[ty] Improve diagnostics when a submodule is not available as an attribute on a module-literal type #21561
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AlexWaygood
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Diagnostic diff on typing conformance testsNo changes detected when running ty on typing conformance tests ✅ |
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| Lint rule | Added | Removed | Changed |
|---|---|---|---|
unresolved-attribute |
0 | 0 | 1,858 |
| Total | 0 | 0 | 1,858 |
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I skimmed the ecosystem results, and couldn't see any false positives where the new diagnostic message was inappropriate. |
carljm
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Nov 21, 2025
crates/ty_python_semantic/resources/mdtest/import/nonstandard_conventions.md
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AlexWaygood
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| let mut diag = builder.into_diagnostic(format_args!( | ||
| "Submodule `{attr_name}` may not be available as an attribute \ | ||
| on module `{module_name}`" | ||
| )); | ||
| diag.help(format_args!( | ||
| "Consider explicitly importing `{maybe_submodule_name}`" | ||
| )); | ||
| return fallback(); |
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if we hit this branch, we have pretty high confidence that we know what the user meant here -- we could even consider inferring the module-literal type of the submodule rather than inferring Unknown. (Or <submodule type> | Unknown...?)
And since this often will (by pure luck!) work at runtime, we could also consider downgrading the diagnostic to warning-level rather than error-level
But either of those would be separate changes from simply improving the diagnostic error message, which is all that this humble PR seeks to achieve.
…ibute on a module-literal type
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* origin/main: (27 commits) [ty] Add hint about resolved Python version when a user attempts to import a member added on a newer version (#21615) Use release commit for actions/checkout (#21610) [ty] Add failing mdtest for known `Protocol` panic (#21594) [`parser`] Fix panic when parsing IPython escape command expressions (#21480) Fix cargo shear in CI (#21609) Update actions/checkout digest to c2d88d3 (#21601) Update dependency ruff to v0.14.6 (#21603) Update astral-sh/setup-uv action to v7.1.4 (#21602) Update Rust crate clap to v4.5.53 (#21604) Update taiki-e/install-action action to v2.62.56 (#21608) Update Rust crate hashbrown to v0.16.1 (#21605) Update Rust crate indexmap to v2.12.1 (#21606) Update Rust crate syn to v2.0.111 (#21607) [ty] Check method definitions on subclasses for Liskov violations (#21436) [ty] Fix panic for unclosed string literal in type annotation position (#21592) [ty] Fix rendering of unused suppression diagnostic (#21580) [ty] Improve lsp handling of hover/goto on imports (#21572) [ty] Improve diagnostics when a submodule is not available as an attribute on a module-literal type (#21561) [ty] Improve concise diagnostics for invalid exceptions when a user catches a tuple of objects (#21578) [ty] upgrade salsa (#21575) ...
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Summary
It's often not obvious to users why we sometimes report
unresolved-attributeerrors for submodules-accessed-on-parent-modules, even though these attributes often are available at runtime (sometimes by sheer luck!). This PR adds a dedicated diagnostic for this case that helps guide the user towards how they can fix the error.Test Plan
Added snapshots