[`pep8_naming`] Avoid false positives on standard library functions with uppercase names (`N802`) by w0nder1ng · Pull Request #18907 · astral-sh/ruff

w0nder1ng · 2025-06-24T02:02:54Z

Summary

This change prevents the visit_* methods of ast.NodeVisitor/NodeTransformer and the do_* methods of http.server.BaseHTTPRequestHandler from triggering N802. See #9400 for more information.

In Lib/ast.py:

class NodeVisitor(object):
    def visit(self, node):
        """Visit a node."""
        method = 'visit_' + node.__class__.__name__
        visitor = getattr(self, method, self.generic_visit)
        return visitor(node)

Example usage

from ast import NodeVisitor

class Visitor(NodeVisitor):
    def visit_Constant(self, node):
        print(f"visited a constant with value {node.value}")

Previously, this would trigger a N802 violation, even though the uppercase name is the intended way of using those subclasses.

Test Plan

I added tests to pep8_naming/N802.py.

…http.server.BaseHTTPRequestHandler from triggering N802

github-actions · 2025-06-24T02:11:56Z

`ruff-ecosystem` results

Linter (stable)

ℹ️ ecosystem check detected linter changes. (+3 -8 violations, +0 -0 fixes in 4 projects; 51 projects unchanged)

apache/airflow (+0 -6 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --no-preview --select ALL

- airflow-core/src/airflow/utils/scheduler_health.py:36:9: N802 Function name `do_GET` should be lowercase
- dev/breeze/src/airflow_breeze/commands/release_management_commands.py:3387:17: N802 Function name `visit_FunctionDef` should be lowercase
- scripts/ci/pre_commit/check_deferrable_default.py:45:9: N802 Function name `visit_FunctionDef` should be lowercase
- scripts/in_container/run_template_fields_check.py:52:9: N802 Function name `visit_FunctionDef` should be lowercase
- scripts/in_container/run_template_fields_check.py:57:9: N802 Function name `visit_Assign` should be lowercase
- scripts/in_container/run_template_fields_check.py:66:9: N802 Function name `visit_AnnAssign` should be lowercase

bokeh/bokeh (+0 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --no-preview --select ALL

- tests/support/plugins/file_server.py:59:9: N802 Function name `do_GET` should be lowercase

langchain-ai/langchain (+2 -0 violations, +0 -0 fixes)

+ libs/cli/langchain_cli/namespaces/migrate/generate/utils.py:23:48: RUF100 [*] Unused `noqa` directive (unused: `N802`)
+ libs/cli/langchain_cli/namespaces/migrate/generate/utils.py:42:50: RUF100 [*] Unused `noqa` directive (unused: `N802`)

latchbio/latch (+1 -1 violations, +0 -0 fixes)

- src/latch_cli/auth/oauth2.py:89:17: N802 Function name `do_GET` should be lowercase
+ src/latch_cli/centromere/ast_parsing.py:32:58: RUF100 [*] Unused `noqa` directive (unused: `N802`)

Changes by rule (2 rules affected)

code	total	+ violation	- violation	+ fix	- fix
N802	8	0	8	0	0
RUF100	3	3	0	0	0

Linter (preview)

ℹ️ ecosystem check detected linter changes. (+3 -8 violations, +0 -0 fixes in 4 projects; 51 projects unchanged)

apache/airflow (+0 -6 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview --select ALL

- airflow-core/src/airflow/utils/scheduler_health.py:36:9: N802 Function name `do_GET` should be lowercase
- dev/breeze/src/airflow_breeze/commands/release_management_commands.py:3387:17: N802 Function name `visit_FunctionDef` should be lowercase
- scripts/ci/pre_commit/check_deferrable_default.py:45:9: N802 Function name `visit_FunctionDef` should be lowercase
- scripts/in_container/run_template_fields_check.py:52:9: N802 Function name `visit_FunctionDef` should be lowercase
- scripts/in_container/run_template_fields_check.py:57:9: N802 Function name `visit_Assign` should be lowercase
- scripts/in_container/run_template_fields_check.py:66:9: N802 Function name `visit_AnnAssign` should be lowercase

bokeh/bokeh (+0 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview --select ALL

- tests/support/plugins/file_server.py:59:9: N802 Function name `do_GET` should be lowercase

langchain-ai/langchain (+2 -0 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview

+ libs/cli/langchain_cli/namespaces/migrate/generate/utils.py:23:48: RUF100 [*] Unused `noqa` directive (unused: `N802`)
+ libs/cli/langchain_cli/namespaces/migrate/generate/utils.py:42:50: RUF100 [*] Unused `noqa` directive (unused: `N802`)

latchbio/latch (+1 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview

- src/latch_cli/auth/oauth2.py:89:17: N802 Function name `do_GET` should be lowercase
+ src/latch_cli/centromere/ast_parsing.py:32:58: RUF100 [*] Unused `noqa` directive (unused: `N802`)

