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[3.15] gh-150449: Raise ValueError for sqlite3.Blob slices with a negative step - #155773

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[3.15] gh-150449: Raise ValueError for sqlite3.Blob slices with a negative step#155773
serhiy-storchaka merged 2 commits into
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serhiy-storchaka:backport-150450-3.15

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@serhiy-storchaka serhiy-storchaka commented Aug 14, 2026 •
edited by bedevere-app Bot
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Reading or writing a Blob slice with a negative step computed a negative length and failed with SystemError, which means an internal error.
It now raises ValueError.

Empty slices, which select nothing, are still allowed: blob[3:8:-1] returns b"" and assigning b"" to it is a no-op.

Support for negative steps is added in 3.16 by GH-150450.

@serhiy-storchaka
pythongh-150449: Raise ValueError for sqlite3.Blob slices with a nega…
e2272d4 
…tive step

Reading or writing such a slice computed a negative length and failed with
SystemError.  Empty slices, which select nothing, are still allowed.

(cherry picked from commit d9e8d226a3d05ea020256086aee24d21f9792206)
@serhiy-storchaka serhiy-storchaka added needs backport to 3.14 bugs and security fixes needs backport to 3.13 only security fixes labels Aug 14, 2026
@bedevere-app bedevere-app Bot mentioned this pull request Aug 14, 2026
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@bedevere-app bedevere-app Bot added the type-feature A feature request or enhancement label Oct 9, 2026
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serhiy-storchaka enabled auto-merge (squash) October 9, 2026 18:04
@serhiy-storchaka serhiy-storchaka removed needs backport to 3.13 only security fixes type-feature A feature request or enhancement labels Oct 9, 2026
@serhiy-storchaka
serhiy-storchaka merged commit 503560d into python:3.15 Oct 9, 2026
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@miss-islington-app

miss-islington-app Bot commented Oct 9, 2026

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Thanks @serhiy-storchaka for the PR 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

@miss-islington-app

miss-islington-app Bot commented Oct 9, 2026

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Sorry, @serhiy-storchaka, I could not cleanly backport this to 3.14 due to a conflict.

Please backport manually with cherry_picker, see the devguide for more information.

cherry_picker 503560dcadd9eaa42f152115b495143f1fc64ff2 3.14

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serhiy-storchaka deleted the backport-150450-3.15 branch October 9, 2026 18:36
@serhiy-storchaka serhiy-storchaka mentioned this pull request Oct 10, 2026
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bedevere-app Bot commented Oct 10, 2026

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GH-159110 is a backport of this pull request to the 3.14 branch.

@bedevere-app bedevere-app Bot removed the needs backport to 3.14 bugs and security fixes label Oct 10, 2026
serhiy-storchaka added a commit that referenced this pull request Oct 10, 2026
@serhiy-storchaka
[3.14] gh-150449: Raise ValueError for sqlite3.Blob slices with a neg…
15045f4 
…ative step (GH-155773) (GH-159110)

Reading or writing such a slice computed a negative length and failed with
SystemError.  Empty slices, which select nothing, are still allowed.
(cherry picked from commit 503560d)


(cherry picked from commit d9e8d226a3d05ea020256086aee24d21f9792206)
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