ast: fix identifier interning by widehyo1 · Pull Request #8361 · RustPython/RustPython · GitHub

This PR follows our AI policy

Summary

Ensure that identifier fields produced while converting parsed AST nodes use
interned Python strings, matching CPython behavior. In particular, this fixes
Name.id and function definition name fields.

This restores identity-sensitive behavior used by copy.replace() and removes
the three test_ast expected-failure markers that now pass. Add regression
coverage for expression, synchronous-function, and async-function identifiers.

Testing

uv tool run prek run --all-files
cargo fmt --check
cargo run --release Lib/test/test_ast/test_ast.py
- 199 tests passed
- 7 skipped
- 21 expected failures
cargo run -- extra_tests/snippets/stdlib_ast.py
cargo clippy -p rustpython-stdlib --all-targets
the configured workspace test suite

AI assistance: Codex:gpt-5.6-sol

Summary by CodeRabbit

Bug Fixes
- Fixed AST identifier and function name conversion so id/name values match the expected representation and preserve correct identity semantics.
- Improved AST node copy/replace behavior to retain the original identifier and context while dropping unrelated dynamically added attributes.
Tests
- Added regression coverage for identifier interning, function and async function name handling, and AST copy/replace semantics to align with CPython behavior.

Ensure parsed name and function identifier fields use interned strings, matching CPython behavior. Assisted-by: Codex:gpt-5.6-sol

No actionable comments were generated in the recent review. 🎉

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📥 Commits

Reviewing files that changed from the base of the PR and between 2b3e622 and dd94804.

📒 Files selected for processing (1)

extra_tests/snippets/stdlib_ast.py

📝 Walkthrough

Walkthrough

AST expression and function-definition name conversion now uses AST-aware serialization, with regression tests covering interned identifier identity and copy.replace behavior.

Changes

AST identifier serialization

Layer / File(s)	Summary
AST-aware identifier serialization and regression coverage crates/vm/src/stdlib/_ast/expression.rs, crates/vm/src/stdlib/_ast/statement.rs, extra_tests/snippets/stdlib_ast.py	ExprName.id and StmtFunctionDef.name now use ast_to_object; tests verify interned identities and preservation of id/ctx during copy.replace.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

RustPython/RustPython#6986: Related AST identifier/name interning behavior and conversion tests.

🚥 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 is concise and accurately summarizes the main change: fixing AST identifier interning 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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📦 Library Dependencies

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

[x] lib: cpython/Lib/ast.py
[x] lib: cpython/Lib/_ast_unparse.py
[x] test: cpython/Lib/test/test_unparse.py
[x] test: cpython/Lib/test/test_type_comments.py

dependencies:

ast

dependent tests: (149 tests)

ast: test_ast test_builtin test_compile test_compiler_codegen test_dis test_fstring test_future_stmt test_peepholer test_peg_generator test_site test_ssl test_type_comments test_ucn test_unparse
- annotationlib: test_annotationlib test_functools test_grammar test_inspect test_reprlib test_type_annotations test_type_params test_typing
  - dataclasses: test__colorize test_copy test_ctypes test_enum test_genericalias test_patma test_pprint test_pydoc test_regrtest test_zoneinfo
  - inspect: test_abc test_argparse test_asyncgen test_buffer test_clinic test_code test_collections test_coroutines test_decimal test_generators test_monitoring test_ntpath test_operator test_posixpath test_signal test_sqlite3 test_traceback test_turtle test_types test_unittest test_yield_from test_zipimport test_zipimport_support
- dbm.dumb: test_dbm_dumb
- inspect:
  - bdb: test_bdb test_pdb
  - cmd: test_cmd
  - importlib.metadata: test_importlib
  - pkgutil: test_pkgutil test_pyrepl test_runpy
  - rlcompleter: test_pyrepl test_rlcompleter
  - trace: test_trace
  - xmlrpc.server: test_docxmlrpc test_xmlrpc
- pyclbr: test_pyclbr
- traceback: test_asyncio test_code_module test_contextlib test_contextlib_async test_dictcomps test_exceptions test_http_cookiejar test_importlib test_iter test_listcomps test_pyexpat test_setcomps test_socket test_subprocess test_sys test_threadedtempfile test_threading test_unittest test_with
  - concurrent.futures.process: test_compileall test_concurrent_futures
  - http.cookiejar: test_urllib2
  - logging: test_asyncio test_hashlib test_logging test_support test_urllib2net
  - multiprocessing: test_asyncio test_concurrent_futures test_fcntl test_memoryview test_multiprocessing_main_handling test_re
  - py_compile: test_cmd_line_script test_importlib test_modulefinder test_py_compile
  - socketserver: test_imaplib test_socketserver test_wsgiref
  - threading: test_android test_asyncio test_bytes test_bz2 test_concurrent_futures test_context test_ctypes test_email test_external_inspection test_fork1 test_frame test_ftplib test_gc test_httplib test_httpservers test_importlib test_io test_ioctl test_itertools test_largefile test_linecache test_opcache test_pathlib test_poll test_poplib test_pyrepl test_queue test_robotparser test_sched test_smtplib test_super test_syslog test_termios test_threading_local test_time test_urllib2_localnet test_weakref test_winreg test_zstd
  - timeit: test_timeit

Legend:

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

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@extra_tests/snippets/stdlib_ast.py`:
- Line 43: Move the copy import from its current position after executable
top-level statements into the module’s existing top-level import block,
preserving the surrounding import ordering and leaving executable code
unchanged.

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Review profile: CHILL

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Run ID: e7382c2a-71e2-4390-b543-ea7a719d828a

📥 Commits

Reviewing files that changed from the base of the PR and between 28454cc and 2b3e622.

⛔ Files ignored due to path filters (1)

Lib/test/test_ast/test_ast.py is excluded by !Lib/**

📒 Files selected for processing (3)

crates/vm/src/stdlib/_ast/expression.rs
crates/vm/src/stdlib/_ast/statement.rs
extra_tests/snippets/stdlib_ast.py

👍

Fix AST identifier interning

2b3e622

Ensure parsed name and function identifier fields use interned strings, matching CPython behavior. Assisted-by: Codex:gpt-5.6-sol

coderabbitai Bot reviewed Jul 25, 2026

View reviewed changes

Comment thread extra_tests/snippets/stdlib_ast.py Outdated

Apply PEP 8 import ordering

dd94804

youknowone added the z-ca-2026 Tag to track Contribution Academy 2026 label Jul 25, 2026

youknowone approved these changes Jul 25, 2026

View reviewed changes

youknowone merged commit 4a80f2e into RustPython:main Jul 25, 2026
27 checks passed

widehyo1 deleted the fix-ast-identifier-interning branch July 26, 2026 04:26

ast: fix identifier interning by widehyo1 · Pull Request #8361 · RustPython/RustPython · GitHub

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ast: fix identifier interning - #8361

ast: fix identifier interning#8361
youknowone merged 2 commits into
RustPython:mainfrom
widehyo1:fix-ast-identifier-interning

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ast: fix identifier interning by widehyo1 · Pull Request #8361 · RustPython/RustPython · GitHub

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ast: fix identifier interning - #8361

ast: fix identifier interning#8361youknowone merged 2 commits intoRustPython:mainRustPython/RustPython:mainfrom widehyo1:fix-ast-identifier-interningwidehyo1/RustPython:fix-ast-identifier-interningCopy head branch name to clipboard

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ast: fix identifier interning#8361
youknowone merged 2 commits into
RustPython:mainfrom
widehyo1:fix-ast-identifier-interning

widehyo1 commented Jul 25, 2026 •
edited by coderabbitai Bot
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