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GeezerVison is showing github.com — gh-156091: Fix crash compiling deeply nested inlined comprehensions by iritkatriel · Pull Request #156957 · python/cpython

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@iritkatriel

@iritkatriel iritkatriel commented Sep 4, 2026 •
edited by bedevere-app Bot
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Count inlined-comprehension SETUP_FINALLY handlers toward CO_MAXBLOCKS so the compiler raises SyntaxError instead of overflowing the except stack.

Fixes #156091.

  • Issue: Compiler crash: inlined comprehensions overflow _PyCfgExceptStack, bypassing the u_nfblocks block-nesting limit #156091

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@iritkatriel @cursoragent
pythongh-156091: Fix crash compiling deeply nested inlined comprehens…
9044124 
…ions

Count inlined-comprehension SETUP_FINALLY handlers toward CO_MAXBLOCKS so
the compiler raises SyntaxError instead of overflowing the except stack.

Co-authored-by: Cursor <[email protected]>
@iritkatriel
iritkatriel requested a review from markshannon as a code owner September 4, 2026 18:35
@bedevere-app bedevere-app Bot mentioned this pull request Sep 4, 2026
Compiler crash: inlined comprehensions overflow _PyCfgExceptStack, bypassing the u_nfblocks block-nesting limit #156091
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@bedevere-app bedevere-app Bot added the awaiting core review label Sep 4, 2026
@iritkatriel iritkatriel added needs backport to 3.13 only security fixes needs backport to 3.14 bugs and security fixes needs backport to 3.15 bugs and security fixes type-crash A hard crash of the interpreter, possibly with a core dump and removed awaiting core review labels Sep 4, 2026
@iritkatriel
iritkatriel requested review from JelleZijlstra and carljm September 4, 2026 18:36
JelleZijlstra
JelleZijlstra approved these changes Sep 5, 2026
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@bedevere-app bedevere-app Bot added the awaiting merge label Sep 5, 2026
@iritkatriel
Merge branch 'main' into pythongh-156091
1385ed4
@iritkatriel
iritkatriel enabled auto-merge (squash) September 5, 2026 15:30
@iritkatriel
iritkatriel merged commit 14a93f4 into python:main Sep 5, 2026
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@miss-islington-app

miss-islington-app Bot commented Sep 5, 2026

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Thanks @iritkatriel for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14, 3.15.
🐍🍒⛏🤖
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@bedevere-app bedevere-app Bot removed the awaiting merge label Sep 5, 2026
@bedevere-app

bedevere-app Bot commented Sep 5, 2026

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GH-156992 is a backport of this pull request to the 3.15 branch.
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@bedevere-app bedevere-app Bot removed the needs backport to 3.15 bugs and security fixes label Sep 5, 2026
@miss-islington-app

miss-islington-app Bot commented Sep 5, 2026

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Sorry, @iritkatriel, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 14a93f4d91edf767e7b35413127cfcd6a2806983 3.13
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@miss-islington-app miss-islington-app Bot assigned iritkatriel Sep 5, 2026
@bedevere-app

bedevere-app Bot commented Sep 5, 2026

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GH-156993 is a backport of this pull request to the 3.14 branch.
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@bedevere-app bedevere-app Bot removed the needs backport to 3.14 bugs and security fixes label Sep 5, 2026
iritkatriel pushed a commit that referenced this pull request Sep 5, 2026
@miss-islington
[3.14] gh-156091: Fix crash compiling deeply nested inlined comprehen…
dd36d01 
…sions (GH-156957) (#156993)
@iritkatriel iritkatriel mentioned this pull request Sep 6, 2026
[3.13] gh-156091: Fix crash compiling deeply nested inlined comprehensions (GH-156957) #157050
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@bedevere-app

bedevere-app Bot commented Sep 6, 2026

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GH-157050 is a backport of this pull request to the 3.13 branch.
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@bedevere-app bedevere-app Bot removed the needs backport to 3.13 only security fixes label Sep 6, 2026
clin1234 pushed a commit to clin1234/cpython that referenced this pull request Sep 12, 2026
@iritkatriel @clin1234
pythongh-156091: Fix crash compiling deeply nested inlined comprehens…
86c03f3 
…ions (python#156957)
iritkatriel added a commit that referenced this pull request Sep 17, 2026
@iritkatriel @cursoragent
[3.13] gh-156091: Fix crash compiling deeply nested inlined comprehen…
d7657d0 
…sions (GH-156957) (#157050)

Count inlined-comprehension SETUP_FINALLY handlers toward CO_MAXBLOCKS.
Manual backport of 14a93f4 / GH-156993; 3.13 still has this code in compile.c.

Co-authored-by: Cursor <[email protected]>
serhiy-storchaka pushed a commit that referenced this pull request Oct 10, 2026
@miss-islington @iritkatriel
[3.15] gh-156091: Fix crash compiling deeply nested inlined comprehen…
845fb34 
…sions (GH-156957) (GH-156992)

(cherry picked from commit 14a93f4)

Co-authored-by: Irit Katriel <[email protected]>
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Reviewers

@JelleZijlstra JelleZijlstra JelleZijlstra approved these changes
@markshannon markshannon Awaiting requested review from markshannon markshannon is a code owner
@carljm carljm Awaiting requested review from carljm

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@iritkatriel iritkatriel

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type-crash A hard crash of the interpreter, possibly with a core dump

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Compiler crash: inlined comprehensions overflow _PyCfgExceptStack, bypassing the u_nfblocks block-nesting limit

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@iritkatriel @JelleZijlstra
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