Pull Request Overview

This PR fixes handling of conditional exports when they map to null values by disabling fallback resolution behavior. The fix prevents TypeScript from continuing to search for modules when a package explicitly maps an export to null, which indicates the export is intentionally disabled.

Key changes:

• Modified module resolution logic to respect null export mappings and stop fallback attempts
• Updated tracing behavior to only log "Resolved under condition" when a non-null value is found
• Added comprehensive test coverage for various module resolution strategies

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

File	Description
tests/cases/conformance/moduleResolution/conditionalExportsResolutionFallbackNull.ts	Test case demonstrating the fix with a package that maps "import" to null
tests/baselines/reference/*.trace.json	Expected trace outputs showing module resolution stops at null mapping
tests/baselines/reference/*.errors.txt	Expected error outputs confirming module not found
src/compiler/moduleNameResolver.ts	Core fix to prevent fallback resolution on null mappings