TypeScript 3.7 — LanguageService.getEmitOutput returns an empty result

[mjbvz]

TypeScript version: 3.7.0-dev.20191010

We're trying to build VS Code using TS 3.7. As part of this, we use TypeScript LanguageService.getEmitOutput method to request the emitted d.ts of various files: https://github.com/microsoft/vscode/blob/363b9769412fea0d9aef07fa1801371c14d72741/build/monaco/api.ts#L619

WIth TS 3.6, getEmitOutputends up returning a result. However with TS 3.7, it returns an empty array starting on one file: vs/editor/common/standalone/standaloneBase

/cc @DanielRosenwasser

[mjbvz]

A few other observations:

• getEmitOutput does work correctly for a few files before failing on standaloneBase
• If I set emitOnlyDtsFiles to false, I do see the js file being output for standaloneBase but not a d.ts file

[sheetalkamat]

Your tsconfig doesn't have "declaration" enabled and hence its not generating it. 11fd654 changed the way emitOnlyDts works because I had mixed forcing d.ts emit to be always generated with API emitOnlyDts and that could be why you see it. Currently forceDts is internal but do you mind making that method as any and passing that as true to see if that resolves the issue?

[mjbvz]

Thanks. If I monkey patch the TS source to set forceDts to true, It does seem to work. I can't figure out how to enable forceDts from our code however