Add stacktrace dump and better error messages on EXC_BAD_ACCESS panics

Fixes #1903

Author: lggomez

package-lock.json

@@ -1445,9 +1445,7 @@ class GoDebugSession extends LoggingDebugSession {
 
 		// If called when setting breakpoint internally, we want the error to bubble up.
 		const errorCallback = calledWhenSettingBreakpoint ? null : (err: any) => {
-			if (err) {
-				logError('Failed to continue - ' + err.toString());
-			}
+			this.logDelveError(err, 'Failed to continue');
 			this.handleReenterDebug('breakpoint');
 			throw err;
 		};
@@ -1466,7 +1464,7 @@ class GoDebugSession extends LoggingDebugSession {
 		log('NextRequest');
 		this.delve.call<DebuggerState | CommandOut>('Command', [{ name: 'next' }], (err, out) => {
 			if (err) {
-				logError('Failed to next - ' + err.toString());
+				this.logDelveError(err, 'Failed to next');
 			}
 			const state = this.delve.isApiV1 ? <DebuggerState>out : (<CommandOut>out).State;
 			log('next state', state);
@@ -1481,7 +1479,7 @@ class GoDebugSession extends LoggingDebugSession {
 		log('StepInRequest');
 		this.delve.call<DebuggerState | CommandOut>('Command', [{ name: 'step' }], (err, out) => {
 			if (err) {
-				logError('Failed to step - ' + err.toString());
+				this.logDelveError(err, 'Failed to step - ');
 			}
 			const state = this.delve.isApiV1 ? <DebuggerState>out : (<CommandOut>out).State;
 			log('stop state', state);
@@ -1496,7 +1494,7 @@ class GoDebugSession extends LoggingDebugSession {
 		log('StepOutRequest');
 		this.delve.call<DebuggerState | CommandOut>('Command', [{ name: 'stepOut' }], (err, out) => {
 			if (err) {
-				logError('Failed to stepout - ' + err.toString());
+				this.logDelveError(err, 'Failed to stepout - ');
 			}
 			const state = this.delve.isApiV1 ? <DebuggerState>out : (<CommandOut>out).State;
 			log('stepout state', state);
@@ -1587,6 +1585,59 @@ class GoDebugSession extends LoggingDebugSession {
 		});
 	}
 
+	private logDelveError(err: any, message: string) {
+		if (err) {
+			let errorMessage = err.toString();
+			// Handle unpropagated fatalpanic errors with a more user friendly message:
+			// https://github.com/microsoft/vscode-go/issues/1903#issuecomment-460126884
+			// https://github.com/go-delve/delve/issues/852
+			// This affects macOS only although we're agnostic of the OS at this stage, only handle the error
+			if (errorMessage === 'bad access') {
+				errorMessage = 'unpropagated fatalpanic: signal SIGSEGV (EXC_BAD_ACCESS). This fatalpanic is not traceable on macOS, see https://github.com/go-delve/delve/issues/852';
+			}
+			logError(message + ' - ' + errorMessage);
+		}
+		this.dumpStacktrace();
+	}
+
+	private dumpStacktrace() {
+		const goroutineId = 0;
+		const stackTraceIn = { id: goroutineId, depth: this.delve.stackTraceDepth };
+		if (!this.delve.isApiV1) {
+			Object.assign(stackTraceIn, { full: false, cfg: this.delve.loadConfig });
+		}
+		this.delve.call<DebugLocation[] | StacktraceOut>(this.delve.isApiV1 ? 'StacktraceGoroutine' : 'Stacktrace', [stackTraceIn], (err, out) => {
+			if (err) {
+				logError('Failed to produce stack trace!');
+				return;
+			}
+			const locations = this.delve.isApiV1 ? <DebugLocation[]>out : (<StacktraceOut>out).Locations;
+			log('locations', locations);
+			const stackFrames = locations.map((location, frameId) => {
+				const uniqueStackFrameId = this.stackFrameHandles.create([goroutineId, frameId]);
+				return new StackFrame(
+					uniqueStackFrameId,
+					location.function ? location.function.name : '<unknown>',
+					location.file === '<autogenerated>' ? null : new Source(
+						basename(location.file),
+						this.toLocalPath(location.file)
+					),
+					location.line,
+					0
+				);
+			});
+			logError('Immediate stacktrace:');
+			let output = '';
+			stackFrames.forEach(stackFrame => {
+				output = output.concat(`\t${stackFrame.source.path}:${stackFrame.line}\n`);
+				if (stackFrame.name) {
+					output = output.concat(`\t\t${stackFrame.name}\n`);
+				}
+			});
+			logError(output);
+		});
+	}
+
 	private addFullyQualifiedName(variables: DebugVariable[]) {
 		variables.forEach(local => {
 			local.fullyQualifiedName = local.name;