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Merged
merged 3 commits into from
Apr 17, 2017
Merged

bpo-29514: Check magic number for bugfix release #54

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51835c7
bpo-29514: Check magic number for micro release
appeltel Feb 12, 2017
9ea7c52
Simplify magic number release test
appeltel Mar 11, 2017
1e32a1b
Improve magic number test execution and message
appeltel Mar 12, 2017
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15 changes: 0 additions & 15 deletions Lib/importlib/_bootstrap_external.py
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Original file line number Diff line number Diff line change
Expand Up @@ -248,21 +248,6 @@ def _write_atomic(path, data, mode=0o666):
#
# Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
# in PC/launcher.c must also be updated.
#
# In general, the MAGIC_NUMBER should not change for maintenance releases
# although this may be required under exceptional circumstances. When
# each release reaches candidate status, an entry in EXPECTED_MAGIC_NUMBERS
# should be added for this release. This value is tested against the actual
# MAGIC_NUMBER to ensure that if a change is required within a minor
# release, the exception is first discussed with python-dev and relevant
# community stakeholders such as OS distribution package maintainers
# are properly informed of the change.

EXPECTED_MAGIC_NUMBERS = {
(2, 7): 62211,
(3, 5): 3350,
(3, 6): 3379
}

MAGIC_NUMBER = (3390).to_bytes(2, 'little') + b'\r\n'
_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c
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1 change: 0 additions & 1 deletion Lib/importlib/util.py
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Expand Up @@ -4,7 +4,6 @@
from ._bootstrap import _resolve_name
from ._bootstrap import spec_from_loader
from ._bootstrap import _find_spec
from ._bootstrap_external import EXPECTED_MAGIC_NUMBERS
from ._bootstrap_external import MAGIC_NUMBER
from ._bootstrap_external import cache_from_source
from ._bootstrap_external import decode_source
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57 changes: 0 additions & 57 deletions Lib/test/test_importlib/test_release.py
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44 changes: 44 additions & 0 deletions Lib/test/test_importlib/test_util.py
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Expand Up @@ -757,5 +757,49 @@ def test_source_from_cache_path_like_arg(self):
) = util.test_both(PEP3147Tests, util=importlib_util)


class MagicNumberTests:
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Inherit from unittest.TestCase here

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I initially avoided this and followed the test machinery as I wasn't sure about directly importing importlib.util within this test module, but after looking at the way the test specialization works I don't see how this is an issue. Changed in 1e32a1b.

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Yeah, this module does some interesting things to create "real" test classes in different configurations, but we don't need those kinds of tricks for the new test.

"""
Test release compatibility issues relating to importlib
"""
def test_magic_number(self):
"""
Each python minor release should generally have a MAGIC_NUMBER
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I think it would be better to write this as a comment rather than a docstring. If you want, add a one-line docstring, but most test methods don't have docstrings.

that does not change once the release reaches candidate status.

Once a release reaches candidate status, the value of the constant
EXPECTED_MAGIC_NUMBER in this test should be changed.
This test will then check that the actual MAGIC_NUMBER matches
the expected value for the release.

In exceptional cases, it may be required to change the MAGIC_NUMBER
for a maintenance release. In this case the change should be
discussed in python-dev. If a change is required, community
stakeholders such as OS package maintainers must be notified
in advance. Such exceptional releases will then require an
adjustment to this test case.
"""
if sys.version_info.releaselevel not in ('final', 'candidate'):
return
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This can change to a unittest.skipUnless decorator on the testmethod:

@unittest.skipUnless(sys.version_info.release in ('final', 'release'), 'Only check magic number stability for release candidates and later')

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Done in 1e32a1b

EXPECTED_MAGIC_NUMBER = 3379
actual = int.from_bytes(self.util.MAGIC_NUMBER[:2], 'little')

msg = (
"Candidate and final releases require the current "
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I'd start this message with "To avoid breaking backwards compatibility with cached bytecode files that can't be automatically regenerated by the current user, ..."

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Added in 1e32a1b

"importlib.util.MAGIC_NUMBER to match the expected "
"magic number in this test. Set the expected "
"magic number in this test to the current MAGIC_NUMBER to "
"continue with the release.\n\n"
"Changing the MAGIC_NUMBER for a maintenance release "
"requires discussion in python-dev and notification of "
"community stakeholders."
)
self.assertEqual(EXPECTED_MAGIC_NUMBER, actual, msg)


Source_MagicNumberTests = util.specialize_class(
MagicNumberTests, 'Source', None, util=importlib_util
)


if __name__ == '__main__':
unittest.main()
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