additional ruff fixes by Light2Dark · Pull Request #9132 · marimo-team/marimo

Light2Dark · 2026-04-10T17:26:49Z

📝 Summary

Most of these are ruff autofixes, which can be done with ruff check --unsafe-fixes --fix. I removed ones that were safe with AI help.

I then went in again with Claude, and GPT to review the PR, and offer cleanup of the code. These are the last commits.

📋 Pre-Review Checklist

For large changes, or changes that affect the public API: this change was discussed or approved through an issue, on Discord, or the community discussions (Please provide a link if applicable).
Any AI generated code has been reviewed line-by-line by the human PR author, who stands by it.
Video or media evidence is provided for any visual changes (optional).

✅ Merge Checklist

I have read the contributor guidelines.
Documentation has been updated where applicable, including docstrings for API changes.
Tests have been added for the changes made.

vercel · 2026-04-10T17:26:56Z

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Apr 10, 2026 6:05pm

Copilot

Pull request overview

This PR applies a broad set of Ruff-driven refactors across the marimo Python codebase and its test suite, primarily to satisfy newly-enabled (or no-longer-ignored) lint rules. The changes are largely mechanical (container literals, comprehension simplifications, raise usage, startswith/endswith tuples, iterating dicts directly, etc.) and intended to reduce lint noise and improve consistency.

Changes:

Refactor many Python expressions to preferred idioms (e.g., {...}/(...)/{k: v} literals, set/dict comprehensions, next(iter(...)), direct dict iteration, tuple-form startswith/endswith).
Replace raise e with bare raise in exception handlers to preserve tracebacks.
Update Ruff configuration (pyproject.toml) by removing several ignores now that corresponding violations have been addressed.

Reviewed changes

Copilot reviewed 132 out of 132 changed files in this pull request and generated no comments.

