Make view result optional

In case it's not managed by a comm

Author: lionel-

positron/comms/variables-backend-openrpc.json

@@ -186,7 +186,8 @@
 				"schema": {
 					"description": "The ID of the viewer that was opened.",
 					"type": "string"
-				}
+				},
+				"required": false
 			}
 		}
 	],

src/vs/workbench/contrib/positronVariables/browser/components/variableItem.tsx

@@ -138,10 +138,10 @@ export const VariableItem = (props: VariableItemProps) => {
 			}
 
 			// If a binding was returned, save the binding between the viewer and the
-			// variable item. Note that we intentionally treat `""` as falsy here so
-			// that backends can return an empty ID if no comm was open. This happens
-			// with Ark when the user views a function object: a virtual document is
-			// opened in an editor but is not managed by a comm.
+			// variable item. Note that it's valid for backends to not return any ID
+			// if no comm was open. This happens with Ark when the user views a
+			// function object: a virtual document is opened in an editor but is not
+			// managed by a comm.
 			if (viewerId) {
 				explorerService.setInstanceForVar(viewerId, item.id);
 			}

src/vs/workbench/services/languageRuntime/common/languageRuntimeVariablesClient.ts

@@ -76,9 +76,9 @@ export class PositronVariable {
 	/**
 	 * Requests that the language runtime open a viewer for this variable.
 	 *
-	 * @returns The ID of the viewer that was opened.
+	 * @returns The ID of the viewer that was opened, if any.
 	 */
-	async view(): Promise<string> {
+	async view(): Promise<string | undefined> {
 		const path = this.parentKeys.concat(this.data.access_key);
 		return this._comm.view(path);
 	}
@@ -268,4 +268,3 @@ export class VariablesClientInstance extends Disposable {
 		}));
 	}
 }
-

src/vs/workbench/services/languageRuntime/common/positronVariablesComm.ts

@@ -415,7 +415,7 @@ export class PositronVariablesComm extends PositronBaseComm {
 	 *
 	 * @returns The ID of the viewer that was opened.
 	 */
-	view(path: Array<string>): Promise<string> {
+	view(path: Array<string>): Promise<string | undefined> {
 		return super.performRpc('view', ['path'], [path]);
 	}
 

src/vs/workbench/services/positronVariables/common/classes/variableItem.ts

@@ -324,7 +324,7 @@ export class VariableItem implements IVariableItem {
 	/**
 	 * Requests that a viewer be opened for this variable.
 	 */
-	async view(): Promise<string> {
+	async view(): Promise<string | undefined> {
 		return this._variable.view();
 	}
 

src/vs/workbench/services/positronVariables/common/interfaces/variableItem.ts

@@ -85,5 +85,5 @@ export interface IVariableItem {
 	/**
 	 * Requests that a data viewer be opened for this variable.
 	 */
-	view(): Promise<string>;
+	view(): Promise<string | undefined>;
 }