[vscode] Support TerminalState shell property

fixes #15433

Contributed on behalf of STMicroelectronics

Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

Author: rschnekenbu

packages/plugin-ext/src/common/plugin-api-rpc.ts

@@ -312,7 +312,8 @@ export interface TerminalServiceExt {
     $terminalOnInput(id: string, data: string): void;
     $terminalSizeChanged(id: string, cols: number, rows: number): void;
     $currentTerminalChanged(id: string | undefined): void;
-    $terminalStateChanged(id: string): void;
+    $terminalOnInteraction(id: string): void;
+    $terminalShellTypeChanged(id: string, newShellType: string): void;
     $initEnvironmentVariableCollections(collections: [string, string, boolean, SerializableEnvironmentVariableCollection][]): void;
     $provideTerminalLinks(line: string, terminalId: string, token: theia.CancellationToken): Promise<ProvidedTerminalLink[]>;
     $handleTerminalLink(link: ProvidedTerminalLink): Promise<void>;

packages/plugin-ext/src/main/browser/terminal-main.ts

@@ -130,9 +130,12 @@ export class TerminalServiceMainImpl implements TerminalServiceMain, TerminalLin
         }));
         this.toDispose.push(terminal.onData(data => {
             this.extProxy.$terminalOnInput(terminal.id, data);
-            this.extProxy.$terminalStateChanged(terminal.id);
+            this.extProxy.$terminalOnInteraction(terminal.id);
         }));
 
+        this.toDispose.push(terminal.onShellTypeChanged(shellType => {
+            this.extProxy.$terminalShellTypeChanged(terminal.id, shellType);
+        }));
         this.observers.forEach((observer, id) => this.observeTerminal(id, terminal, observer));
     }
 

packages/plugin-ext/src/plugin/terminal-ext.ts

@@ -161,13 +161,24 @@ export class TerminalServiceExtImpl implements TerminalServiceExt {
         terminal.emitOnInput(data);
     }
 
-    $terminalStateChanged(id: string): void {
+    $terminalOnInteraction(id: string): void {
         const terminal = this._terminals.get(id);
         if (!terminal) {
             return;
         }
         if (!terminal.state.isInteractedWith) {
-            terminal.state = { isInteractedWith: true };
+            terminal.state = { ...terminal.state, isInteractedWith: true };
+            this.onDidChangeTerminalStateEmitter.fire(terminal);
+        }
+    }
+
+    $terminalShellTypeChanged(id: string, shellType: string): void {
+        const terminal = this._terminals.get(id);
+        if (!terminal) {
+            return;
+        }
+        if (terminal.state.shell !== shellType) {
+            terminal.state = { ...terminal.state, shell: shellType };
             this.onDidChangeTerminalStateEmitter.fire(terminal);
         }
     }
@@ -472,7 +483,7 @@ export class TerminalExtImpl implements theia.Terminal {
 
     readonly creationOptions: Readonly<theia.TerminalOptions | theia.ExtensionTerminalOptions>;
 
-    state: theia.TerminalState = { isInteractedWith: false };
+    state: theia.TerminalState = { isInteractedWith: false, shell: undefined };
 
     constructor(private readonly proxy: TerminalServiceMain, private readonly options: theia.TerminalOptions | theia.ExtensionTerminalOptions) {
         this.creationOptions = this.options;

packages/plugin/src/theia.d.ts

@@ -3146,6 +3146,21 @@ export module '@theia/plugin' {
          * https://invisible-island.net/xterm/ctlseqs/ctlseqs.html
          */
         readonly isInteractedWith: boolean;
+
+        /**
+         * The detected shell type of the {@link Terminal}. This will be `undefined` when there is
+         * not a clear signal as to what the shell is, or the shell is not supported yet. This
+         * value should change to the shell type of a sub-shell when launched (for example, running
+         * `bash` inside `zsh`).
+         *
+         * Note that current implementation only assess the shell type on terminal creation, and it is
+         * not updated if a sub-shell is currnetly launched.
+         *
+         * Note that the possible values are currently defined as any of the following:
+         * 'bash', 'cmd', 'csh', 'fish', 'gitbash', 'julia', 'ksh', 'node', 'nu', 'pwsh', 'python',
+         * 'sh', 'wsl', 'zsh'.
+         */
+        readonly shell: string | undefined;
     }
 
     /**

packages/terminal/src/browser/base/terminal-widget.ts

@@ -128,6 +128,9 @@ export abstract class TerminalWidget extends BaseWidget {
     /** Event that fires when the terminal input data */
     abstract onData: Event<string>;
 
+    /** Event that fires when the terminal shell type is changed */
+    abstract onShellTypeChanged: Event<string>;
+
     abstract onOutput: Event<string>;
 
     abstract buffer: TerminalBuffer;

packages/terminal/src/browser/terminal-widget-impl.ts

@@ -50,6 +50,8 @@ import { EnhancedPreviewWidget } from '@theia/core/lib/browser/widgets/enhanced-
 import { MarkdownRenderer, MarkdownRendererFactory } from '@theia/core/lib/browser/markdown-rendering/markdown-renderer';
 import { RemoteConnectionProvider, ServiceConnectionProvider } from '@theia/core/lib/browser/messaging/service-connection-provider';
 import { ColorRegistry } from '@theia/core/lib/browser/color-registry';
+import { GeneralShellType, WindowsShellType } from '../common/terminal';
+import * as path from 'path';
 
 export const TERMINAL_WIDGET_FACTORY_ID = 'terminal';
 