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File	Description
tests/_utils/test_parse_dataclass.py	Use tuple literal instead of `tuple([...])` in test data.
tests/_utils/test_health_utils.py	Use list literal `[]` instead of `list()` in tests.
tests/_utils/test_formatter.py	Iterate dict directly rather than `.keys()` in tests.
tests/_utils/test_flatten.py	Replace unnecessary `tuple()/dict()` calls with literals in tests.
tests/_sql/test_sql_parse.py	Rename unused `error` binding to `_error` in tests.
tests/_session/test_file_change_handler.py	Replace `list(...)[0]` with `next(iter(...))` in tests.
tests/_session/state/test_serialize_session.py	Use empty tuple literal `()` in cache key construction.
tests/_server/test_file_manager.py	Replace `list(...)[0]` with `next(iter(...))` in tests.
tests/_server/test_asgi.py	Use tuple-form `.endswith((...))` in tests.
tests/_server/api/endpoints/test_ws.py	Replace `list(...)[0]` with `next(iter(...))` in tests.
tests/_server/api/endpoints/test_execution.py	Iterate dict directly instead of `.keys()` in tests.
tests/_server/ai/test_mcp.py	Fix implicit-optional type hints and unused variables in tests.
tests/_save/test_cache.py	Use bare `raise`; rename unused `state/set_state` where appropriate.
tests/_save/store/test_store.py	Prefer `key in dict` over `key in dict.keys()` in tests.
tests/_runtime/test_virtual_file.py	Iterate dict/set-like containers directly; avoid `list(...)[0]` in tests.
tests/_runtime/test_runtime.py	Prefer set literals and generator forms over unnecessary allocations in tests.
tests/_runtime/test_edges.py	Rename unused tuple unpack members to `_children/_parents` in tests.
tests/_runtime/test_dataflow.py	Prefer set literals/comprehensions over `set([...])` in tests.
tests/_runtime/test_control_flow.py	Prefer set literal over `set([...])` in tests.
tests/_runtime/test_complete.py	Fix bug: actually `raise RuntimeError(...)` in test helper logic.
tests/_runtime/reload/test_autoreload.py	Avoid redundant `list(set(list(...)))` patterns in tests.
tests/_runtime/packages/test_module_registry.py	Prefer set literal over `set([...])` in tests.
tests/_pyodide/test_bootstrap.py	Rename unused `session` binding to `_session` in tests.
tests/_plugins/ui/_impl/test_table.py	Prefer set literal `{...}` in invalid-data test case.
tests/_plugins/ui/_impl/tables/test_polars_table.py	Prefer set literals in complex-data fixtures.
tests/_plugins/ui/_impl/tables/test_pandas_table.py	Prefer set literals in complex-data fixtures.
tests/_plugins/ui/_impl/tables/test_narwhals.py	Prefer set literals in complex-data fixtures.
tests/_plugins/ui/_impl/dataframes/test_dataframe.py	Simplify boolean-return helper for narwhals detection in tests.
tests/_plugins/ui/_impl/charts/test_altair_transformers.py	Use tuple-form `.startswith((...))` in tests.
tests/_plugins/ui/_core/test_registry.py	Prefer set literals in assertions.
tests/_plugins/stateless/test_image.py	Iterate registry dict directly instead of `.keys()` in tests.
tests/_plugins/stateless/test_image_compare.py	Iterate registry dict directly instead of `.keys()` in tests.
tests/_plugins/stateless/test_audio.py	Iterate registry dict directly instead of `.keys()` in tests.
tests/_plugins/core/test_json_encoder.py	Prefer set literals in set-encoding tests.
tests/_output/test_try_format.py	Prefer set literal in formatting test.
tests/_output/formatters/test_sympy.py	Rename unused symbol bindings to `_y/_z` in tests.
tests/_output/formatters/test_structures.py	Rename unused `data` binding to `_data`; prefer `()` literal in tests.
tests/_output/formatters/test_ibis_formatters.py	Prefer dict literal over `dict(...)` in ibis schema construction tests.
tests/_messaging/test_variables.py	Prefer `()` literal over `tuple()` in tests.
tests/_lint/test_validate_graph.py	Prefer set literals in assertions.
tests/_data/mocks.py	Simplify boolean-return helper in test mock generation.
tests/_ast/test_visitor.py	Prefer literals and simplify string building in tests.
tests/_ast/test_compiler.py	Prefer set literals; avoid `list(...)[0]` by using `next(iter(...))` in tests.
tests/_ast/test_codegen.py	Simplify string assembly; prefer tuple literals.
tests/_ast/test_cell.py	Prefer set literal in assertions.
tests/_ai/llm/test_impl.py	Rename unused mock client bindings in tests.
pyproject.toml	Remove several Ruff ignores now that violations are fixed; keep Ruff scope/excludes intact.
marimo/_utils/site_packages.py	Use tuple-form `.endswith((...))`; simplify boolean return.
marimo/_utils/narwhals_utils.py	Use tuple-form `isinstance(..., (...))` for narwhals type checks.
marimo/_utils/inline_script_metadata.py	Simplify suffix checks; consolidate dependency-prefix matching with tuple `.startswith`.
marimo/_utils/format_signature.py	Use tuple-form `.startswith((...))`.
marimo/_utils/distributor.py	Fix Protocol/Generic base ordering for typing correctness.
marimo/_utils/dataclass_to_openapi.py	Reorder docstring sections to match conventions.
marimo/_utils/async_path.py	Use `Self` return annotation (with postponed evaluation) for `__new__`.
marimo/_sql/utils.py	Use tuple-form `.startswith((...))` for comment detection.
marimo/_snippets/snippets.py	Use tuple-form `.startswith((...))`.
marimo/_session/state/session_view.py	Prefer set comprehension literal over `set([...])`.
marimo/_session/state/serialize.py	Simplify boolean-return logic in cache-hit check.
marimo/_server/utils.py	Remove unused re-export-style import.
marimo/_server/export/_live_notebook_server.py	Use `Self` in `__enter__` return annotation.
marimo/_server/export/_html_asset_server.py	Use `Self` in `__enter__` return annotation.
marimo/_server/errors.py	Simplify accept-header check to direct boolean return.
marimo/_server/api/middleware.py	Replace `raise e` with bare `raise`; simplify redundant exception handling.
marimo/_server/api/endpoints/ws/ws_message_loop.py	Replace `raise e` with bare `raise` to preserve traceback.
marimo/_server/ai/providers.py	Simplify boolean logic in reasoning-model detection.
marimo/_server/ai/mcp/client.py	Iterate dict directly instead of `.keys()`; simplify list comprehension over dict.
