Support circular inheritance

src/analyze/stages/flavor/visit-inheritance.ts

@@ -1,17 +1,26 @@
 import { Node } from "typescript";
-import { InheritanceTreeClause, InheritanceTreeNode } from "../../types/inheritance-tree";
 import { AnalyzerVisitContext } from "../../analyzer-visit-context";
+import { InheritanceTreeClause, InheritanceTreeNode } from "../../types/inheritance-tree";
 import { executeFunctionsUntilMatch } from "../../util/execute-functions-until-match";
 
-export function visitAndExpandInheritClause(inheritClause: InheritanceTreeClause, context: AnalyzerVisitContext): InheritanceTreeClause {
+export function visitAndExpandInheritClause(
+	inheritClause: InheritanceTreeClause,
+	context: AnalyzerVisitContext,
+	visitSet: Set<Node>
+): InheritanceTreeClause {
 	const resolved = (() => {
 		if (inheritClause.resolved == null) return undefined;
 
 		return inheritClause.resolved.map(resolved => {
 			let inheritance: InheritanceTreeClause[] = [];
-			visitInheritance(resolved.node, context, results => {
-				inheritance = inheritance.concat(results);
-			});
+			visitInheritance(
+				resolved.node,
+				context,
+				results => {
+					inheritance = inheritance.concat(results);
+				},
+				visitSet
+			);
 
 			return {
 				...resolved,
@@ -22,22 +31,30 @@ export function visitAndExpandInheritClause(inheritClause: InheritanceTreeClause
 
 	return {
 		...inheritClause,
-		horizontalInherits: inheritClause.horizontalInherits?.map(arg => visitAndExpandInheritClause(arg, context)),
+		horizontalInherits: inheritClause.horizontalInherits?.map(arg => visitAndExpandInheritClause(arg, context, visitSet)),
 		resolved
 	};
 }
 
-export function visitInheritance(node: Node, context: AnalyzerVisitContext, emit: (results: InheritanceTreeClause[]) => void): void {
+export function visitInheritance(
+	node: Node,
+	context: AnalyzerVisitContext,
+	emit: (results: InheritanceTreeClause[]) => void,
+	visitSet?: Set<Node>
+): void {
+	visitSet = visitSet || new Set();
+
+	if (visitSet.has(node)) {
+		return;
+	}
+
+	visitSet.add(node);
+
 	const result = executeFunctionsUntilMatch(context.flavors, "discoverInheritance", node, context);
 
 	if (result != null) {
-		emit(result.value.map(link => visitAndExpandInheritClause(link, context)));
+		emit(result.value.map(link => visitAndExpandInheritClause(link, context, visitSet!)));
 
 		if (!result.shouldContinue) return;
 	}
-
-	// Visit child nodes
-	/*node.forEachChild(child => {
-	 visitInheritance2(child, context, emit);
-	 });*/
 }

test/flavors/custom-element/mixin-test.ts

@@ -2,6 +2,55 @@ import test from "ava";
 import { analyzeText } from "../../../src/analyze/analyze-text";
 import { getAttributeNames, getComponentProp, getPropertyNames } from "../../helpers/util";
 
+test("Handles circular inheritance", t => {
+	const { result } = analyzeText(`
+		class MyElement extends MyElement {
+		}
+		
+		/**
+		 * @element
+		 */
+		class MyElement extends MyBase {
+			static get observedAttributes() {
+				return ["a", "b"];
+			}
+		}
+	 `);
+
+	const { members } = result.componentDefinitions[0]?.declaration();
+
+	const attributeNames = getAttributeNames(members);
+
+	t.deepEqual(attributeNames, ["a", "b"]);
+});
+
+test("Handles circular inheritance using mixins", t => {
+	const { result } = analyzeText(`
+		const Mixin1 = (Base) => {
+			return class Mixin1 extends Mixin2(Base) {}
+		}
+		
+		const Mixin2 = (Base) => {
+			return class Mixin2 extends Mixin1(Base) {}
+		}
+		
+		/**
+		 * @element
+		 */
+		class MyElement extends Mixin1(Mixin2(HTMLElement)) {
+			static get observedAttributes() {
+				return ["a", "b"];
+			}
+		}
+	 `);
+
+	const { members } = result.componentDefinitions[0]?.declaration();
+
+	const attributeNames = getAttributeNames(members);
+
+	t.deepEqual(attributeNames, ["a", "b"]);
+});
+
 test("Handles simple mixin", t => {
 	const { result } = analyzeText(`
 		const MyMixin = (Base) => {