Add and use clone method for ReadOnlyEnv

mbg · Jul 17, 2026 · Jun 23, 2026 · Jul 13, 2026 · Jul 13, 2026 · Jul 8, 2026
commit b946565527528c534f210541ae538484e228a3ce
@@ -265,6 +265,11 @@ export function getOptionalEnvVar(paramName: string): string | undefined {
 export class ReadOnlyEnv<T extends string | undefined = string | undefined> {
   constructor(protected readonly vars: Record<string, T>) {}
 
+  /** Clones the object while detaching the underlying environment from the original. */
+  public clone(): this {
+    return Object.create(this, { vars: { value: { ...this.vars } } }) as this;
+  }
+
   /** Tries to get the value for `name` and throws if there isn't one. */
   public getRequired(name: string): string {
     return getRequiredEnvVar(this.vars, name);

@@ -240,7 +240,7 @@ abstract class BaseEnvBuilder<
       cloneFrom !== undefined
         ? ({
             ...cloneFrom.state,
-            env: Object.create(cloneFrom.state.env),
+            env: cloneFrom.state.env.clone(),
             actions: Object.create(cloneFrom.state.actions),
             logger: this.logger,
           } satisfies ActionState<AllState>)