marimo/_server/ai/mcp/init.py	Reorder `__all__` entries without functional change.
marimo/_server/ai/ids.py	Use tuple-form `.startswith((...))` for provider inference.
marimo/_save/stores/redis.py	Simplify boolean return for `put`.
marimo/_save/save.py	Prefer set comprehension literal; replace `raise e` with bare `raise`.
marimo/_save/loaders/loader.py	Simplify string construction for error message.
marimo/_save/hash.py	Use `discard` for set removal; prefer set comprehension literal.
marimo/_save/cache.py	Prefer set comprehensions for set conversion/restore paths.
marimo/_runtime/watch/_directory.py	Prefer set comprehension literal over `set(generator)`.
marimo/_runtime/virtual_file/storage.py	Use `Self` return annotation for singleton `__new__`.
marimo/_runtime/virtual_file/init.py	Reorder `__all__` entries without functional change.
marimo/_runtime/runtime.py	Prefer `()` empty tuple; prefer `.get` over membership+index; simplify boolean fields and loops.
marimo/_runtime/runner/hooks_post_execution.py	Prefer set comprehension literal; simplify `.get` usage.
marimo/_runtime/runner/cell_runner.py	Simplify traceback decision; prefer set literal/comprehension; simplify dict `.get`.
marimo/_runtime/reload/module_watcher.py	Prefer set comprehensions and direct dict iteration.
marimo/_runtime/reload/autoreload.py	Iterate dict directly instead of `.keys()`.
marimo/_runtime/primitives.py	Prefer set literal and generator `any(...)` forms.
marimo/_runtime/patches.py	Avoid list allocation inside `min(...)`.
marimo/_runtime/packages/utils.py	Use tuple-form `.endswith((...))` in parser.
marimo/_runtime/packages/pypi_package_manager.py	Use tuple-form `.startswith((...))`; simplify boolean returns and suffix checks.
marimo/_runtime/packages/module_registry.py	Prefer set comprehension literals; simplify expression in `missing_modules`.
marimo/_runtime/functions.py	Replace `raise e` with bare `raise` to preserve traceback.
marimo/_runtime/dataflow/runner.py	Prefer set comprehension literal over `set([...])`.
marimo/_runtime/dataflow/init.py	Prefer set comprehensions for induced subgraphs and edges.
marimo/_runtime/copy.py	Prefer set literal for slot filtering; use `Self` return annotation.
marimo/_runtime/complete.py	Simplify boolean flow; minor idiom cleanups; simplify set subtraction expression.
marimo/_runtime/commands.py	Prefer `request.get(...)` over membership checks.
marimo/_runtime/app/script_runner.py	Prefer set comprehension; replace `raise e` with bare `raise`.
marimo/_plugins/ui/_impl/utils/dataframe.py	Reorder docstring sections to match conventions.
marimo/_plugins/ui/_impl/tabs.py	Prefer list comprehension over `list(generator)`.
marimo/_plugins/ui/_impl/tables/pandas_table.py	Use tuple-form `.startswith((...))` for dtype checks.
marimo/_plugins/ui/_impl/tables/narwhals_table.py	Iterate dict directly instead of `.keys()`.
marimo/_plugins/ui/_impl/tables/default_table.py	Iterate dict directly instead of `.keys()`.
marimo/_plugins/ui/_impl/table.py	Use tuple-form `isinstance(..., (...))`; simplify list comprehension filtering.
marimo/_plugins/ui/_impl/run_button.py	Add noqa for Ruff SIM103 expectation on sentinel check.
marimo/_plugins/ui/_impl/plotly.py	Simplify boolean return logic.
marimo/_plugins/ui/_impl/file_browser.py	Avoid unnecessary `list(...)` around iterator.
marimo/_plugins/ui/_impl/data_explorer.py	Prefer dict literal over `dict(...)` for spec construction.
marimo/_plugins/ui/_impl/data_editor.py	Iterate dict directly instead of `.keys()` for row operations.
marimo/_plugins/stateless/nav_menu.py	Use tuple-form `.startswith((...))` for href validation.
marimo/_plugins/stateless/image.py	Use tuple-form `isinstance(..., (...))` for IO types.
marimo/_plugins/stateless/image_compare.py	Use tuple-form `isinstance(..., (...))` for IO types.
marimo/_plugins/stateless/accordion.py	Prefer list comprehension over `list(generator)`.
marimo/_output/formatters/structures.py	Prefer `()` literal over `tuple()` for formatter identity check.
marimo/_messaging/msgspec_encoder.py	Avoid unnecessary list allocations in list conversions.
marimo/_messaging/console_output_worker.py	Prefer `.get` over membership+index in dict access.
marimo/_lint/validate_graph.py	Avoid unnecessary `list(set(...))` allocation before sorting; prefer set literal operations.
marimo/_lint/rules/runtime/branch_expression.py	Simplify boolean branches to direct comparisons.
marimo/_lint/rules/formatting/markdown_dedent.py	Avoid list allocation inside `any(...)`; use generator form.
marimo/_lint/rule_engine.py	Simplify boolean return; rename unused pending set to `_pending`.
marimo/_dependencies/dependencies.py	Minor lint-driven cleanup in dependency declarations.
marimo/_data/get_datasets.py	Use tuple-form `.startswith((...))` and simplify nested-type checks.
marimo/_convert/markdown/to_ir.py	Simplify string construction for formatted blocks.
marimo/_convert/ipynb/to_ir.py	Use tuple-form `.startswith((...))`; simplify boolean returns.
marimo/_convert/ipynb/init.py	Reorder `__all__` entries without functional change.
marimo/_convert/common/init.py	Reorder `__all__` entries without functional change.
marimo/_code_mode/_context.py	Use `Self` for async context manager enter return type.
marimo/_cli/files/file_path.py	Simplify boolean returns; reorder docstring sections.
marimo/_ast/visitor.py	Prefer set comprehension literal over `set([...])`.
marimo/_ast/toplevel.py	Prefer set comprehension literal over `set([...])`.
marimo/_ast/scanner.py	Use tuple-form `.startswith((...))` for return stripping checks.
marimo/_ast/codegen.py	Prefer `()` literal for empty tuples; simplify string joins and boolean returns.
marimo/_ast/cell.py	Prefer set comprehension literal; simplify comparisons and `next(iter(...))` usage.
marimo/_ast/cell_manager.py	Iterate dict directly instead of `.keys()`.
marimo/_ast/app.py	Rename unused `_linter` binding from helper call.
marimo/_ai/_tools/base.py	Fix ABC/Generic base ordering for typing correctness.
marimo/init.py	Reorder `__all__` exports (no functional change expected).

