`FutureFeature` enum by ShaharNaveh · Pull Request #8185 · RustPython/RustPython

ShaharNaveh · 2026-06-28T09:54:53Z

Closes #xxxx
This PR follows our AI policy

Summary

Summary by CodeRabbit

New Features
- More robust handling of from __future__ import ... by reliably recognizing supported feature names.
Bug Fixes
- Invalid future-feature names now produce clearer errors, including the exact location of the problematic import.
- Preserved existing special-case behavior (including braces) and ensured previously-supported flags continue to behave the same.
Refactor
- Centralized future-feature parsing/validation into a consistent internal representation for preprocessing.

coderabbitai · 2026-06-28T09:55:09Z

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: 1f1ae9db-5ae1-4cf7-94d6-2b2502b39ab5

📥 Commits

Reviewing files that changed from the base of the PR and between b68f0e2 and 1bb8fa9.

📒 Files selected for processing (1)

crates/codegen/src/preprocess.rs

🚧 Files skipped from review as they are similar to previous changes (1)

crates/codegen/src/preprocess.rs

📝 Walkthrough

Walkthrough

A shared FutureFeature enum is added for known __future__ names, and compile-time and preprocess-time handling now parse feature strings through it. Unknown names are reported through the new conversion path.

Changes

FutureFeature parsing and preprocessing

Layer / File(s)	Summary
FutureFeature enum and TryFrom `crates/codegen/src/compile.rs`	Defines the public `FutureFeature` enum with variants for known `__future__` feature names and a `TryFrom<&str>` impl returning `Err(name)` for unknown names.
Compile uses FutureFeature `crates/codegen/src/compile.rs`	Converts compile-time future-feature handling from raw string matching to `FutureFeature::try_from()` and enum matching, while preserving the existing handling for recognized features and reporting unknown names with source ranges.
Preprocess uses FutureFeature `crates/codegen/src/preprocess.rs`	Imports `FutureFeature`, parses imported `__future__` names through `try_into()`, maps invalid names and `braces` to the existing preprocess errors, and updates `AstPreprocessor` derives and `visit_astfold_body` ownership.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

A rabbit hops through future flags with glee,
New names are sorted cleanly, one-two-three.
try_into() hums through the warren bright,
And errors land where they should light.
The code now sniffs the future with a grin 🐇

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 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 clearly describes the main addition introduced by the pull request.
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.

✨ Finishing Touches

🧪 Generate unit tests (beta)

Create PR with unit tests

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

_{Comment @coderabbitai help to get the list of available commands.}

coderabbitai

🧹 Nitpick comments (1)

crates/codegen/src/compile.rs (1)
204-287: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Reuse FutureFeature in preprocess.rs as well.

crates/codegen/src/preprocess.rs:196-258 still hardcodes the same __future__ names. Keeping two independent lists means the precheck and codegen paths can drift the next time a feature is added or renamed. Consider moving that path to the enum too so there is a single source of truth.
🤖 Prompt for 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.

In `@crates/codegen/src/compile.rs` around lines 204 - 287, `FutureFeature` is now
the single source of truth for `__future__` names, but `preprocess.rs` still
maintains a separate hardcoded list. Update the `preprocess` path to use
`FutureFeature::try_from` (or otherwise reference `FutureFeature` directly)
instead of duplicating the feature names, so both preprocessing and codegen stay
aligned when `FutureFeature` changes. Keep the existing behavior in the
preprocessing logic, but route name validation/matching through the enum and its
variants rather than a second list.

🤖 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.

Nitpick comments:
In `@crates/codegen/src/compile.rs`:
- Around line 204-287: `FutureFeature` is now the single source of truth for
`__future__` names, but `preprocess.rs` still maintains a separate hardcoded
list. Update the `preprocess` path to use `FutureFeature::try_from` (or
otherwise reference `FutureFeature` directly) instead of duplicating the feature
names, so both preprocessing and codegen stay aligned when `FutureFeature`
changes. Keep the existing behavior in the preprocessing logic, but route name
validation/matching through the enum and its variants rather than a second list.

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yml

Review profile: CHILL

Plan: Pro

Run ID: 86ae9578-dc47-408c-b911-5ebf302e01d2

📥 Commits

Reviewing files that changed from the base of the PR and between 0009dd6 and b7bcf43.

📒 Files selected for processing (1)

crates/codegen/src/compile.rs

coderabbitai Bot reviewed Jun 28, 2026

View reviewed changes

FutureFeature enum

a97f0fe

ShaharNaveh force-pushed the codegen-future-feature-enum branch from b7bcf43 to a97f0fe Compare June 28, 2026 09:57

ShaharNaveh added 2 commits June 28, 2026 14:21

Use it in preprocess as well

b68f0e2

clippy

1bb8fa9

youknowone approved these changes Jun 30, 2026

View reviewed changes

youknowone merged commit eae567f into RustPython:main Jun 30, 2026
26 checks passed

coderabbitai Bot mentioned this pull request Aug 18, 2026

Align compiler futures, annotations, and symtable with CPython #8550

Merged

Navigation Menu

Uh oh!

`FutureFeature` enum - #8185

`FutureFeature` enum#8185
youknowone merged 3 commits into
RustPython:mainfrom
ShaharNaveh:codegen-future-feature-enum

ShaharNaveh commented Jun 28, 2026 •

edited by coderabbitai Bot

Loading

Uh oh!

coderabbitai Bot commented Jun 28, 2026 •

edited

Loading

Walkthrough

Changes

Estimated code review effort

Poem

❌ Failed checks (1 warning)

Uh oh!

coderabbitai Bot left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Uh oh!

Conversation

ShaharNaveh commented Jun 28, 2026 • edited by coderabbitai Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Summary by CodeRabbit

Uh oh!

coderabbitai Bot commented Jun 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Walkthrough

Changes

Estimated code review effort

Poem

❌ Failed checks (1 warning)

Uh oh!

coderabbitai Bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

ShaharNaveh commented Jun 28, 2026 •

edited by coderabbitai Bot

Loading

coderabbitai Bot commented Jun 28, 2026 •

edited

Loading