• Related Malformed builtin __text_signature__ makes inspect.signature(len/sorted/open) raise ValueError #8383
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Summary

whats_left.py skipped signatures and docstrings for everything written in Rust, and looked at a module one level deep, so a native class counted as present whatever its methods were. It now compares native functions and methods, including the members of classes a module owns, as discussed on #8725.

• These numbers come from a default-feature Linux build. With --features sqlite, which the weekly data job uses, sqlite3 imports and they shift a little: 1,177 items in --signature, 1,541 docstring mismatches, and three unimportable modules instead of four.

What changed

• A module's docstring mismatches are recorded on their own. They were kept only when the module also had missing items or signature mismatches, so annotationlib, base64, ntpath and _ctypes reported none.
• A builtin type method that differs is a mismatch, not a missing method. Such a method was listed under "builtin items", the section the website's builtin_items.csv is built from, with both extra_info dicts as the reason. Without this, lifting the skip below turns that section's single line into 455.
• Native functions and methods are compared. The _signature_is_builtin skip dates from cc2c46b (2021, Builtin functions and methods lack a .__text_signature__ property #2410), when RustPython had no __text_signature__ for builtins.
• Native classes are opened. 438 classes and 4,062 members, compared as Class.member. A class counts as native when it has no __firstlineno__, which a class statement records, and no Python functions of its own, which rules out namedtuple-style classes made by type(). RustPython follows the CPython list instead of deciding again; a member it only inherits, and that reads differently, is listed with (inherited), and a name implemented as something else, such as _sha3's hash functions, is left to its own line.
• Ownership comes from the class dictionary. Comparing values, as attr_is_not_inherited() did, dropped 394 of CPython's own class attributes before RustPython was asked about them, 94 of them None-valued like ast.FunctionDef.returns, and took every inherited classmethod, __subclasshook__ for one, for a class's own. An inherited member that reads the same as CPython's own one, like dict_items.__doc__, now counts as present.
• A module that exists but cannot be imported is reported as such. dir_of_mod_or_error() ran dir() on the exception import_module() returns, so sqlite3 alone filled 198 "missing item" lines and CPython's _ios_support was compared as a module holding ImportError's attributes.

Notes

• The # builtin items section is unchanged and # modules only gains the four "exists but not importable" lines, so both CSVs the weekly job builds are identical. # stdlib items gains 156 class-member lines and loses the 533 that came from those four modules.
• __builtins__ is no longer compared. inspect.signature() evals defaults in the owning module's namespace and eval() adds __builtins__ there, so CPython's builtins gained one once list.index had been inspected.
• CPython's __annotations_cache__ and __vectorcalloffset__ are left out as implementation details. The first alone accounts for 112 members on ast nodes.
• 54 of the new lines are (inherited): members RustPython inherits with a different signature or docstring, __sizeof__ for 13 of them.
• A full run takes two to three times as long, about 5s to about 12s here, and the generated file grows from 1.2 MB to 2.0 MB.

Assisted-by: Claude Code:claude-opus-5

Summary by CodeRabbit

• Bug Fixes
  • Improved API comparison results by distinguishing missing methods from signature and documentation mismatches.
  • Expanded native and inherited member inspection for more complete compatibility checks.
  • Included built-in callable signatures in comparison results.
  • Improved handling and reporting of module inspection failures.
  • Skipped non-class entries that are not applicable to API comparisons.
  • Modules are now marked complete only when no missing or signature mismatches remain.