fix: completions bug where symbols in first document weren't included

packages/language-services/src/features/__tests__/do-complete-modules.test.ts

@@ -12,7 +12,11 @@ const ls = getLanguageService({ fileSystemProvider, ...rest });
 
 beforeEach(() => {
 	ls.clearCache();
-	ls.configure({}); // Reset any configuration to default
+	ls.configure({
+		completionSettings: {
+			suggestFromUseOnly: true,
+		},
+	}); // Reset any configuration to default
 });
 
 test("suggests built-in sass modules", async () => {
@@ -84,6 +88,62 @@ test("should suggest symbol from a different document via @use", async () => {
 	);
 });
 
+test("should suggest symbols from the document we use when it also forwards another document with symbols", async () => {
+	const one = fileSystemProvider.createDocument("$primary: limegreen;", {
+		uri: "one.scss",
+	});
+	const two = fileSystemProvider.createDocument(
+		['@forward "./one";', "$secondary: red;"],
+		{
+			uri: "two.scss",
+		},
+	);
+	const three = fileSystemProvider.createDocument(
+		['@use "./two";', ".a { color: two."],
+		{
+			uri: "three.scss",
+		},
+	);
+
+	// emulate scanner of language service which adds workspace documents to the cache
+	ls.parseStylesheet(one);
+	ls.parseStylesheet(two);
+	ls.parseStylesheet(three);
+
+	const { items } = await ls.doComplete(three, Position.create(1, 16));
+	assert.notEqual(
+		0,
+		items.length,
+		"Expected to find a completion item for $primary",
+	);
+	assert.deepStrictEqual(
+		items.find((annotation) => annotation.label === "$secondary"),
+		{
+			commitCharacters: [";", ","],
+			documentation: "red\n____\nVariable declared in two.scss",
+			filterText: "two.$secondary",
+			insertText: ".$secondary",
+			kind: CompletionItemKind.Color,
+			label: "$secondary",
+			sortText: undefined,
+			tags: [],
+		},
+	);
+	assert.deepStrictEqual(
+		items.find((annotation) => annotation.label === "$primary"),
+		{
+			commitCharacters: [";", ","],
+			documentation: "limegreen\n____\nVariable declared in one.scss",
+			filterText: "two.$primary",
+			insertText: ".$primary",
+			kind: CompletionItemKind.Color,
+			label: "$primary",
+			sortText: undefined,
+			tags: [],
+		},
+	);
+});
+
 test("should not suggest symbols from a module used by the one we use", async () => {
 	ls.configure({
 		completionSettings: {
@@ -887,6 +947,11 @@ test("given both required and optional parameters should suggest two variants of
 });
 
 test("should suggest all symbols as legacy @import may be in use", async () => {
+	ls.configure({
+		completionSettings: {
+			suggestFromUseOnly: false,
+		},
+	});
 	const one = fileSystemProvider.createDocument("$primary: limegreen;", {
 		uri: "one.scss",
 	});

packages/language-services/src/language-feature.ts

@@ -198,6 +198,14 @@ export abstract class LanguageFeature {
 		}
 
 		let result: T[] = [];
+
+		// gather the results from the initial document if any
+		if (Array.isArray(callbackResult)) {
+			result.push(...callbackResult);
+		} else if (callbackResult) {
+			result.push(callbackResult);
+		}
+
 		for (const link of links) {
 			if (!link.target || link.target === currentDocument.uri) {
 				continue;
@@ -244,7 +252,7 @@ export abstract class LanguageFeature {
 				visited,
 				depth + 1,
 			);
-			result = result.concat(linkResult);
+			result.push(...linkResult);
 		}
 
 		return result;