iitm-circular-reexports.diff

diff --git a/lib/get-exports.js b/lib/get-exports.js
index 70324db..13961ab 100644
--- a/lib/get-exports.js
+++ b/lib/get-exports.js
@@ -9,18 +9,28 @@ function addDefault(arr) {
   return Array.from(new Set(['default', ...arr]))
 }
 
+const urlsBeingProcessed = new Set(); // Guard against circular imports.
+
 async function getFullCjsExports(url, context, parentLoad, source) {
+  if (urlsBeingProcessed.has(url)) {
+    return [];
+  }
+  urlsBeingProcessed.add(url);
+
   const ex = getCjsExports(source)
-  return Array.from(new Set([
+  const full = Array.from(new Set([
     ...addDefault(ex.exports),
     ...(await Promise.all(ex.reexports.map(re => getExports(
-	    re.startsWith('./') || re.startsWith('../')
-	    	? pathToFileURL(require.resolve(fileURLToPath(new URL(re, url)))).toString()
-	    	: pathToFileURL(require.resolve(re)).toString(),
-	    context,
-	    parentLoad
+      re.startsWith('./') || re.startsWith('../')
+        ? pathToFileURL(require.resolve(fileURLToPath(new URL(re, url)))).toString()
+        : pathToFileURL(require.resolve(re)).toString(),
+      context,
+      parentLoad
     )))).flat()
   ]))
+
+  urlsBeingProcessed.delete(url);
+  return full
 }
 
 async function getExports (url, context, parentLoad) {
diff --git a/test/fixtures/circular-a.js b/test/fixtures/circular-a.js
new file mode 100644
index 0000000..f267ad5
--- /dev/null
+++ b/test/fixtures/circular-a.js
@@ -0,0 +1,18 @@
+// The following is generated by tslib. __exportStar is a format which cjs-module-lexer exposes as a reexport
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+  if (k2 === undefined) k2 = k;
+  Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
+}) : (function(o, m, k, k2) {
+  if (k2 === undefined) k2 = k;
+  o[k2] = m[k];
+}));
+var __exportStar = (this && this.__exportStar) || function(m, exports) {
+  for (var p in m) if (p !== "default" && !Object.prototype.hasOwnProperty.call(exports, p)) __createBinding(exports, m, p);
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+
+
+__exportStar(require("./circular-b"), exports);
+
+exports.foo = 42;
+
diff --git a/test/fixtures/circular-b.js b/test/fixtures/circular-b.js
new file mode 100644
index 0000000..597816d
--- /dev/null
+++ b/test/fixtures/circular-b.js
@@ -0,0 +1,15 @@
+// The following is generated by tslib. __exportStar is a format which cjs-module-lexer exposes as a reexport
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+  if (k2 === undefined) k2 = k;
+  Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
+}) : (function(o, m, k, k2) {
+  if (k2 === undefined) k2 = k;
+  o[k2] = m[k];
+}));
+var __exportStar = (this && this.__exportStar) || function(m, exports) {
+  for (var p in m) if (p !== "default" && !Object.prototype.hasOwnProperty.call(exports, p)) __createBinding(exports, m, p);
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+
+__exportStar(require("./circular-a"), exports);
+
diff --git a/test/hook/circular-imports.mjs b/test/hook/circular-imports.mjs
new file mode 100644
index 0000000..3a6a316
--- /dev/null
+++ b/test/hook/circular-imports.mjs
@@ -0,0 +1,11 @@
+import {foo} from '../fixtures/circular-b.js';
+import Hook from '../../index.js'
+import { strictEqual } from 'assert'
+
+Hook((exports, name) => {
+  if (name.match(/circular-[ab].js/)) {
+    exports.foo += 15
+  }
+})
+
+strictEqual(foo, 57);