fix(config): avoid recursion when interpolating env (#8014)

packages/config/src/load.js

@@ -153,7 +153,7 @@ function expand (target, source = {}, parse = v => v) {
     return source[key] !== undefined ? source[key] : target[key]
   }
 
-  function interpolate (value) {
+  function interpolate (value, parents = []) {
     if (typeof value !== 'string') {
       return value
     }
@@ -171,10 +171,16 @@ function expand (target, source = {}, parse = v => v) {
         const key = parts[2]
         replacePart = parts[0].substring(prefix.length)
 
+        // Avoid recursion
+        if (parents.includes(key)) {
+          consola.warn(`Please avoid recursive environment variables ( loop: ${parents.join(' > ')} > ${key} )`)
+          return ''
+        }
+
         value = getValue(key)
 
         // Resolve recursive interpolations
-        value = interpolate(value)
+        value = interpolate(value, [...parents, key])
       }
 
       return value !== undefined ? newValue.replace(replacePart, value) : newValue

test/fixtures/runtime-config/.env

@@ -2,4 +2,7 @@ BASE_URL=/api
 PUBLIC_URL=https://google.com
 SERVER_BASE_URL
 API_SECRET=1234
+A=$B
+B=$C
+C=$A
 TOKEN=$2yr$10$tN3JmuvXZKGwi0l38A.SxUVemGrFJiyLunyqkOqOTE7LHsrSwMEmEB

test/fixtures/runtime-config/nuxt.config.js

@@ -6,7 +6,8 @@ export default {
   },
   privateRuntimeConfig: {
     baseURL: '${PUBLIC_URL}${BASE_URL}',
-    API_SECRET: ''
+    API_SECRET: '',
+    FOO: '123/${FOO}'
   },
   serverMiddleware: [
     (req, _, next) => {