gh-155151: Check the recursion limit in CALL_EX_PY and CALL_KW_BOUND_METHOD

[shoutoutuoadi325]

Fixes #155151

Problem

The generic CALL_FUNCTION_EX and CALL_KW reach start_frame, which calls
_Py_EnterRecursivePy() and raises RecursionError before the callee runs.
Their specialized forms end in _PUSH_FRAME, which decrements
py_recursion_remaining without checking it. So once a call site had been
warmed up, the callee was entered and returned normally where the
unspecialized instruction raised — warming a call site changed whether the
target function executed.

Solution

CALL_KW_PY and CALL_BOUND_METHOD_EXACT_ARGS already guard their frame push
with _CHECK_RECURSION_REMAINING. This adds it to the two that were missing
it: CALL_EX_PY and CALL_KW_BOUND_METHOD.

Changes

• Added _CHECK_RECURSION_REMAINING to CALL_EX_PY and CALL_KW_BOUND_METHOD macros in Python/bytecodes.c
• Regenerated opcode metadata and generated cases
• Added regression tests in Lib/test/test_opcache.py
• Added NEWS entry

Testing

• Added test_recursion_check_for_call_ex_py and test_recursion_check_for_call_kw_bound_method tests
• Verified that specialized opcodes now raise RecursionError before entering the callee when the recursion limit is reached
• All existing tests pass

• Issue: CALL_EX_PY and CALL_KW_BOUND_METHOD can bypass RecursionError after specialization #155151

[Copilot]

Pull request overview

This PR fixes a behavioral mismatch at the Python recursion limit between generic call opcodes (CALL_FUNCTION_EX, CALL_KW) and their specialized forms (CALL_EX_PY, CALL_KW_BOUND_METHOD). Previously, once a call site specialized, the specialized fast-path could enter and run the callee in situations where the generic opcode would raise RecursionError before the callee executed.

Changes:

• Added _CHECK_RECURSION_REMAINING guards to the CALL_EX_PY and CALL_KW_BOUND_METHOD macros so low recursion budget triggers deoptimization back to the generic opcode.
• Regenerated interpreter generated code (generated_cases.c.h) and opcode macro metadata to reflect the new uop sequence.
• Added regression tests ensuring warmed (specialized) call sites do not execute the callee at the recursion boundary, plus a NEWS entry.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
Python/bytecodes.c	Inserts _CHECK_RECURSION_REMAINING into the two specialized call macros that could previously bypass the recursion check.
Python/generated_cases.c.h	Regenerated cases include the corresponding deopt-on-low-recursion blocks for the specialized opcodes.
Include/internal/pycore_opcode_metadata.h	Regenerated macro expansion metadata updates uop counts/sequences for the affected opcodes.
Lib/test/test_opcache.py	Adds regression tests to ensure specialization does not change recursion-limit behavior (callee must not run).
Misc/NEWS.d/next/Core_and_Builtins/2026-08-09-05-10-00.gh-issue-155151.b2A2eQ.rst	Documents the behavioral fix in the NEWS entry.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.