[ty] Add version hint for failed stdlib accesses by Gankra · Pull Request #20909 · astral-sh/ruff

Gankra · 2025-10-16T03:00:47Z

This is the ultra-minimal implementation of

distinguish "doesn't exist" from "doesn't exist on this Python version" ty#296

that was previously discussed as a good starting point. In particular we don't actually bother trying to figure out the exact python versions, but we still mention "hey btw for No Reason At All... you're on python 3.10" when you try to access something that has a definition rooted in the stdlib that we believe exists sometimes.

github-actions · 2025-10-16T03:02:50Z

Diagnostic diff on typing conformance tests

No changes detected when running ty on typing conformance tests ✅

github-actions · 2025-10-16T03:04:26Z

`mypy_primer` results

Changes were detected when running on open source projects

scikit-build-core (https://github.com/scikit-build/scikit-build-core)
+ src/scikit_build_core/build/_wheelfile.py:51:22: error[no-matching-overload] No overload of function `field` matches arguments
- Found 51 diagnostics
+ Found 52 diagnostics

No memory usage changes detected ✅

crates/ty/tests/cli/python_environment.rs

...est/snapshots/super.md_-_Super_-_Basic_Usage_-_Explicit_Super_Objec…_(b753048091f275c0).snap

crates/ty_python_semantic/src/types/diagnostic.rs

crates/ty/tests/cli/python_environment.rs

sharkdp · 2025-10-16T07:24:02Z

To be honest, I'm not sure if this initial step is a strict improvement. Sure, it seems helpful in the rare case where you are accessing an attribute that is not available on the Python version that you have configured, but is available under the exact name on a higher version.

But in the vast majority of unresolved-attribute cases (e.g. a misspelled attribute name, or an incomplete attribute name, because I'm still typing it), it just adds additional noise?

"test.exe".trimsuffix(".exe")  # no, it's called "replacesuffix"

error[unresolved-attribute]: Type `Literal["test.exe"]` has no attribute `trimsuffix`
 --> /home/shark/playground/test.py:4:1
  |
4 | "test.exe".trimsuffix(".exe")
  | ^^^^^^^^^^^^^^^^^^^^^
  |
info: Python 3.14 was assumed when accessing `trimsuffix` because it was specified on the command line
info: rule `unresolved-attribute` is enabled by default

Note that the diagnostic change here does not show up in the ecosystem diff because info hints are not part of the concise message, but we have thousands of unresolved-attribute diagnostics across the ecosystem, most of which will be more verbose with this change.

AlexWaygood

Yeah, I agree with @sharkdp that in its current state this could just add a lot of noise and not be that helpful :-(

But I think it's pretty easy to make a few adjustments to this so that it's less noisy, but still pretty useful. Something like this, where we do actually check that the exact symbol exists in the symbol table somewhere (the definition just isn't visible on this Python version), could work pretty well:

diff --git a/crates/ty_python_semantic/src/semantic_index/place.rs b/crates/ty_python_semantic/src/semantic_index/place.rs
index 38e3d92816..75d3eaac65 100644
--- a/crates/ty_python_semantic/src/semantic_index/place.rs
+++ b/crates/ty_python_semantic/src/semantic_index/place.rs
@@ -181,7 +181,6 @@ impl PlaceTable {
     }
 
     /// Looks up a symbol by its name and returns a reference to it, if it exists.
-    #[cfg(test)]
     pub(crate) fn symbol_by_name(&self, name: &str) -> Option<&Symbol> {
         self.symbols.symbol_id(name).map(|id| self.symbol(id))
     }
diff --git a/crates/ty_python_semantic/src/types/diagnostic.rs b/crates/ty_python_semantic/src/types/diagnostic.rs
index f07d934dad..cb6bf8c4e7 100644
--- a/crates/ty_python_semantic/src/types/diagnostic.rs
+++ b/crates/ty_python_semantic/src/types/diagnostic.rs
@@ -9,6 +9,7 @@ use crate::lint::{Level, LintRegistryBuilder, LintStatus};
 use crate::module_resolver::file_to_module;
 use crate::semantic_index::definition::{Definition, DefinitionKind};
 use crate::semantic_index::place::{PlaceTable, ScopedPlaceId};
+use crate::semantic_index::{global_scope, place_table};
 use crate::suppression::FileSuppressionId;
 use crate::types::call::CallError;
 use crate::types::class::{DisjointBase, DisjointBaseKind, Field};
@@ -3155,6 +3156,16 @@ pub(super) fn hint_if_stdlib_attribute_exists_on_other_versions(
     value_type: &Type,
     attr: &Identifier,
 ) {
+    let Type::ModuleLiteral(module) = *value_type else {
+        return;
+    };
+    let Some(file) = module.module(db).file(db) else {
+        return;
+    };
+    let symbol_table = place_table(db, global_scope(db, file));
+    if symbol_table.symbol_by_name(attr).is_none() {
+        return;
+    }
     let Some(definition) = value_type.definition(db) else {
         return;
     };

This edit would mean that the suggestions would only fire on unresolved-attribute errors involving module-literal types. But I think probably most "oops, I tried to access this attribute that only exists on a new Python version" errors involve module-literal objects. So I think even this limited hint would help a lot of users and be a great first step.

