Merge remote-tracking branch 'origin/v4' into v4

package.json

@@ -14,11 +14,12 @@
   "scripts": {
     "build": "rollup -c",
     "dev": "rollup -cw",
+    "test:circular": "cd test/circular && rm -rf output && rollup -c && cd ../..",
     "test:nested": "cd test/nested && rm -rf output && rollup -c && cmp output/output.js expected.js && cmp output/output.css expected.css && cd ../..",
     "test:empty": "cd test/empty && rm -rf output && rollup -c && cmp output/output.js expected.js && cmp output/output.css expected.css && cd ../..",
     "test:simple": "cd test/simple && rm -rf output && rollup -c && cmp output/output.js expected.js && cmp output/output.css expected.css && cd ../..",
     "test:win:simple": "cd .\\test\\simple && del -f output.* && rollup -c && cd .. && ECHO n|comp simple\\output.js expected.js && ECHO n|comp simple\\output.css simple\\expected.css && cd ..",
-    "test": "npm run test:simple && npm run test:nested && npm run test:empty",
+    "test": "npm run test:simple && npm run test:nested && npm run test:empty && npm run test:circular",
     "test:win": "npm run test:win:simple",
     "lint": "prettier rollup.config.js src/**",
     "prepare": "npm run build",

src/index.mjs

@@ -8,13 +8,16 @@ export default function css(options = {}) {
   let fileName = options.fileName
 
   // Get all CSS modules in the order that they were imported
-  const getCSSModules = (id, getModuleInfo, modules = new Set()) => {
-    if (modules.has(id)) {
+  const getCSSModules = (id, getModuleInfo, modules = new Set(), visitedModules = new Set()) => {
+    if (modules.has(id) || visitedModules.has(id)) {
       return new Set()
     }
 
     if (filter(id)) modules.add(id)
 
+    // Prevent infinite recursion with circular dependencies
+    visitedModules.add(id);
+
     // Recursively retrieve all of imported CSS modules
     const info = getModuleInfo(id)
     if (!info) return modules
@@ -23,7 +26,7 @@ export default function css(options = {}) {
       modules = new Set(
         [].concat(
           Array.from(modules),
-          Array.from(getCSSModules(importId, getModuleInfo, modules))
+          Array.from(getCSSModules(importId, getModuleInfo, modules, visitedModules))
         )
       )
     })

test/circular/a.js

@@ -0,0 +1,2 @@
+import b from './b.js';
+export default 42;

test/circular/b.js

@@ -0,0 +1,2 @@
+import a from './a.js';
+export default 42;

test/circular/rollup.config.mjs

@@ -0,0 +1,10 @@
+import css from 'rollup-plugin-css-only'
+
+export default {
+  input: 'a.js',
+  output: {
+    file: 'output/output.js',
+    format: 'esm'
+  },
+  plugins: [css({ output: 'output.css' })]
+}