fix: Set eyeglass root within a directory-scoped processor.

In a directory scoped processor, we want to treat the root directory
of the processor as the eyeglass root. We override any root setting
that the application's configuration has provided, but we allow the
root to be overridden in the processor's setupOptions() method.

Usually the application's root is good enough for compilation, but there
are situation where the directory structures don't align and it's
important for the scoped processor to have it's root take precendence.
Namely: yarn link'ed development requires this.

Author: chriseppstein

packages/@css-blocks/eyeglass/src/index.ts

@@ -1,9 +1,9 @@
 import type { OptionalPreprocessor, OptionalPreprocessorSync, Preprocessor, PreprocessorSync, ProcessedFile, ResolvedConfiguration } from "@css-blocks/core";
 import type { EyeglassOptions, default as Eyeglass } from "eyeglass"; // works, even tho a cjs export. huh.
+import cloneDeep = require("lodash.clonedeep");
 import type { Result, SassError } from "node-sass";
 import type SassImplementation from "node-sass";
 import { sep as PATH_SEPARATOR } from "path";
-import cloneDeep = require("lodash.clonedeep");
 
 export type Adaptor = (sass: typeof SassImplementation, eyeglass: typeof Eyeglass, options: EyeglassOptions) => Preprocessor;
 export type AdaptorSync = (sass: typeof SassImplementation, eyeglass: typeof Eyeglass, options: EyeglassOptions) => PreprocessorSync;
@@ -123,6 +123,8 @@ export class DirectoryScopedPreprocessor implements PreprocessorProvider {
      * eyeglass.VERSION.
      */
     init(sass: typeof SassImplementation, eyeglass: typeof Eyeglass, options: EyeglassOptions = {}) {
+        options = cloneDeep(options);
+        setEyeglassRoot(options, this.filePrefix);
         let sassOptions = this.setupOptions(options);
 
         let sassOptionsSync = cloneDeep(sassOptions);
@@ -201,6 +203,14 @@ export class DirectoryScopedPreprocessor implements PreprocessorProvider {
     }
 }
 
+function setEyeglassRoot(options: EyeglassOptions, root: string): EyeglassOptions {
+    if (!options.eyeglass) {
+        options.eyeglass = {};
+    }
+    options.eyeglass.root = root;
+    return options;
+}
+
 /**
  * Creates a unified preprocessor for an application to use when consuming
  * css blocks that have Sass preprocessed.

packages/@css-blocks/eyeglass/test/package-test.ts

@@ -141,6 +141,7 @@ describe("@css-blocks/eyeglass", async () => {
 
       /*# sourceMappingURL=two.block.css.map */`));
   });
+
   it("can adapt from several optional adaptors - synchronous", () => {
     let package1Dir = fixture("package-1");
     let package1File = fixture("package-1/one.block.scss");
@@ -172,6 +173,55 @@ describe("@css-blocks/eyeglass", async () => {
 
       /*# sourceMappingURL=two.block.css.map */`));
   });
+
+  it("sets the eyeglass root", async () => {
+    let package1Dir = fixture("package-1");
+    let package1File = fixture("package-1/one.block.scss");
+    let optionsPassedToSetup: EyeglassOptions | undefined;
+    class Adaptor1 extends DirectoryScopedPreprocessor {
+      setupOptions(options: EyeglassOptions): EyeglassOptions {
+        optionsPassedToSetup = options;
+        return Object.assign({}, options, {outputStyle: "compact"});
+      }
+    }
+    let adaptor1 = new Adaptor1(package1Dir);
+    let originalOptions = {
+      eyeglass: {
+        root: process.cwd(),
+      },
+    };
+    let processor = adaptAll([adaptor1], SassImplementation, Eyeglass, originalOptions);
+    await processor(package1File, fs.readFileSync(package1File, "utf-8"), resolveConfiguration({}));
+    assert.equal(optionsPassedToSetup?.eyeglass?.root, package1Dir + "/");
+    assert.equal(originalOptions.eyeglass.root, process.cwd());
+  });
+
+  it("can mutate options without changing the original value", async () => {
+    let package1Dir = fixture("package-1");
+    let package1File = fixture("package-1/one.block.scss");
+    let optionsPassedToSetup: EyeglassOptions | undefined;
+    class Adaptor1 extends DirectoryScopedPreprocessor {
+      setupOptions(options: EyeglassOptions): EyeglassOptions {
+        optionsPassedToSetup = options;
+        options.outputStyle = "compact";
+        return options;
+      }
+      setupOptionsSync(options: EyeglassOptions): EyeglassOptions {
+        options.outputStyle = "expanded";
+        return options;
+      }
+    }
+    let adaptor1 = new Adaptor1(package1Dir);
+    let originalOptions: EyeglassOptions = {
+      eyeglass: {
+        root: process.cwd(),
+      },
+    };
+    let processor = adaptAll([adaptor1], SassImplementation, Eyeglass, originalOptions);
+    await processor(package1File, fs.readFileSync(package1File, "utf-8"), resolveConfiguration({}));
+    assert.isUndefined(originalOptions.outputStyle);
+    assert.equal(optionsPassedToSetup?.outputStyle, "compact");
+  });
 });
 
 function dedent(s: string): string {