Copilot

Pull request overview

Copilot reviewed 132 out of 132 changed files in this pull request and generated no new comments.

mscolnick · 2026-04-10T18:26:11Z

    pytest = Dependency("pytest")
    vegafusion = Dependency("vegafusion")
    vl_convert_python = Dependency("vl_convert")
-    dotenv = Dependency("dotenv")


we need this no?

Light2Dark · 2026-04-10T18:27:58Z

    pandas = Dependency("pandas")
    polars = Dependency("polars")
    ibis = Dependency("ibis")
    dotenv = Dependency("dotenv")


it's a duplicate @mscolnick . Cool that ruff picked it up

mscolnick · 2026-04-10T18:39:56Z

merging now to avoid conflicts

Light2Dark added 9 commits April 11, 2026 01:13

remove docstring rule

e1d2df1

remove set rule

a514205

remove join rule

8b15762

remove set and list rules

56deb77

optional none

cfb2908

remove unecc rules

83b1c55

remove more unecc rules

8f4a2d8

correct logic

319d099

remove rules with autofixes

0d4b834

vercel Bot deployed to Preview April 10, 2026 17:27 View deployment

Light2Dark requested a review from Copilot April 10, 2026 17:27

Light2Dark added the internal A refactor or improvement that is not user facing label Apr 10, 2026

Copilot started reviewing on behalf of Light2Dark April 10, 2026 17:28 View session

Copilot AI reviewed Apr 10, 2026

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Light2Dark added 2 commits April 11, 2026 01:34

operator fix

b5a5fb7

fix types

742a0c3

vercel Bot deployed to Preview April 10, 2026 17:35 View deployment

add ignores for intentional avoidance of rules

1f4c8b3

vercel Bot deployed to Preview April 10, 2026 17:56 View deployment

add back rule for unused var

979c2da

vercel Bot deployed to Preview April 10, 2026 18:05 View deployment

Light2Dark requested a review from Copilot April 10, 2026 18:15

Copilot started reviewing on behalf of Light2Dark April 10, 2026 18:15 View session

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Light2Dark marked this pull request as ready for review April 10, 2026 18:20

Light2Dark requested review from akshayka and dmadisetti as code owners April 10, 2026 18:20

Light2Dark requested review from kirangadhave and removed request for akshayka April 10, 2026 18:20

mscolnick reviewed Apr 10, 2026

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Light2Dark commented Apr 10, 2026

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mscolnick approved these changes Apr 10, 2026

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mscolnick merged commit 0c319d2 into main Apr 10, 2026
52 of 54 checks passed

mscolnick deleted the sham/additional-ruff-fixes branch April 10, 2026 18:40

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additional ruff fixes#9132

additional ruff fixes#9132
mscolnick merged 13 commits into
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sham/additional-ruff-fixes

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