docs: document config executing multiple times (#34576)

Author: agg23

docs/src/test-api/class-testproject.md

@@ -183,6 +183,10 @@ Metadata that will be put directly to the test report serialized as JSON.
 
 Project name is visible in the report and during test execution.
 
+:::warning
+Playwright executes the configuration file multiple times. Do not dynamically produce non-stable values in your configuration.
+:::
+
 ## property: TestProject.snapshotDir
 * since: v1.10
 - type: ?<[string]>

packages/playwright/types/test.d.ts

@@ -349,6 +349,10 @@ interface TestProject<TestArgs = {}, WorkerArgs = {}> {
 
   /**
    * Project name is visible in the report and during test execution.
+   *
+   * **NOTE** Playwright executes the configuration file multiple times. Do not dynamically produce non-stable values in
+   * your configuration.
+   *
    */
   name?: string;