Fix external helper crash after module-status updates (TDD rewrite)#4022
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RyanCavanaugh wants to merge 2 commits into
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Fix external helper crash after module-status updates (TDD rewrite)#4022RyanCavanaugh wants to merge 2 commits into
RyanCavanaugh wants to merge 2 commits into
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Add a fourslash test that reproduces the panic in checkExternalEmitHelpers when a file transitions from script to decorated exported module. The test edits a file to add @dec and export keywords, then requests diagnostics which triggers the nil pointer dereference in resolveExternalModule. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
checkExternalEmitHelpers could panic after an incremental program update when a file changed from script to module. The reused program state could lack the synthetic tslib import specifier needed for helper resolution. Treat changes to ExternalModuleIndicator or CommonJSModuleIndicator as non-reusable in canReplaceFileInProgram. This forces rebuilt module- resolution state when helper imports may need to be synthesized. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Fixes #3878
Rewrite of #3994
Analysis
\checkExternalEmitHelpers\ panics with a nil pointer dereference in \
esolveExternalModule\ (via \IsStringLiteralLike\) after an incremental program update when a file transitions from script to module. The root cause is that \canReplaceFileInProgram\ allows file reuse even when the module indicator status has changed. When a file becomes a module (e.g. by adding \�xport\), the reused program state lacks the synthetic \ slib\ import specifier needed for helper resolution, causing the nil dereference.
Fix
Add checks in \canReplaceFileInProgram\ to compare \ExternalModuleIndicator\ and \CommonJSModuleIndicator\ between old and new file versions. When either changes (nil to non-nil or vice versa), the file cannot be reused and module-resolution state is rebuilt with the correct synthetic imports.
Copilot Checklist
I successfully ran these commands at the end of my session, and they completed without error: