Report fatal explicit-home startup failures by youknowdot · Pull Request #9227 · RustPython/RustPython

youknowdot · 2026-10-19T18:18:00Z

Summary

Extract the explicit-PYTHONHOME startup failure closure from the Python 3.15 upgrade:

Retain a failed initial encodings import when an explicit standard-library home was configured.
Before CLI scope/site/user-code execution, print the path configuration and report a fatal startup error with the original exception as its cause. SystemExit(0) and SystemExit(None) from that import cannot turn failed initialization into a successful command.
Preserve the recorded error in worker-VM templates. Default/implicit-path fallback is unchanged; embedding applications can opt into the check. An embedding application explicitly setting a bad home now retains the failure rather than immediately printing the old fallback warning.
Retire the existing canonical test_dump_path_config expected failure after paired verification, using the unchanged updater and preserving all other markers/local adaptations.

Four files; no parser, CAPI error-state, updater, workflow, or new repository test body. Based on main c08375b. Contributor #8732's implicit RUSTPYTHONPATH warning-text work is not duplicated.

Validation

Fresh sqlite+CAPI release at native checkpoint4e089097; final3167502f changes only the verified test marker. Normal hooks and source audits pass.

Historical main58b54 baseline fails the unchanged canonical startup test; candidate and pinned CPython3.15.0 d220409a13b77de7a6c30abe16ea90db01528edc pass. The relevant startup/configuration/test inputs are unchanged between that baseline and this PR's main base.
Private, bounded encodings fixtures raising SystemExit(0/None): baseline exits0 and executes the user command. Candidate and CPython exit1, retain the SystemExit cause, and do not execute the command.
Default startup, -E/-I ignoring invalid home, and valid-home frozen off/on controls pass on all three runtimes. These are behavioral observations, not a claim that every diagnostic byte matches CPython.
Selected canonical test_cmd_line: candidate80 cases (42 passed,23 skipped,15 existing expected failures); oracle80 (68 passed,12 skipped). The existing asyncio-debug case is excluded externally from local execution because it creates an AF_UNIX socketpair; no source skip was added.
Complete canonical test_importlib.frozen:30 passed on both.
Workspace tests: 1,401 passed, 18 ignored. CAPI tests: 123 passed, 4 ignored. Workspace and CAPI strict Clippy passed. All source/protected audits restored clean.

Local validation is Linux. The ordinary embedding constructor remains nonfatal unless its host calls the new check; its no-stdio/fallback behavior was reviewed in source, with existing native/CAPI gates providing their normal coverage rather than a new dedicated embedding fixture. Test data and environment changes were restricted to owned children/private temporary directories. Canonical assertion bodies were not modified.

AI assistance

OpenAI Codex assisted with implementation, independent source review, canonical regeneration, automated validation, and this description under the maintainer's requested Python 3.15 upgrade work. The checks described were automated, not manual human testing. Commits include the assistance trailer; maintainer review is still needed.

Retain explicit standard-library initialization errors for the command-line host, preserving default embedding fallback and the original exception cause. Assisted-by: OpenAI Codex: model version unavailable

Retire the verified expected failure through update_lib, preserving the explicit local path-environment adaptation and all other markers. Assisted-by: OpenAI Codex: model version unavailable

coderabbitai · 2026-10-19T18:29:53Z

Note

Currently processing new changes in this PR. This may take a few minutes, please wait...

⚙️ Run configuration

Configuration used: Repository: RustPython/RustPython/.coderabbit.yml
Review profile: CHILL
Plan: Advanced
Run ID: ad1a40ca-5340-469b-a307-aefb1d39ec32

📥 Commits

Reviewing files that changed from the base of the PR and between c08375b and 3167502.

