Apply API recommendations for Create Env API

src/client/pythonEnvironments/creation/createEnvironment.ts

@@ -33,14 +33,12 @@ function fireStartedEvent(options?: CreateEnvironmentOptions): void {
 }
 
 function fireExitedEvent(result?: CreateEnvironmentResult, options?: CreateEnvironmentOptions, error?: Error): void {
-    onCreateEnvironmentExitedEvent.fire({
-        options,
-        workspaceFolder: result?.workspaceFolder,
-        path: result?.path,
-        action: result?.action,
-        error: error || result?.error,
-    });
     startedEventCount -= 1;
+    if (result) {
+        onCreateEnvironmentExitedEvent.fire({ options, ...result });
+    } else if (error) {
+        onCreateEnvironmentExitedEvent.fire({ options, error });
+    }
 }
 
 export function getCreationEvents(): {
@@ -195,5 +193,8 @@ export async function handleCreateEnvironmentCommand(
         }
     }
 
-    return result;
+    if (result) {
+        return Object.freeze(result);
+    }
+    return undefined;
 }

src/client/pythonEnvironments/creation/proposed.createEnvApis.ts

@@ -43,37 +43,80 @@ export interface EnvironmentWillCreateEvent {
     options: CreateEnvironmentOptions | undefined;
 }
 
+export type CreateEnvironmentResult =
+    | {
+          /**
+           * Workspace folder associated with the environment.
+           */
+          readonly workspaceFolder?: WorkspaceFolder;
+
+          /**
+           * Path to the executable python in the environment
+           */
+          readonly path: string;
+
+          /**
+           * User action that resulted in exit from the create environment flow.
+           */
+          readonly action?: CreateEnvironmentUserActions;
+
+          /**
+           * Error if any occurred during environment creation.
+           */
+          readonly error?: Error;
+      }
+    | {
+          /**
+           * Workspace folder associated with the environment.
+           */
+          readonly workspaceFolder?: WorkspaceFolder;
+
+          /**
+           * Path to the executable python in the environment
+           */
+          readonly path?: string;
+
+          /**
+           * User action that resulted in exit from the create environment flow.
+           */
+          readonly action: CreateEnvironmentUserActions;
+
+          /**
+           * Error if any occurred during environment creation.
+           */
+          readonly error?: Error;
+      }
+    | {
+          /**
+           * Workspace folder associated with the environment.
+           */
+          readonly workspaceFolder?: WorkspaceFolder;
+
+          /**
+           * Path to the executable python in the environment
+           */
+          readonly path?: string;
+
+          /**
+           * User action that resulted in exit from the create environment flow.
+           */
+          readonly action?: CreateEnvironmentUserActions;
+
+          /**
+           * Error if any occurred during environment creation.
+           */
+          readonly error: Error;
+      };
+
 /**
  * Params passed on `onDidCreateEnvironment` event handler.
  */
-export interface EnvironmentDidCreateEvent extends CreateEnvironmentResult {
+export type EnvironmentDidCreateEvent = CreateEnvironmentResult & {
     /**
      * Options used to create the Python environment.
      */
     options: CreateEnvironmentOptions | undefined;
-}
-
-export interface CreateEnvironmentResult {
-    /**
-     * Workspace folder associated with the environment.
-     */
-    workspaceFolder: WorkspaceFolder | undefined;
-
-    /**
-     * Path to the executable python in the environment
-     */
-    path: string | undefined;
-
-    /**
-     * User action that resulted in exit from the create environment flow.
-     */
-    action: CreateEnvironmentUserActions | undefined;
-
-    /**
-     * Error if any occurred during environment creation.
-     */
-    error: Error | undefined;
-}
+};
 
 /**
  * Extensions that want to contribute their own environment creation can do that by registering an object