debug: more precise computatino of top stack frame call stack decoration

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

@@ -48,8 +48,8 @@ export function createDecorationsForStackFrame(stackFrame: IStackFrame, topStack
 
 	// compute how to decorate the editor. Different decorations are used if this is a top stack frame, focused stack frame,
 	// an exception or a stack frame that did not change the line number (we only decorate the columns, not the whole line).
-	const callStack = stackFrame.thread.getCallStack();
-	if (callStack && callStack.length && stackFrame === callStack[0]) {
+	const topStackFrame = stackFrame.thread.getTopStackFrame();
+	if (stackFrame.getId() === topStackFrame?.getId()) {
 		result.push({
 			options: TOP_STACK_FRAME_MARGIN,
 			range

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

@@ -6,7 +6,7 @@
 import * as nls from 'vs/nls';
 import { Event, Emitter } from 'vs/base/common/event';
 import { URI as uri } from 'vs/base/common/uri';
-import { first, distinct } from 'vs/base/common/arrays';
+import { distinct } from 'vs/base/common/arrays';
 import * as errors from 'vs/base/common/errors';
 import severity from 'vs/base/common/severity';
 import * as aria from 'vs/base/browser/ui/aria/aria';
@@ -991,11 +991,8 @@ export function getStackFrameThreadAndSessionToFocus(model: IDebugModel, stackFr
 		}
 	}
 
-	if (!stackFrame) {
-		if (thread) {
-			const callStack = thread.getCallStack();
-			stackFrame = first(callStack, sf => !!(sf && sf.source && sf.source.available && sf.source.presentationHint !== 'deemphasize'), undefined);
-		}
+	if (!stackFrame && thread) {
+		stackFrame = thread.getTopStackFrame();
 	}
 
 	return { session, thread, stackFrame };

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

@@ -288,6 +288,12 @@ export interface IThread extends ITreeElement {
 	 */
 	getCallStack(): ReadonlyArray<IStackFrame>;
 
+
+	/**
+	 * Gets the top stack frame that is not hidden if the callstack has already been received from the debug adapter
+	 */
+	getTopStackFrame(): IStackFrame | undefined;
+
 	/**
 	 * Invalidates the callstack cache
 	 */

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

@@ -10,7 +10,7 @@ import { Event, Emitter } from 'vs/base/common/event';
 import { generateUuid } from 'vs/base/common/uuid';
 import { RunOnceScheduler } from 'vs/base/common/async';
 import { isString, isUndefinedOrNull } from 'vs/base/common/types';
-import { distinct, lastIndex } from 'vs/base/common/arrays';
+import { distinct, lastIndex, first } from 'vs/base/common/arrays';
 import { Range, IRange } from 'vs/editor/common/core/range';
 import {
 	ITreeElement, IExpression, IExpressionContainer, IDebugSession, IStackFrame, IExceptionBreakpoint, IBreakpoint, IFunctionBreakpoint, IDebugModel,
@@ -398,6 +398,10 @@ export class Thread implements IThread {
 		return this.staleCallStack;
 	}
 
+	getTopStackFrame(): IStackFrame | undefined {
+		return first(this.getCallStack(), sf => !!(sf && sf.source && sf.source.available && sf.source.presentationHint !== 'deemphasize'), undefined);
+	}
+
 	get stateLabel(): string {
 		if (this.stoppedDetails) {
 			return this.stoppedDetails.description ||

src/vs/workbench/contrib/debug/test/browser/callStack.test.ts

@@ -42,8 +42,8 @@ function createTwoStackFrames(session: DebugSession): { firstStackFrame: StackFr
 		sourceReference: 11,
 	}, 'aDebugSessionId');
 
-	firstStackFrame = new StackFrame(thread, 1, firstSource, 'app.js', 'normal', { startLineNumber: 1, startColumn: 1, endLineNumber: 1, endColumn: 10 }, 1);
-	secondStackFrame = new StackFrame(thread, 1, secondSource, 'app.js', 'normal', { startLineNumber: 1, startColumn: 1, endLineNumber: 1, endColumn: 10 }, 1);
+	firstStackFrame = new StackFrame(thread, 0, firstSource, 'app.js', 'normal', { startLineNumber: 1, startColumn: 1, endLineNumber: 1, endColumn: 10 }, 0);
+	secondStackFrame = new StackFrame(thread, 1, secondSource, 'app2.js', 'normal', { startLineNumber: 1, startColumn: 1, endLineNumber: 1, endColumn: 10 }, 1);
 
 	return { firstStackFrame, secondStackFrame };
 }