@@ -157,6 +159,9 @@ export class TerminalWidgetImpl extends TerminalWidget implements StatefulWidget
     protected readonly onMouseLeaveLinkHoverEmitter = new Emitter<MouseEvent>();
     readonly onMouseLeaveLinkHover: Event<MouseEvent> = this.onMouseLeaveLinkHoverEmitter.event;
 
+    protected readonly onShellTypeChangedEmiter = new Emitter<string>();
+    readonly onShellTypeChanged: Event<string> = this.onShellTypeChangedEmiter.event;
+
     protected readonly toDisposeOnConnect = new DisposableCollection();
 
     private _buffer: TerminalBuffer;
@@ -260,6 +265,7 @@ export class TerminalWidgetImpl extends TerminalWidget implements StatefulWidget
         this.toDispose.push(this.onSizeChangedEmitter);
         this.toDispose.push(this.onDataEmitter);
         this.toDispose.push(this.onKeyEmitter);
+        this.toDispose.push(this.onShellTypeChangedEmiter);
 
         const touchEndListener = (event: TouchEvent) => {
             if (this.node.contains(event.target as Node)) {
@@ -589,7 +595,6 @@ export class TerminalWidgetImpl extends TerminalWidget implements StatefulWidget
             rootURI = root?.resource?.toString();
         }
         const { cols, rows } = this.term;
-
         const terminalId = await this.shellTerminalServer.create({
             shell: this.options.shellPath || this.shellPreferences.shell[OS.backend.type()],
             args: this.options.shellArgs || this.shellPreferences.shellArgs[OS.backend.type()],
@@ -601,6 +606,11 @@ export class TerminalWidgetImpl extends TerminalWidget implements StatefulWidget
             rows
         });
         if (IBaseTerminalServer.validateId(terminalId)) {
+            const processInfo = await this.shellTerminalServer.getProcessInfo(terminalId);
+            const shellType = guessShellTypeFromExecutable(processInfo.executable);
+            if (shellType) {
+                this.onShellTypeChangedEmiter.fire(shellType);
+            }
             return terminalId;
         }
         throw new Error('Error creating terminal widget, see the backend error log for more information.');
@@ -675,7 +685,7 @@ export class TerminalWidgetImpl extends TerminalWidget implements StatefulWidget
         const waitForConnection = this.waitForConnection = new Deferred<Channel>();
         this.connectionProvider.listen(
             `${terminalsPath}/${this.terminalId}`,
-            (path, connection) => {
+            (_path, connection) => {
                 connection.onMessage(e => {
                     this.write(e().readString());
                 });
@@ -995,3 +1005,44 @@ export class TerminalWidgetImpl extends TerminalWidget implements StatefulWidget
         return this.enhancedPreviewNode;
     }
 }
+
+function guessShellTypeFromExecutable(executable: string | undefined): string | undefined {
+    if (!executable) {
+        return undefined;
+    }
+
+    const executableName = path.basename(executable);
+    // windows tested first, as gitbash may be confused with other OS bash
+    if (OS.backend.isWindows) {
+        const windowShellTypesToRegex: Map<string, RegExp> = new Map([
+            [WindowsShellType.CommandPrompt, /^cmd$/],
+            [WindowsShellType.GitBash, /^bash$/],
+            [WindowsShellType.Wsl, /^wsl$/]
+        ]);
+        for (const [shellType, pattern] of windowShellTypesToRegex) {
+            if (executableName.match(pattern)) {
+                return shellType;
+            }
+        }
+    }
+
+    const shellTypesToRegex: Map<string, RegExp> = new Map([
+        [GeneralShellType.Bash, /^bash$/],
+        [GeneralShellType.Csh, /^csh$/],
+        [GeneralShellType.Fish, /^fish$/],
+        [GeneralShellType.Julia, /^julia$/],
+        [GeneralShellType.Ksh, /^ksh$/],
+        [GeneralShellType.Node, /^node$/],
+        [GeneralShellType.NuShell, /^nu$/],
+        [GeneralShellType.PowerShell, /^pwsh(-preview)?|powershell$/],
+        [GeneralShellType.Python, /^py(?:thon)?$/],
+        [GeneralShellType.Sh, /^sh$/],
+        [GeneralShellType.Zsh, /^zsh$/]
+    ]);
+    for (const [shellType, pattern] of shellTypesToRegex) {
+        if (executableName.match(pattern)) {
+            return shellType;
+        }
+    }
+    return undefined;
+}

packages/terminal/src/common/terminal.ts

@@ -0,0 +1,36 @@
+// *****************************************************************************
+// Copyright (C) 2025 STMicroelectronics and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+export const enum GeneralShellType {
+    Bash = 'bash',
+    Csh = 'csh',
+    Fish = 'fish',
+    Julia = 'julia',
+    Ksh = 'ksh',
+    Node = 'node',
+    NuShell = 'nu',
+    PowerShell = 'pwsh',
+    Python = 'python',
+    Sh = 'sh',
+    Zsh = 'zsh',
+}
+
+export const enum WindowsShellType {
+    CommandPrompt = 'cmd',
+    GitBash = 'gitbash',
+    Wsl = 'wsl'
+}
+
+export type ShellType = GeneralShellType | WindowsShellType;