Do not execute when terminal is not ready

Author: anthonykim1

src/client/common/terminal/service.ts

@@ -20,9 +20,9 @@ import {
     TerminalShellType,
 } from './types';
 import { traceVerbose } from '../../logging';
+import { sleep } from '../utils/async';
 import { useEnvExtension } from '../../envExt/api.internal';
 import { ensureTerminalLegacy } from '../../envExt/api.legacy';
-import { sleep } from '../utils/async';
 
 @injectable()
 export class TerminalService implements ITerminalService, Disposable {
@@ -81,7 +81,14 @@ export class TerminalService implements ITerminalService, Disposable {
         commandLine: string,
         isPythonShell: boolean,
     ): Promise<TerminalShellExecution | undefined> {
-        const terminal = this.terminal!;
+        // TODO: First execution of shift+enter may get ignored when using sendText.
+        // Prevent Cannot read properties of undefined: https://github.com/microsoft/vscode-python-environments/issues/958
+        if (!this.terminal) {
+            traceVerbose('Terminal not available yet, cannot execute command');
+            return undefined;
+        }
+
+        const terminal = this.terminal;
         if (!this.options?.hideFromUser) {
             terminal.show(true);
         }
@@ -128,6 +135,7 @@ export class TerminalService implements ITerminalService, Disposable {
         }
     }
     // TODO: Debt switch to Promise<Terminal> ---> breaks 20 tests
+    // TODO: Properly migrate all creation, ensureTerminal to environment extension.
     public async ensureTerminal(preserveFocus: boolean = true): Promise<void> {
         if (this.terminal) {
             return;
@@ -138,7 +146,6 @@ export class TerminalService implements ITerminalService, Disposable {
                 name: this.options?.title || 'Python',
                 hideFromUser: this.options?.hideFromUser,
             });
-            // Return early to prevent duplicate creation of terminal when using env extension.
             return;
         } else {
             this.terminalShellType = this.terminalHelper.identifyTerminalShell(this.terminal);