Changes by rule (2 rules affected)

code	total	+ violation	- violation	+ fix	- fix
N802	8	0	8	0	0
RUF100	3	3	0	0	0

MichaReiser · 2025-06-24T08:23:24Z

I don't think the special handling for NodeVisitor is necessary because typeshed defines all methods on NodeVisitor and, therefore, using @typing.override works (mypy)

Special casing the http handler seems fine, while unfortunate

w0nder1ng · 2025-06-25T00:01:59Z

@typing.override was added in 3.12, so it's not available in 3.11 or earlier, which is where I ran into this issue. Could the NodeVisitor check be gated behind python version < 3.12?

w0nder1ng · 2025-07-07T04:22:25Z

@MichaReiser is this an acceptable solution?

ntBre

This looks reasonable to me if it's okay with @MichaReiser. I just had a few small suggestions.

Before 3.12 I think users could still get @override from typing_extensions, but I'm not sure if that would be a better approach.

crates/ruff_linter/src/rules/pep8_naming/rules/invalid_function_name.rs

crates/ruff_linter/src/rules/pep8_naming/mod.rs

crates/ruff_linter/src/rules/pep8_naming/rules/invalid_function_name.rs

* dcreager/merge-arguments: (223 commits) fix docs Combine CallArguments and CallArgumentTypes [ty] Sync vendored typeshed stubs (#19334) [`refurb`] Make example error out-of-the-box (`FURB122`) (#19297) [refurb] Make example error out-of-the-box (FURB177) (#19309) [ty] ignore errors when reformatting codemodded typeshed (#19332) [ty] Provide docstrings for stdlib APIs when hovering over them in an IDE (#19311) [ty] Add virtual files to the only project database (#19322) Add t-string fixtures for rules that do not need to be modified (#19146) [ty] Remove `FileLookupError` (#19323) [ty] Fix handling of metaclasses in `object.<CURSOR>` completions [ty] Use an interval map for scopes by expression (#19025) [ty] List all `enum` members (#19283) [ty] Handle configuration errors in LSP more gracefully (#19262) [ty] Use python version and path from Python extension (#19012) [`pep8_naming`] Avoid false positives on standard library functions with uppercase names (`N802`) (#18907) Update Rust crate toml to 0.9.0 (#19320) [ty] Fix server version (#19284) Update NPM Development dependencies (#19319) Update taiki-e/install-action action to v2.56.13 (#19317) ...

-astral-sh/ruff#18907 - https://github.com/astral-sh/ruff/releases/tag/0.12.4

Prevent special methods of ast.NodeVisitor, ast.NodeTransformer, and …

044fd08

…http.server.BaseHTTPRequestHandler from triggering N802

MichaReiser added the rule Implementing or modifying a lint rule label Jun 24, 2025

w0nder1ng added 2 commits July 6, 2025 23:56

add version gate for ast.NodeVisitor and ast.NodeTransformer exceptions

8910340

update tests and add test for python <3.12

429cf92

ntBre reviewed Jul 9, 2025

View reviewed changes

use ruff_python_semantic::analyze::class::any_base_class and fix nits

0ff1af5

MichaReiser reviewed Jul 11, 2025

View reviewed changes

crates/ruff_linter/src/rules/pep8_naming/rules/invalid_function_name.rs Outdated Show resolved Hide resolved

w0nder1ng and others added 5 commits July 13, 2025 13:47

gate NodeVisitor lint with typing extensions instead of python version

bc05a00

fix lint

1140815

Simplify

df8d397

Delete typing extensions test case

7be4292

Use early return

76bea00

MichaReiser enabled auto-merge (squash) July 14, 2025 08:24

MichaReiser merged commit 26f736b into astral-sh:main Jul 14, 2025
34 checks passed

BrewTestBot mentioned this pull request Jul 17, 2025

ruff 0.12.4 Homebrew/homebrew-core#230452

Merged

dangotbanned added a commit to narwhals-dev/narwhals that referenced this pull request Jul 18, 2025

ci: bump ruff==0.12.4

e6964e1

-astral-sh/ruff#18907 - https://github.com/astral-sh/ruff/releases/tag/0.12.4

dangotbanned mentioned this pull request Jul 18, 2025

ci: bump ruff==0.12.4 narwhals-dev/narwhals#2845

Merged

10 tasks

dscorbett mentioned this pull request Jul 18, 2025

N802 false positives for CGIHTTPRequestHandler and SimpleHTTPRequestHandler #19422

Closed

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[`pep8_naming`] Avoid false positives on standard library functions with uppercase names (`N802`)#18907

[`pep8_naming`] Avoid false positives on standard library functions with uppercase names (`N802`)#18907
MichaReiser merged 9 commits intoastral-sh:mainfrom
w0nder1ng:n802_ast_visit

w0nder1ng commented Jun 24, 2025

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w0nder1ng commented Jun 24, 2025

Summary

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ruff-ecosystem results

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w0nder1ng commented Jun 25, 2025

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