Cache CompilerOptions.SourceFileAffecting

[jakebailey]

Enabled by #1106, we can now cache the SourceFileAffecting function's results on the CompilerOptions struct itself.

[Copilot]

Pull Request Overview

This PR introduces caching of the SourceFileAffecting result on CompilerOptions (enabled by #1106) and updates call sites and tests accordingly.

• Add sync.Once and a cached field to CompilerOptions and update SourceFileAffecting to initialize once.
• Remove per-Program caching and invoke the cached compiler options directly.
• Update tests in tsconfigparsing_test.go and commandlineparser_test.go to ignore the new unexported fields.
• Remove a stale // TODO comment in fileloader.go.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
internal/tsoptions/tsconfigparsing_test.go	Imported cmpopts and updated DeepEqual to ignore unexported fields
internal/tsoptions/commandlineparser_test.go	Same import and DeepEqual update for command-line parser tests
internal/core/compileroptions.go	Added caching fields and modified SourceFileAffecting to use sync.Once
internal/compiler/program.go	Removed Program-level caching and updated callers to use new cache
internal/compiler/fileloader.go	Removed outdated caching TODO comment

Comments suppressed due to low confidence (3)

internal/core/compileroptions.go:380

• Consider adding tests to verify the caching behavior of SourceFileAffecting, ensuring that repeated calls return the same instance and that concurrency safety holds.

return options.sourceFileAffectingCompilerOptions

internal/core/compileroptions.go:364

• [nitpick] Add a doc comment to explain that SourceFileAffecting caches its result on the CompilerOptions instance, and note any implications if CompilerOptions is mutated afterward.

func (options *CompilerOptions) SourceFileAffecting() *SourceFileAffectingCompilerOptions {

internal/core/compileroptions.go:367

• By caching the SourceFileAffectingCompilerOptions on first call, subsequent calls will not reflect any modifications to CompilerOptions. Consider invalidating or regenerating the cached value if options can change after initialization, or document that options must remain immutable after first use.

options.sourceFileAffectingCompilerOptionsOnce.Do(func() {