Add support to de-emphasize debuggers in run list

src/vs/workbench/contrib/debug/browser/debugAdapterManager.ts

@@ -364,6 +364,7 @@ export class AdapterManager extends Disposable implements IAdapterManager {
 		this.initExtensionActivationsIfNeeded();
 
 		candidates.sort((first, second) => first.label.localeCompare(second.label));
+		candidates = candidates.filter(a => !a.isHiddenFromDropdown);
 
 		const suggestedCandidates: Debugger[] = [];
 		const otherCandidates: Debugger[] = [];

src/vs/workbench/contrib/debug/common/debug.ts

@@ -839,6 +839,7 @@ export interface IDebuggerContribution extends IPlatformSpecificAdapterContribut
 	configurationSnippets?: IJSONSchemaSnippet[];
 	variables?: { [key: string]: string };
 	when?: string;
+	hiddenWhen?: string;
 	deprecated?: string;
 	strings?: { [key in DebuggerString]: string };
 }

src/vs/workbench/contrib/debug/common/debugSchemas.ts

@@ -72,6 +72,11 @@ export const debuggersExtPoint = extensionsRegistry.ExtensionsRegistry.registerE
 					type: 'string',
 					default: ''
 				},
+				hiddenWhen: {
+					description: nls.localize('vscode.extension.contributes.debuggers.hiddenWhen', "When this condition is true, this debugger type is hidden from the debugger list, but is still enabled."),
+					type: 'string',
+					default: ''
+				},
 				deprecated: {
 					description: nls.localize('vscode.extension.contributes.debuggers.deprecated', "Optional message to mark this debug type as being deprecated."),
 					type: 'string',

src/vs/workbench/contrib/debug/common/debugger.ts

@@ -29,6 +29,7 @@ export class Debugger implements IDebugger, IDebuggerMetadata {
 	private mainExtensionDescription: IExtensionDescription | undefined;
 
 	private debuggerWhen: ContextKeyExpression | undefined;
+	private debuggerHiddenWhen: ContextKeyExpression | undefined;
 
 	constructor(
 		private adapterManager: IAdapterManager,
@@ -45,6 +46,7 @@ export class Debugger implements IDebugger, IDebuggerMetadata {
 		this.merge(dbgContribution, extensionDescription);
 
 		this.debuggerWhen = typeof this.debuggerContribution.when === 'string' ? ContextKeyExpr.deserialize(this.debuggerContribution.when) : undefined;
+		this.debuggerHiddenWhen = typeof this.debuggerContribution.hiddenWhen === 'string' ? ContextKeyExpr.deserialize(this.debuggerContribution.hiddenWhen) : undefined;
 	}
 
 	merge(otherDebuggerContribution: IDebuggerContribution, extensionDescription: IExtensionDescription): void {
@@ -147,10 +149,21 @@ export class Debugger implements IDebugger, IDebuggerMetadata {
 		return this.debuggerWhen;
 	}
 
+	get hiddenWhen(): ContextKeyExpression | undefined {
+		return this.debuggerHiddenWhen;
+	}
+
 	get enabled() {
 		return !this.debuggerWhen || this.contextKeyService.contextMatchesRules(this.debuggerWhen);
 	}
 
+	get isHiddenFromDropdown() {
+		if (!this.debuggerHiddenWhen) {
+			return false;
+		}
+		return this.contextKeyService.contextMatchesRules(this.debuggerHiddenWhen);
+	}
+
 	get strings() {
 		return this.debuggerContribution.strings ?? (this.debuggerContribution as any).uiMessages;
 	}