if isinstance(optimize, int):
optimize = [optimize]
# Use set() to remove duplicates.
# Use sorted() to create pyc files in a deterministic order.
optimize = sorted(set(optimize))
if hardlink_dupes and len(optimize) < 2:
raise ValueError("Hardlinking of duplicated bytecode makes sense "
"only for more than one optimization level")
if rx is not None:
mo = rx.search(fullname)
if mo:
@ -220,10 +233,16 @@ def compile_file(fullname, ddir=None, force=False, rx=None, quiet=0,
if not quiet:
print('Compiling {!r}...'.format(fullname))
try:
for opt_level, cfile in opt_cfiles.items():
for index, opt_level in enumerate(optimize):
cfile = opt_cfiles[opt_level]
ok = py_compile.compile(fullname, cfile, dfile, True,
optimize=opt_level,
invalidation_mode=invalidation_mode)
if index > 0 and hardlink_dupes:
previous_cfile = opt_cfiles[optimize[index - 1]]
if filecmp.cmp(cfile, previous_cfile, shallow=False):
os.unlink(cfile)
os.link(previous_cfile, cfile)
except py_compile.PyCompileError as err:
success = False
if quiet >= 2:
@ -352,6 +371,9 @@ def main():
'Python interpreter itself (specified by -O).'))
parser.add_argument('-e', metavar='DIR', dest='limit_sl_dest',
help='Ignore symlinks pointing outsite of the DIR')
parser.add_argument('--hardlink-dupes', action='store_true',
dest='hardlink_dupes',
help='Hardlink duplicated pyc files')
args = parser.parse_args()
compile_dests = args.compile_dest
@ -371,6 +393,10 @@ def main():
if args.opt_levels is None:
args.opt_levels = [-1]
if len(args.opt_levels) == 1 and args.hardlink_dupes:
parser.error(("Hardlinking of duplicated bytecode makes sense "
"only for more than one optimization level."))
if args.ddir is not None and (
args.stripdir is not None or args.prependdir is not None
):
@ -404,7 +430,8 @@ def main():
stripdir=args.stripdir,
prependdir=args.prependdir,
optimize=args.opt_levels,
limit_sl_dest=args.limit_sl_dest):
limit_sl_dest=args.limit_sl_dest,
hardlink_dupes=args.hardlink_dupes):
success = False
else:
if not compile_dir(dest, maxlevels, args.ddir,
@ -414,7 +441,8 @@ def main():
stripdir=args.stripdir,
prependdir=args.prependdir,
optimize=args.opt_levels,
limit_sl_dest=args.limit_sl_dest):
limit_sl_dest=args.limit_sl_dest,
hardlink_dupes=args.hardlink_dupes):
success = False
return success
else:

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@ -1,16 +1,19 @@
import sys
import compileall
import contextlib
import filecmp
import importlib.util
import test.test_importlib.util
import io
import itertools
import os
import pathlib
import py_compile
import shutil
import struct
import sys
import tempfile
import test.test_importlib.util
import time
import unittest
import io
from unittest import mock, skipUnless
try:
@ -26,6 +29,24 @@ from .test_py_compile import without_source_date_epoch
from .test_py_compile import SourceDateEpochTestMeta
def get_pyc(script, opt):
if not opt:
# Replace None and 0 with ''
opt = ''
return importlib.util.cache_from_source(script, optimization=opt)
def get_pycs(script):
return [get_pyc(script, opt) for opt in (0, 1, 2)]
def is_hardlink(filename1, filename2):
"""Returns True if two files have the same inode (hardlink)"""
inode1 = os.stat(filename1).st_ino
inode2 = os.stat(filename2).st_ino
return inode1 == inode2
class CompileallTestsBase:
def setUp(self):
@ -825,6 +846,32 @@ class CommandLineTestsBase:
self.assertTrue(os.path.isfile(allowed_bc))
self.assertFalse(os.path.isfile(prohibited_bc))
def test_hardlink_bad_args(self):
# Bad arguments combination, hardlink deduplication make sense
# only for more than one optimization level
self.assertRunNotOK(self.directory, "-o 1", "--hardlink-dupes")
def test_hardlink(self):
