fixes #25104

src/vs/workbench/parts/debug/common/debugModel.ts

@@ -24,7 +24,6 @@ import { Source } from 'vs/workbench/parts/debug/common/debugSource';
 import { IWorkbenchEditorService } from 'vs/workbench/services/editor/common/editorService';
 
 const MAX_REPL_LENGTH = 10000;
-const UNKNOWN_SOURCE_LABEL = nls.localize('unknownSource', "Unknown Source");
 
 export abstract class AbstractOutputElement implements ITreeElement {
 	private static ID_COUNTER = 0;
@@ -388,7 +387,7 @@ export class StackFrame implements IStackFrame {
 
 	public openInEditor(editorService: IWorkbenchEditorService, preserveFocus?: boolean, sideBySide?: boolean): TPromise<any> {
 
-		return this.source.name === UNKNOWN_SOURCE_LABEL ? TPromise.as(null) : editorService.openEditor({
+		return !this.source.available ? TPromise.as(null) : editorService.openEditor({
 			resource: this.source.uri,
 			description: this.source.origin,
 			options: {
@@ -466,10 +465,7 @@ export class Thread implements IThread {
 			}
 
 			return response.body.stackFrames.map((rsf, level) => {
-				if (!rsf) {
-					return new StackFrame(this, 0, new Source({ name: UNKNOWN_SOURCE_LABEL }, rsf.presentationHint), nls.localize('unknownStack', "Unknown stack location"), null, null);
-				}
-				let source = rsf.source ? new Source(rsf.source, rsf.source.presentationHint) : new Source({ name: UNKNOWN_SOURCE_LABEL }, rsf.presentationHint);
+				let source = new Source(rsf.source, rsf.source ? rsf.source.presentationHint : rsf.presentationHint);
 				if (this.process.sources.has(source.uri.toString())) {
 					const alreadyCreatedSource = this.process.sources.get(source.uri.toString());
 					alreadyCreatedSource.presenationHint = source.presenationHint;

src/vs/workbench/parts/debug/common/debugSource.ts

@@ -3,16 +3,22 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
+import * as nls from 'vs/nls';
 import uri from 'vs/base/common/uri';
 import { DEBUG_SCHEME } from 'vs/workbench/parts/debug/common/debug';
 
+const UNKNOWN_SOURCE_LABEL = nls.localize('unknownSource', "Unknown Source");
+
 export class Source {
 
 	public uri: uri;
 
 	constructor(public raw: DebugProtocol.Source, public presenationHint: string) {
-		const path = raw.path || raw.name;
-		this.uri = raw.sourceReference > 0 ? uri.parse(`${DEBUG_SCHEME}:${path}`) : uri.file(path);
+		if (!raw) {
+			this.raw = { name: UNKNOWN_SOURCE_LABEL };
+		}
+		const path = this.raw.path || this.raw.name;
+		this.uri = this.raw.sourceReference > 0 ? uri.parse(`${DEBUG_SCHEME}:${path}`) : uri.file(path);
 	}
 
 	public get name() {
@@ -27,6 +33,10 @@ export class Source {
 		return this.raw.sourceReference;
 	}
 
+	public get available() {
+		return this.raw.name !== UNKNOWN_SOURCE_LABEL;
+	}
+
 	public get inMemory() {
 		return this.uri.toString().indexOf(`${DEBUG_SCHEME}:`) === 0;
 	}

src/vs/workbench/parts/debug/electron-browser/debugService.ts

@@ -294,7 +294,7 @@ export class DebugService implements debug.IDebugService {
 					thread.fetchCallStack().then(callStack => {
 						if (callStack.length > 0 && !this.viewModel.focusedStackFrame) {
 							// focus first stack frame from top that has source location if no other stack frame is focussed
-							const stackFrameToFocus = first(callStack, sf => !!sf.source, callStack[0]);
+							const stackFrameToFocus = first(callStack, sf => sf.source && sf.source.available, callStack[0]);
 							this.focusStackFrameAndEvaluate(stackFrameToFocus).done(null, errors.onUnexpectedError);
 							this.windowService.getWindow().focus();
 							aria.alert(nls.localize('debuggingPaused', "Debugging paused, reason {0}, {1} {2}", event.body.reason, stackFrameToFocus.source ? stackFrameToFocus.source.name : '', stackFrameToFocus.lineNumber));