[cmaloney]

BytesIO.write() at a position near sys.maxsize raised SystemError ("Negative size passed to PyBytes_FromStringAndSize") because the overallocated buffer size could exceed PY_SSIZE_T_MAX. Check the computed allocation, not only the requested size.

BytesIO.truncate() converted its argument with PyLong_AsLong(), which rejects sizes above 2**31 - 1 on Windows where C long is 32-bit. Use PyNumber_AsSsize_t() like the Py_ssize_t Argument Clinic converter it used before.

• Issue: BytesIO and StringIO issues with large sizes #160781

[StanFromIreland]

In the future, it's fine to handle this with StringIO and put them in the same news entry.

[miss-islington-app]

Thanks @cmaloney for the PR, and @StanFromIreland for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14, 3.15.
🐍🍒⛏🤖

[bedevere-app]

GH-160891 is a backport of this pull request to the 3.15 branch.

[bedevere-app]

GH-160892 is a backport of this pull request to the 3.14 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot x86 Debian Installed with X 3.14 (tierless) has failed when building commit daccca0.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1793/builds/2045) and take a look at the build logs.
4. Check if the failure is related to this commit (daccca0) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1793/builds/2045

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File �[35m"/buildbot/buildarea/3.14.ware-debian-x86.installed/build/target/lib/python3.14/test/test_memoryio.py"�[0m, line �[35m571�[0m, in �[35mtest_issue141311�[0m
    self.assertEqual(�[31mmemio.getvalue�[0m�[1;31m()�[0m, b"")
                     �[31m~~~~~~~~~~~~~~�[0m�[1;31m^^�[0m
  File �[35m"/buildbot/buildarea/3.14.ware-debian-x86.installed/build/target/lib/python3.14/_pyio.py"�[0m, line �[35m901�[0m, in �[35mgetvalue�[0m
    return bytes(self._buffer)
�[1;35mOverflowError�[0m: �[35mbyte string is too large�[0m

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot ARM Raspbian 3.14 (tier-3) has failed when building commit daccca0.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1689/builds/2102) and take a look at the build logs.
4. Check if the failure is related to this commit (daccca0) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1689/builds/2102

Failed tests:

• test_memoryio

Failed subtests:

• test_issue141311 - test.test_memoryio.PyBytesIOTest.test_issue141311

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/var/lib/buildbot/workers/3.14.gps-raspbian.nondebug/build/Lib/test/test_memoryio.py", line 571, in test_issue141311
    self.assertEqual(memio.getvalue(), b"")
                     ~~~~~~~~~~~~~~^^
  File "/var/lib/buildbot/workers/3.14.gps-raspbian.nondebug/build/Lib/_pyio.py", line 901, in getvalue
    return bytes(self._buffer)
OverflowError: byte string is too large

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot x86 Debian Non-Debug with X 3.14 (tierless) has failed when building commit daccca0.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1687/builds/1999) and take a look at the build logs.
4. Check if the failure is related to this commit (daccca0) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1687/builds/1999

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File �[35m"/buildbot/buildarea/3.14.ware-debian-x86.nondebug/build/Lib/test/test_memoryio.py"�[0m, line �[35m571�[0m, in �[35mtest_issue141311�[0m
    self.assertEqual(�[31mmemio.getvalue�[0m�[1;31m()�[0m, b"")
                     �[31m~~~~~~~~~~~~~~�[0m�[1;31m^^�[0m
  File �[35m"/buildbot/buildarea/3.14.ware-debian-x86.nondebug/build/Lib/_pyio.py"�[0m, line �[35m901�[0m, in �[35mgetvalue�[0m
    return bytes(self._buffer)
�[1;35mOverflowError�[0m: �[35mbyte string is too large�[0m

[StanFromIreland]

Fix for the test in #160903.