⛔ Files ignored due to path filters: 1

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

📒 Files selected for processing: 3

crates/vm/src/vm/mod.rs
crates/vm/src/vm/thread.rs
src/lib.rs

+-------------------------------------------------+
| Code Wars Episode II: Attack of the Git Clones. |
+-------------------------------------------------+
  \
   \     /)/)
        ( '')
        /  |
      o(___)

✨ Finishing Touches

🧪 Generate unit tests (beta)

Create a new PR

Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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.}

github-actions · 2026-10-19T19:47:11Z

📦 Library Dependencies

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

:4: SyntaxWarning: invalid decimal literal
:7: SyntaxWarning: "\z" is an invalid escape sequence. Such sequences will not work in the future. Did you mean "\z"? A raw string is also an option.
:10: SyntaxWarning: "\400" is an invalid octal escape sequence. Such sequences will not work in the future. Did you mean "\400"? A raw string is also an option.
:4: SyntaxWarning: invalid decimal literal
:7: SyntaxWarning: "\z" is an invalid escape sequence. Such sequences will not work in the future. Did you mean "\z"? A raw string is also an option.
:10: SyntaxWarning: "\400" is an invalid octal escape sequence. Such sequences will not work in the future. Did you mean "\400"? A raw string is also an option.
:4: SyntaxWarning: invalid decimal literal
:7: SyntaxWarning: "\z" is an invalid escape sequence. Such sequences will not work in the future. Did you mean "\z"? A raw string is also an option.
:10: SyntaxWarning: "\400" is an invalid octal escape sequence. Such sequences will not work in the future. Did you mean "\400"? A raw string is also an option.
[ ] test: cpython/Lib/test/test_cmd_line.py (TODO: 18)

dependencies:

dependent tests: (no tests depend on cmd_line)

Legend:

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

codspeed · 2026-10-19T20:18:41Z

Merging this PR will not alter performance

✅ 62 untouched benchmarks
⏩ 4 skipped benchmarks¹

_{Comparing youknowdot:split/explicit-home-startup-315 (3167502) with main (c08375b)}

4 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

youknowone

this will be useful

chatgpt-codex-connector · 2026-10-20T00:27:32Z

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-20T00:34:05.482828Z	`3167502`	Draft marked ready

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

youknowdot added 2 commits October 20, 2026 02:43

Report fatal explicit-home encodings initialization failures

4e08909

Retain explicit standard-library initialization errors for the command-line host, preserving default embedding fallback and the original exception cause. Assisted-by: OpenAI Codex: model version unavailable

Enable canonical fatal startup path configuration coverage

3167502

Retire the verified expected failure through update_lib, preserving the explicit local path-environment adaptation and all other markers. Assisted-by: OpenAI Codex: model version unavailable

youknowone approved these changes Oct 20, 2026

View reviewed changes

youknowone marked this pull request as ready for review October 20, 2026 00:27

youknowone merged commit 1be1628 into RustPython:main Oct 20, 2026
32 checks passed

Navigation Menu

Repository navigation

Report fatal explicit-home startup failures - #9227

Report fatal explicit-home startup failures#9227
youknowone merged 2 commits into
RustPython:mainfrom
youknowdot:split/explicit-home-startup-315

youknowdot commented Oct 19, 2026

Uh oh!

coderabbitai Bot commented Oct 19, 2026 •

edited

Loading

Uh oh!

github-actions Bot commented Oct 19, 2026

Uh oh!

codspeed Bot commented Oct 19, 2026

Uh oh!

youknowone left a comment

Uh oh!

Uh oh!

chatgpt-codex-connector Bot commented Oct 20, 2026 •

edited

Loading

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Conversation

youknowdot commented Oct 19, 2026

Summary

Validation

AI assistance

Uh oh!

coderabbitai Bot commented Oct 19, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

github-actions Bot commented Oct 19, 2026

📦 Library Dependencies

Uh oh!

codspeed Bot commented Oct 19, 2026

Merging this PR will not alter performance

Footnotes

Uh oh!

youknowone left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

chatgpt-codex-connector Bot commented Oct 20, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codex Review Summary

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

coderabbitai Bot commented Oct 19, 2026 •

edited

Loading

chatgpt-codex-connector Bot commented Oct 20, 2026 •

edited

Loading