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Drop int() delegation to __trunc__#7703

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youknowone merged 1 commit intoRustPython:mainfrom
changjoon-park:fix-int-trunc-delegation
Apr 28, 2026
Merged

Drop int() delegation to __trunc__#7703
youknowone merged 1 commit intoRustPython:mainfrom
changjoon-park:fix-int-trunc-delegation

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@changjoon-park changjoon-park commented Apr 27, 2026 •
edited by coderabbitai Bot
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Background

CPython 3.14 fully removed the long-deprecated delegation from int() to __trunc__. Classes that want to support int(x) must implement __int__ or __index__; math.trunc(x) continues to use __trunc__.

RustPython still delegated to __trunc__ (with a DeprecationWarning) inside PyObject::try_int, so int(JustTrunc()) returned the truncated value instead of raising TypeError.

Repro

class JustTrunc:
    def __trunc__(self): return 42

int(JustTrunc())
# CPython 3.14:    TypeError: int() argument must be a string, a bytes-like object or a real number, not 'JustTrunc'
# RustPython:      42 (with DeprecationWarning)   (before this PR)

Fix

Delete the __trunc__ branch in PyObject::try_int (crates/vm/src/protocol/number.rs). The fall-through reaches the existing TypeError arm.

math.trunc() is unaffected — it goes through the __trunc__ method directly, not through try_int.

Tests unmasked

  • test_int.IntTestCases.test_intconversion (covers int(JustTrunc()) raising TypeError)

Verification

  • CPython 3.14.4 byte-identical for int(JustTrunc()) (TypeError), int(IntOverridesTrunc()) (uses __int__ → 42), math.trunc(T()) (still uses __trunc__ → 100)
  • No regressions across 8 modules (~2,022 tests): test_int, test_math, test_decimal, test_descr, test_class, test_inspect, test_typing, test_unittest.testmock.testmagicmethods

Summary by CodeRabbit

  • Changes
    • Removed __trunc__ method delegation from integer conversion. The int() function will no longer attempt to use the __trunc__ method on objects.
    • Removed associated deprecation warnings previously issued during integer conversion.

@changjoon-park
Drop int() delegation to __trunc__
82816b8 
CPython 3.14 fully removed the long-deprecated fallback from int() to
__trunc__. Classes that want int(x) support must implement __int__ or
__index__; math.trunc(x) continues to use __trunc__.

Delete the __trunc__ branch in PyObject::try_int so a class with only
__trunc__ now reaches the existing TypeError arm, matching CPython.

Unmasks test_int.IntTestCases.test_intconversion.
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coderabbitai Bot commented Apr 27, 2026 •
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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info
⚙️ Run configuration

Configuration used: Path: .coderabbit.yml

Review profile: CHILL

Plan: Pro

Run ID: 71cd4799-fa94-4a60-bea2-3a3e5c67b09d

📥 Commits

Reviewing files that changed from the base of the PR and between 1d42ee5 and 82816b8.

⛔ Files ignored due to path filters (1)
  • Lib/test/test_int.py is excluded by !Lib/**
📒 Files selected for processing (1)
  • crates/vm/src/protocol/number.rs
💤 Files with no reviewable changes (1)
  • crates/vm/src/protocol/number.rs
📝 Walkthrough

Walkthrough

The PyObject::try_int method removes support for delegating to the __trunc__ special method during integer conversion. The code that checked for __trunc__, emitted deprecation warnings, and invoked the method is now deleted, simplifying the conversion logic.

Changes

Cohort / File(s) Summary
Integer Conversion Deprecation Removal
crates/vm/src/protocol/number.rs		 Removes 14 lines of code that delegated int() conversion to __trunc__ method, including deprecation warning and return value validation logic.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Poem

🐰 A deprecation fades away,
__trunc__ has had its day,
Simpler paths now pave the way,
For int() conversions—hooray! ✨

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check name Status Explanation
Description Check ✅ Passed Check skipped - CodeRabbit’s high-level summary is enabled.
Title check ✅ Passed The title accurately and directly describes the main change: removing int() delegation to trunc in the codebase, matching the PR's primary objective of aligning with CPython 3.14 behavior.
Docstring Coverage ✅ Passed No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check ✅ Passed Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check ✅ Passed Check skipped because no linked issues were found for this pull request.

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github-actions Bot commented Apr 27, 2026

📦 Library Dependencies

The following Lib/ modules were modified. Here are their dependencies:

[x] lib: cpython/Lib/_pylong.py
[ ] test: cpython/Lib/test/test_int.py (TODO: 4)
[x] test: cpython/Lib/test/test_long.py (TODO: 4)
[x] test: cpython/Lib/test/test_int_literal.py

dependencies:

  • int

dependent tests: (no tests depend on int)

Legend:

  • [+] path exists in CPython
  • [x] up-to-date, [ ] outdated

ShaharNaveh
ShaharNaveh approved these changes Apr 27, 2026
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🚀

@youknowone youknowone merged commit e5f2d2d into RustPython:main Apr 28, 2026
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@ShaharNaveh ShaharNaveh ShaharNaveh approved these changes

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3 participants

@changjoon-park @ShaharNaveh @youknowone