Sync upstream Gemini-CLI v0.8.2 (#838)

packages/cli/src/utils/envVarResolver.ts

@@ -0,0 +1,112 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * Resolves environment variables in a string.
+ * Replaces $VAR_NAME and ${VAR_NAME} with their corresponding environment variable values.
+ * If the environment variable is not defined, the original placeholder is preserved.
+ *
+ * @param value - The string that may contain environment variable placeholders
+ * @returns The string with environment variables resolved
+ *
+ * @example
+ * resolveEnvVarsInString("Token: $API_KEY") // Returns "Token: secret-123"
+ * resolveEnvVarsInString("URL: ${BASE_URL}/api") // Returns "URL: https://api.example.com/api"
+ * resolveEnvVarsInString("Missing: $UNDEFINED_VAR") // Returns "Missing: $UNDEFINED_VAR"
+ */
+export function resolveEnvVarsInString(value: string): string {
+  const envVarRegex = /\$(?:(\w+)|{([^}]+)})/g; // Find $VAR_NAME or ${VAR_NAME}
+  return value.replace(envVarRegex, (match, varName1, varName2) => {
+    const varName = varName1 || varName2;
+    if (process && process.env && typeof process.env[varName] === 'string') {
+      return process.env[varName]!;
+    }
+    return match;
+  });
+}
+
+/**
+ * Recursively resolves environment variables in an object of any type.
+ * Handles strings, arrays, nested objects, and preserves other primitive types.
+ * Protected against circular references using a WeakSet to track visited objects.
+ *
+ * @param obj - The object to process for environment variable resolution
+ * @returns A new object with environment variables resolved
+ *
+ * @example
+ * const config = {
+ *   server: {
+ *     host: "$HOST",
+ *     port: "${PORT}",
+ *     enabled: true,
+ *     tags: ["$ENV", "api"]
+ *   }
+ * };
+ * const resolved = resolveEnvVarsInObject(config);
+ */
+export function resolveEnvVarsInObject<T>(obj: T): T {
+  return resolveEnvVarsInObjectInternal(obj, new WeakSet());
+}
+
+/**
+ * Internal implementation of resolveEnvVarsInObject with circular reference protection.
+ *
+ * @param obj - The object to process
+ * @param visited - WeakSet to track visited objects and prevent circular references
+ * @returns A new object with environment variables resolved
+ */
+function resolveEnvVarsInObjectInternal<T>(
+  obj: T,
+  visited: WeakSet<object>,
+): T {
+  if (
+    obj === null ||
+    obj === undefined ||
+    typeof obj === 'boolean' ||
+    typeof obj === 'number'
+  ) {
+    return obj;
+  }
+
+  if (typeof obj === 'string') {
+    return resolveEnvVarsInString(obj) as unknown as T;
+  }
+
+  if (Array.isArray(obj)) {
+    // Check for circular reference
+    if (visited.has(obj)) {
+      // Return a shallow copy to break the cycle
+      return [...obj] as unknown as T;
+    }
+
+    visited.add(obj);
+    const result = obj.map((item) =>
+      resolveEnvVarsInObjectInternal(item, visited),
+    ) as unknown as T;
+    visited.delete(obj);
+    return result;
+  }
+
+  if (typeof obj === 'object') {
+    // Check for circular reference
+    if (visited.has(obj as object)) {
+      // Return a shallow copy to break the cycle
+      return { ...obj } as T;
+    }
+
+    visited.add(obj as object);
+    const newObj = { ...obj } as T;
+    for (const key in newObj) {
+      if (Object.prototype.hasOwnProperty.call(newObj, key)) {
+        newObj[key] = resolveEnvVarsInObjectInternal(newObj[key], visited);
+      }
+    }
+    visited.delete(obj as object);
+    return newObj;
+  }
+
+  return obj;
+}