Prevent auto-import crash with automatic JSX runtime

[Copilot]

Auto-import export extraction crashed when checking JSX configured for the automatic runtime because its lightweight aliasResolver left the runtime-specifier hook unimplemented.

• Fix

  • Return no JSX runtime metadata from aliasResolver, matching a compiler program without a recorded runtime import.

• Coverage

  • Add a TSX regression case exercising automatic-runtime JSX inside the reported object-literal and satisfies checking path.

/** @jsxRuntime automatic */
export const x = { value: <div /> } satisfies {};

• Fixes Fatal language server crash during auto-imports #64416

[Daniel Rosenwasser (DanielRosenwasser)]

Copilot is the real module specifier necessary for accurate auto-imports?

[Copilot]

Copilot is the real module specifier necessary for accurate auto-imports?

No—the auto-import registry indexes bound export symbols and resolves their explicit alias chains; it does not use JSX-derived types. The runtime specifier is only needed for JSX namespace/type checking, so omitting it here can affect diagnostics from this lightweight checker but not the exported names, flags, targets, or generated auto-imports.

[Copilot]

Copilot review overview

🟢 Approval recommended

The focused fix matches compiler behavior for absent metadata and directly tests the reported crash path.

Review effort: Balanced
Findings: None

What changed in this PR

Prevents auto-import export extraction from crashing when checking TSX with the automatic JSX runtime.

Changes:

• Return absent JSX runtime metadata from the lightweight alias resolver.
• Add regression coverage for the reported TSX checking path.

File	Description
tsc/​internal/​ls/​autoimport/​aliasresolver.go	Safely handles missing JSX runtime metadata.
tsc/​internal/​ls/​autoimport/​aliasresolver_crash_test.go	Adds automatic-runtime crash regression coverage.

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[Jake Bailey (jakebailey)]

Can we hit this without a targeted unit test? I don't know why we'd need this function present...

[Andrew Branch (andrewbranch)]

Copilot determine the possible paths between the top of the call stack from the issue report and the checker functions actually used by auto-import processing. Try to create a real fourslash test that exercises the failure; GetSemanticDiagnostics() is never called on the auto-import checkers, but we do resolve types in certain cases.

[Andrew Branch (andrewbranch)]

Since it stopped with an error, I wonder if the test actually fails without the fix 🤔

[Copilot]

Copilot determine the possible paths between the top of the call stack from the issue report and the checker functions actually used by auto-import processing. Try to create a real foursl...

Addressed in 5c3daaf (final cleanup a785796). The production path is extractPackage → extractFromFile → tryResolveSymbol → GetAliasedSymbol → export-assignment property-access resolution → inferred container initializer → satisfies/JSX checking. The new fourslash completion test exercises that path through a dependency’s default export; it panics with the old implementation and passes with the fix. npx hereby validate passes.

[Andrew Branch (andrewbranch)]

What does this do?

[Gabriela Araujo Britto (gabritto)]

If you mean f.MarkTestAsStradaServer(), one of the things it does is avoid the usual fourslash behavior of opening every file in the test before running the test (because Strada Server tests didn't have this behavior). We should probably rename it now that we're done with the port.

[Daniel Rosenwasser (DanielRosenwasser)]

Copilot is a package with a types field that directs to a tsx file the best test case? Maybe something (minimal) with project references would be more realistic if you can prove that it actually caused errors previously. Maybe add that as an additional test case to the same file.

[Copilot]

Copilot is a package with a types field that directs to a tsx file the best test case? Maybe something (minimal) with project references would be more realistic if you can prove that it actuall...

Added the project-reference case in 1995e1d. It uses a composite TSX library whose package types output is redirected to source through the app’s project reference and node_modules symlink. I verified this test panics with the old implementation and passes with the fix; npx hereby validate passes.

[Jake Bailey (jakebailey)]

If this is happening on a real TSX/JSX (even JS) file, won't it be bad that this is not here?

[Andrew Branch (andrewbranch)]

Kinda, but not that bad. We only pull on types to get flags that contribute to the little icon in the dropdown list, and it's already an intentional compromise between accuracy and performance. I don't feel bad about stopping the spiraling type resolution here.