[vscode] Support EnvironmentVariableCollection description #12696

* add new field to EnvironmentVariableCollection and implement interface

Contributed on behalf of STMicroelectronics

Signed-off-by: Johannes Faltermeier <jfaltermeier@eclipsesource.com>

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

@@ -14,7 +14,7 @@
 // SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
 // *****************************************************************************
 import { UUID } from '@theia/core/shared/@phosphor/coreutils';
-import { Terminal, TerminalOptions, PseudoTerminalOptions, ExtensionTerminalOptions, TerminalState } from '@theia/plugin';
+import { Terminal, TerminalOptions, PseudoTerminalOptions, ExtensionTerminalOptions, TerminalState, MarkdownString } from '@theia/plugin';
 import { TerminalServiceExt, TerminalServiceMain, PLUGIN_RPC_CONTEXT } from '../common/plugin-api-rpc';
 import { RPCProtocol } from '../common/rpc-protocol';
 import { Event, Emitter } from '@theia/core/lib/common/event';
@@ -339,8 +339,15 @@ export class TerminalServiceExtImpl implements TerminalServiceExt {
 
 export class EnvironmentVariableCollection implements theia.EnvironmentVariableCollection {
     readonly map: Map<string, theia.EnvironmentVariableMutator> = new Map();
+    private _description?: string | MarkdownString;
     private _persistent: boolean = true;
 
+    public get description(): string | MarkdownString | undefined { return this._description; }
+    public set description(value: string | MarkdownString | undefined) {
+        this._description = value;
+        this.onDidChangeCollectionEmitter.fire();
+    }
+
     public get persistent(): boolean { return this._persistent; }
     public set persistent(value: boolean) {
         this._persistent = value;

packages/plugin/src/theia.d.ts

@@ -3585,6 +3585,12 @@ export module '@theia/plugin' {
      * A collection of mutations that an extension can apply to a process environment.
      */
     export interface EnvironmentVariableCollection {
+
+        /**
+         * A description for the environment variable collection, this will be used to describe the changes in the UI.
+         */
+        description: string | MarkdownString | undefined;
+
         /**
          * Whether the collection should be cached for the workspace and applied to the terminal
          * across window reloads. When true the collection will be active immediately such when the