Allow `@forward` multiple times without `with ()`

[KaelWD]

Reference: https://github.com/vuetifyjs/vuetify/issues/14446

// main.scss
@use 'library' with (
  $var: 'value',
);

// library.scss
@forward 'component-a';
@forward 'component-b';

// component-a.scss
@forward './variables';

// component-b.scss
@forward './variables';

// _variables.scss
$var: 'default' !default;

with is only used in main.scss, so the second forward can just be ignored instead of throwing

Error: This module was already loaded, so it can't be configured using "with".
  ┌──> component-b.scss
1 │   @forward './variables'
  │   ^^^^^^^^^^^^^^^^^^^^^^ new load
  ╵
  ┌──> component-a.scss
1 │   @forward './variables'
  │   ━━━━━━━━━━━━━━━━━━━━━━ original load
  ╵
  ┌──> main.scss
1 │ ┌ @use 'library' with (
2 │ │   $var: 'value',
3 │ │ );
  │ └─^ configuration
  ╵
  component-b.scss 1:1  @forward
  library.scss 2:1      @use
  main.scss 1:1         root stylesheet

[nex3]

I can't reproduce this. What version of Sass are you using?

[Goodwine]

If this is from vuetify, they seem to be using 1.32.13, I did a quick test and found that this exact code sample does indeed fail at that 1-year-old version and it actually fails for 1.33.0 too.

However this code snippet does not fail anymore from 1.34.0 onwards

[KaelWD]

We're only using the new module system in v3 (next branch), v2 is stuck on sass 1.32 because the division changes aren't compatible with the way consumers were overriding variables (@import in prependData).

Here's a minimal reproduction of it with sass 1.52.3 and no other libraries: https://github.com/KaelWD/sass-forward-twice Seems to require the second variable that isn't defined in the first file, if you comment out main.scss:3 and _index.scss:4-5 it doesn't error. Trying to override a non-existent variable with this setup also throws This module was already loaded instead of the expected This variable was not declared with !default in the @used module

[Goodwine]

I can repro, in this case I don't even need the tabs directory and it triggers with just the list directory if you have >=2 variables but not with just one 🤔

[Goodwine]

After debugging and discussing with @nex3 we found this behavior to be "working as specified" but we agreed the desired behavior from this usecase is correct and we'll first need to change the spec, and then implement the fix

I'll mark this as blocked for now until that change in spec happens

[Goodwine]

blocked on

• https://github.com/sass/sass/pull/3357

[Goodwine]

@KaelWD this should fix it, at least on your provided repro repo it does https://github.com/sass/dart-sass/pull/1739

It's still pending the spec changes being merged before we can make this change, but not sure if this would ultimately work for your real-world use-case, I think it should tho 🤔

(I verified with:

• clone dart-sass
• in dart-sass dart pub get && dart run grinder before-test
• update package.json to "sass": "file:/path/to/dart-sass/build/npm" in your project
• in your project npm install && npm run build

) If you want to test feel free and you can let me know if you have any problems 🙂