`builder.getDeclarationDiagnostics` performance regression since 5.6

[alan-agius4]

🔎 Search Terms

Starting with version 5.6, the builder.getDeclarationDiagnostics method has become slower when invoked to retrieve diagnostics for a single SourceFile.

Here are the timing comparisons:

TypeScript Version: 5.5.2

• builder.getDeclarationDiagnostics(): 2.247s
• builder.getDeclarationDiagnostics(builder.getSourceFiles()[0]): 0.19ms
• builder.getSourceFiles().forEach(sf => builder.getDeclarationDiagnostics(sf)): 1.655s

TypeScript Version: 5.7.2

• builder.getDeclarationDiagnostics(): 1.675s
• builder.getDeclarationDiagnostics(builder.getSourceFiles()[0]): 1.791s
• builder.getSourceFiles().forEach(sf => builder.getDeclarationDiagnostics(sf)): 2.824s

🕗 Version & Regression Information

• This changed between versions 5.5 and 5.6
• This changed in commit or PR Show dts errors with --noEmit, fix some of the incremental noEmit issues and support dts diagnostics and fix the caching diagnostics in program #59065

💻 Code

https://github.com/alan-agius4/ts-getDeclarationDiagnostics

🙁 Actual behavior

Regression in performance

🙂 Expected behavior

Similar performance

Additional information about the issue

No response

[alan-agius4]

What is interesting using typeScriptProgram.getDeclarationDiagnostics yields a different outcome

TypeScript Version: 5.5.2
typeScriptProgram.getDeclarationDiagnostics(): 2.237s
typeScriptProgram.getDeclarationDiagnostics(builder.getSourceFiles()[0]): 0.191ms
builder.getSourceFiles().forEach(sf => typeScriptProgram.getDeclarationDiagnostics(sf)): 1.994s

TypeScript Version: 5.7.3
typeScriptProgram.getDeclarationDiagnostics(): 1.664s
typeScriptProgram.getDeclarationDiagnostics(builder.getSourceFiles()[0]): 0.101ms
builder.getSourceFiles().forEach(sf => typeScriptProgram.getDeclarationDiagnostics(sf)): 1.721s