svelte-check --compiler-warnings ignored when tsconfig.json has compilerOptions

[jnikula]

Describe the bug

Upgraded to svelte 5. Started getting:

tsconfig.json:7:3
Error: 'forceConsistentCasingInFileNames' should be set inside the 'compilerOptions' object of the config json file 

Tried to move it to compilerOptions, but simply adding compilerOptions in tsconfig.json apparently makes svelte-check ignore the --compiler-warnings command-line option set in package.json. I get a plethora of warnings that should've been ignored.

Reproduction

Add --compiler-warnings option to svelte-check in package.json to ignore some warning.

Hit that warning.

Add compilerOptions object in tsconfig.json. The object doesn't have to have anything meaningful, simply its presence will make svelte-check ignore the --compiler-warnings option.

Expected behaviour

I'd expect command-line options to amend whatever is in the config file, not to be ignored. The minimum would be a warning about command-line options being incompatible with configuration.

System Info

• OS: Linux
• IDE: Emacs, command-line

Which package is the issue about?

svelte-check

Additional Information, eg. Screenshots

No response

[jnikula]

I tried adding warningFilter in compilerOptions in svelte.config.js, and that can be used to replace the --compiler-warnings command-line option. However, that too gets ignored when I set compilerOptions in tsconfig.json.

I'm pretty much lost on how all these things should be working together. Bottom line, this is blocking my Svelte 5 migration.

[dummdidumm]

Please provide a reproduction repository. I have no idea what the warnings are that are supposed to not show up and what the code is that makes them appear.

[jnikula]

The repo is https://github.com/groovescore/snooker-scoreboard and the reproduction branches there are:

• svelte-5 After migration, npm run check started complaining Error: 'forceConsistentCasingInFileNames' should be set inside the 'compilerOptions' object of the config json file
• svelte-5-compiler-options This is svelte-5 branch plus a simple attempt at moving forceConsistentCasingInFileNames inside compilerOptions. Leads to svelte-check --compiler-warnings being ignored.
• svelte-5-warning-filter This is svelte-5 branch plus first switching from --compiler-warnings to warningFilter, and then the same simple attempt as above. Leads to the warningFilter being ignored.

I just don't know how to both keep the warning ignores/filters I have and fix the new warning introduced during the migration.

[jasonlyu123]

It's not that the --compiler-warnings is ignored when there is compilerOptions in your tsconfig. It's because you encounter two breaking changes from svelte-check and svelte. In svelte-check v4, errors in tsconfig.json will prevent further checks. And in svelte 5, the warning is renamed.

Maybe we could map the --compiler-warnings to its new name or issue a warning when the flag is passed with the old naming scheme, i.e., - instead of _. But because of how the warning filtering works, we can't map the code to the new code for you. You have to use the new names.