# 'a = 0' code produces the same bytecode for the 3 optimization
# levels. All three .pyc files must have the same inode (hardlinks).
#
# If deduplication is disabled, all pyc files must have different
# inodes.
for dedup in (True, False):
with tempfile.TemporaryDirectory() as path:
with self.subTest(dedup=dedup):
script = script_helper.make_script(path, "script", "a = 0")
pycs = get_pycs(script)
args = ["-q", "-o 0", "-o 1", "-o 2"]
if dedup:
args.append("--hardlink-dupes")
self.assertRunOK(path, *args)
self.assertEqual(is_hardlink(pycs[0], pycs[1]), dedup)
self.assertEqual(is_hardlink(pycs[1], pycs[2]), dedup)
self.assertEqual(is_hardlink(pycs[0], pycs[2]), dedup)
class CommandLineTestsWithSourceEpoch(CommandLineTestsBase,
unittest.TestCase,
@ -841,5 +888,176 @@ class CommandLineTestsNoSourceEpoch(CommandLineTestsBase,
class HardlinkDedupTestsBase:
# Test hardlink_dupes parameter of compileall.compile_dir()
def setUp(self):
self.path = None
@contextlib.contextmanager
def temporary_directory(self):
with tempfile.TemporaryDirectory() as path:
self.path = path
yield path
self.path = None
def make_script(self, code, name="script"):
return script_helper.make_script(self.path, name, code)
def compile_dir(self, *, dedup=True, optimize=(0, 1, 2), force=False):
compileall.compile_dir(self.path, quiet=True, optimize=optimize,
hardlink_dupes=dedup, force=force)
def test_bad_args(self):
# Bad arguments combination, hardlink deduplication make sense
# only for more than one optimization level
with self.temporary_directory():
self.make_script("pass")
with self.assertRaises(ValueError):
compileall.compile_dir(self.path, quiet=True, optimize=0,
hardlink_dupes=True)
with self.assertRaises(ValueError):
# same optimization level specified twice:
# compile_dir() removes duplicates
compileall.compile_dir(self.path, quiet=True, optimize=[0, 0],
hardlink_dupes=True)
def create_code(self, docstring=False, assertion=False):
lines = []
if docstring:
lines.append("'module docstring'")
lines.append('x = 1')
if assertion:
lines.append("assert x == 1")
return '\n'.join(lines)
def iter_codes(self):
for docstring in (False, True):
for assertion in (False, True):
code = self.create_code(docstring=docstring, assertion=assertion)
yield (code, docstring, assertion)
def test_disabled(self):
# Deduplication disabled, no hardlinks
for code, docstring, assertion in self.iter_codes():
with self.subTest(docstring=docstring, assertion=assertion):
with self.temporary_directory():
script = self.make_script(code)
pycs = get_pycs(script)
self.compile_dir(dedup=False)
self.assertFalse(is_hardlink(pycs[0], pycs[1]))
self.assertFalse(is_hardlink(pycs[0], pycs[2]))
self.assertFalse(is_hardlink(pycs[1], pycs[2]))
def check_hardlinks(self, script, docstring=False, assertion=False):
pycs = get_pycs(script)
self.assertEqual(is_hardlink(pycs[0], pycs[1]),
not assertion)
self.assertEqual(is_hardlink(pycs[0], pycs[2]),
not assertion and not docstring)
self.assertEqual(is_hardlink(pycs[1], pycs[2]),
not docstring)
def test_hardlink(self):
# Test deduplication on all combinations
for code, docstring, assertion in self.iter_codes():
with self.subTest(docstring=docstring, assertion=assertion):
with self.temporary_directory():
script = self.make_script(code)
self.compile_dir()
self.check_hardlinks(script, docstring, assertion)
def test_only_two_levels(self):
# Don't build the 3 optimization levels, but only 2
for opts in ((0, 1), (1, 2), (0, 2)):
with self.subTest(opts=opts):
with self.temporary_directory():
# code with no dostring and no assertion:
# same bytecode for all optimization levels
script = self.make_script(self.create_code())
self.compile_dir(optimize=opts)
pyc1 = get_pyc(script, opts[0])
pyc2 = get_pyc(script, opts[1])
self.assertTrue(is_hardlink(pyc1, pyc2))
def test_duplicated_levels(self):
