sass-loader can't resolve path to _index.scss file when using import alias

[sqal]

• Operating System: Windows 10
• Node Version: 12.2.0
• NPM Version: 6.9.0
• webpack Version: 4.33.0
• sass-loader Version: 7.1.0

Issue

Dart-sass allows us to import an _index.scss or _index.sass file without explicitly adding the _index part at the end of imported file. Currently it only works for relative imports and fails when I try to import _index.scss using an alias in my import path.

Expected Behavior

This code should work

// @/scss is an alias to some-absolute-path/scss and functions/_index.scss exists
@import "~@/scss/functions";

Actual Behavior

Compilation failed

ERROR in ./src/style.scss (./node_modules/css-loader/dist/cjs.js!./node_modules/sass-loader/lib/loader.js??ref--4-2!./src/style.scss)
Module build failed (from ./node_modules/sass-loader/lib/loader.js):

@import "~@/scss/functions";
       ^
      Can't find stylesheet to import.
  ╷
5 │ @import "~@/scss/functions";
  │         ^^^^^^^^^^^^^^^^^^^
  ╵
  stdin 5:9  root stylesheet
      in C:\dev\sass-test\src\style.scss (line 5, column 9)
 @ ./src/style.scss 2:14-130
 @ ./src/index.js

Code

Reproduction https://github.com/sqal/sass-loader-bug-repro

How Do We Reproduce?

• clone my reproduction repositor and try build the project (npm run build)
• also please check my comment in src/style.scss

[alexander-akait]

What you expected? You should use package name, like ~@bootstrap/scss/functions

[sqal]

@evilebottnawi ~@bootstrap/scss/functions ? why bootstrap? I don't use bootstrap. Have you checked my reproduction? I just want to import an _index.scss file e.g. @import "~@/scss/functions" which should resolve to e.g. C:\my-project\packages\scss\functions\_index.scss but it currently doesn't work without adding /_index to the path. I listed all possible options for importing scss file in my reproduction repo (src/syle.scss)

I don't know much about sass-loader source code but propably {request}/_index.{scss,sass} case should be handled here (I could be wrong though :P) https://github.com/webpack-contrib/sass-loader/blob/master/lib/importsToResolve.js#L51 (

// Yup actually adding these paths to the list fixes the issue

`${request}/_index.scss`,
`${request}/_index.sass`,

[imkremen]

@sqal Looks like it's not related to sass-loader.
sass/node-sass#2339

[alexander-akait]

Yes, it is node-sass feature

[sqal]

@evilebottnawi but I don't use node-sass :( I'm using dart-sass implementation and it supports importing _index file since version 1.0.0 https://github.com/sass/dart-sass/blob/master/CHANGELOG.md#100-rc1.

[alexander-akait]

mark as feature, because it is support only sass (dart-sass)