Gankra · 2025-10-16T13:22:23Z

Heh, I considered that implementation originally and was like "wait I can do better, and modules are their own definitions so this handles those too!"

Having seen the results, I agree it's a safer minimum.

Gankra · 2025-10-16T13:46:49Z

Pushed up the new implementation.

AlexWaygood

Thank you, this is great!

crates/ty_python_semantic/src/types/diagnostic.rs

…rable * origin/main: [ty] Support dataclass-transform `field_specifiers` (#20888) Bump 0.14.1 (#20925) Standardize syntax error construction (#20903) [`pydoclint`] Implement `docstring-extraneous-parameter` (`DOC102`) (#20376) [ty] Fix panic 'missing root' when handling completion request (#20917) [ty] Run file watching tests serial when using nextest (#20918) [ty] Add version hint for failed stdlib attribute accesses (#20909) More CI improvements (#20920) [ty] Check typeshed VERSIONS for parent modules when reporting failed stdlib imports (#20908)

* main: [ty] Prefer declared type for invariant collection literals (#20927) [ty] Don't track inferability via different `Type` variants (#20677) [ty] Use declared variable types as bidirectional type context (#20796) [ty] Avoid unnecessarily widening generic specializations (#20875) [ty] Support dataclass-transform `field_specifiers` (#20888) Bump 0.14.1 (#20925) Standardize syntax error construction (#20903) [`pydoclint`] Implement `docstring-extraneous-parameter` (`DOC102`) (#20376) [ty] Fix panic 'missing root' when handling completion request (#20917) [ty] Run file watching tests serial when using nextest (#20918) [ty] Add version hint for failed stdlib attribute accesses (#20909) More CI improvements (#20920) [ty] Check typeshed VERSIONS for parent modules when reporting failed stdlib imports (#20908)

…mport a member added on a newer version (#21615) ## Summary Fixes astral-sh/ty#1620. #20909 added hints if you do something like this and your Python version is set to 3.10 or lower: ```py import typing typing.LiteralString ``` And we also have hints if you try to do something like this and your Python version is set too low: ```py from stdlib_module import new_submodule ``` But we don't currently have any subdiagnostic hint if you do something like _this_ and your Python version is set too low: ```py from typing import LiteralString ``` This PR adds that hint! ## Test Plan snapshots --------- Co-authored-by: Aria Desires <[email protected]>

Gankra requested review from AlexWaygood, carljm, dcreager and sharkdp as code owners October 16, 2025 03:00

Gankra added ty Multi-file analysis & type inference diagnostics Related to reporting of diagnostics. labels Oct 16, 2025

Gankra requested a review from MichaReiser as a code owner October 16, 2025 03:09

Gankra commented Oct 16, 2025

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Gankra commented Oct 16, 2025

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MichaReiser approved these changes Oct 16, 2025

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AlexWaygood reviewed Oct 16, 2025

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Gankra force-pushed the gankra/old-python-version branch from 8f49ef0 to d08d591 Compare October 16, 2025 13:10

Gankra changed the base branch from gankra/old-python-version to main October 16, 2025 13:23

Gankra force-pushed the gankra/older-python branch from 0c41f90 to 1198cb2 Compare October 16, 2025 13:46

add version hint for failed stdlib accesses

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Gankra force-pushed the gankra/older-python branch from 1198cb2 to 3079cc3 Compare October 16, 2025 13:48

AlexWaygood approved these changes Oct 16, 2025

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crates/ty_python_semantic/src/types/diagnostic.rs Outdated Show resolved Hide resolved

cleanup comments

752c631

Gankra enabled auto-merge (squash) October 16, 2025 14:03

Gankra merged commit 7155a62 into main Oct 16, 2025
39 of 40 checks passed

Gankra deleted the gankra/older-python branch October 16, 2025 14:07

Gankra mentioned this pull request Oct 16, 2025

distinguish "doesn't exist" from "doesn't exist on this Python version" astral-sh/ty#296

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AlexWaygood mentioned this pull request Nov 24, 2025

[ty] Add hint about resolved Python version when a user attempts to import a member added on a newer version #21615

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[ty] Add version hint for failed stdlib accesses#20909

[ty] Add version hint for failed stdlib accesses#20909
Gankra merged 2 commits intomainfrom
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