# compile_dir() must not fail if optimize contains duplicated
# optimization levels and/or if optimization levels are not sorted.
with self.temporary_directory():
# code with no dostring and no assertion:
# same bytecode for all optimization levels
script = self.make_script(self.create_code())
self.compile_dir(optimize=[1, 0, 1, 0])
pyc1 = get_pyc(script, 0)
pyc2 = get_pyc(script, 1)
self.assertTrue(is_hardlink(pyc1, pyc2))
def test_recompilation(self):
# Test compile_dir() when pyc files already exists and the script
# content changed
with self.temporary_directory():
script = self.make_script("a = 0")
self.compile_dir()
# All three levels have the same inode
self.check_hardlinks(script)
pycs = get_pycs(script)
inode = os.stat(pycs[0]).st_ino
# Change of the module content
script = self.make_script("print(0)")
# Recompilation without -o 1
self.compile_dir(optimize=[0, 2], force=True)
# opt-1.pyc should have the same inode as before and others should not
self.assertEqual(inode, os.stat(pycs[1]).st_ino)
self.assertTrue(is_hardlink(pycs[0], pycs[2]))
self.assertNotEqual(inode, os.stat(pycs[2]).st_ino)
# opt-1.pyc and opt-2.pyc have different content
self.assertFalse(filecmp.cmp(pycs[1], pycs[2], shallow=True))
def test_import(self):
# Test that import updates a single pyc file when pyc files already
# exists and the script content changed
with self.temporary_directory():
script = self.make_script(self.create_code(), name="module")
self.compile_dir()
# All three levels have the same inode
self.check_hardlinks(script)
pycs = get_pycs(script)
inode = os.stat(pycs[0]).st_ino
# Change of the module content
script = self.make_script("print(0)", name="module")
# Import the module in Python with -O (optimization level 1)
script_helper.assert_python_ok(
"-O", "-c", "import module", __isolated=False, PYTHONPATH=self.path
)
# Only opt-1.pyc is changed
self.assertEqual(inode, os.stat(pycs[0]).st_ino)
self.assertEqual(inode, os.stat(pycs[2]).st_ino)
self.assertFalse(is_hardlink(pycs[1], pycs[2]))
# opt-1.pyc and opt-2.pyc have different content
self.assertFalse(filecmp.cmp(pycs[1], pycs[2], shallow=True))
class HardlinkDedupTestsWithSourceEpoch(HardlinkDedupTestsBase,
unittest.TestCase,
metaclass=SourceDateEpochTestMeta,
source_date_epoch=True):
pass
class HardlinkDedupTestsNoSourceEpoch(HardlinkDedupTestsBase,
unittest.TestCase,
metaclass=SourceDateEpochTestMeta,
source_date_epoch=False):
pass
if __name__ == "__main__":
unittest.main()

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@ -86,6 +86,7 @@ Marcin Bachry
Alfonso Baciero
Dwayne Bailey
Stig Bakken
Lumír Balhar
Aleksandr Balezin
Greg Ball
Lewis Ball

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@ -0,0 +1,2 @@
:mod:`compileall` is now able to use hardlinks to prevent duplicates in a
case when ``.pyc`` files for different optimization levels have the same content.