From f5867d6b1f0c256d191ea4fdf8a9855711773484 Mon Sep 17 00:00:00 2001
From: Samuel Frylmark <samuel.frylmark@ericsson.com>
Date: Thu, 9 Jan 2020 14:26:43 +0100
Subject: [PATCH] [debug] Lazily update frames of all threads in all-stop mode

When a breakpoint occurs in a thread in all-stop mode, all other
threads have outdated/missing stackframes which means no variables
show up and can be inspected. This fixes the issue by marking each
thread as potentially having "dirty" frames: frames that need to be
re-fetched when the user selects them.

Signed-off-by: Samuel Frylmark <samuel.frylmark@ericsson.com>
---
 packages/debug/src/browser/debug-session.tsx      | 8 +++++++-
 packages/debug/src/browser/model/debug-thread.tsx | 7 +++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/packages/debug/src/browser/debug-session.tsx b/packages/debug/src/browser/debug-session.tsx
index 30cb93d9f00d0..d04990c67bbce 100644
--- a/packages/debug/src/browser/debug-session.tsx
+++ b/packages/debug/src/browser/debug-session.tsx
@@ -93,7 +93,10 @@ export class DebugSession implements CompositeTreeElement {
                 }
             }),
             this.on('stopped', async ({ body }) => {
+                // Update thread list
                 await this.updateThreads(body);
+
+                // Update current thread's frames immediately
                 await this.updateFrames();
             }),
             this.on('thread', ({ body: { reason, threadId } }) => {
@@ -221,6 +224,9 @@ export class DebugSession implements CompositeTreeElement {
         this.fireDidChange();
         if (thread) {
             this.toDisposeOnCurrentThread.push(thread.onDidChanged(() => this.fireDidChange()));
+
+            // If this thread is missing stack frame information, then load that.
+            this.updateFrames();
         }
     }
 
@@ -465,7 +471,7 @@ export class DebugSession implements CompositeTreeElement {
 
     protected async updateFrames(): Promise<void> {
         const thread = this._currentThread;
-        if (!thread || thread.frameCount) {
+        if (!thread || thread.pendingFrameCount || thread.frameCount) {
             return;
         }
         if (this.capabilities.supportsDelayedStackTraceLoading) {
diff --git a/packages/debug/src/browser/model/debug-thread.tsx b/packages/debug/src/browser/model/debug-thread.tsx
index c5225bc202230..b9442b93128dd 100644
--- a/packages/debug/src/browser/model/debug-thread.tsx
+++ b/packages/debug/src/browser/model/debug-thread.tsx
@@ -140,7 +140,9 @@ export class DebugThread extends DebugThreadData implements TreeElement {
     }
 
     protected pendingFetch = Promise.resolve<DebugStackFrame[]>([]);
+    protected _pendingFetchCount: number = 0;
     async fetchFrames(levels: number = 20): Promise<DebugStackFrame[]> {
+        this._pendingFetchCount += 1;
         return this.pendingFetch = this.pendingFetch.then(async () => {
             try {
                 const start = this.frameCount;
@@ -149,9 +151,14 @@ export class DebugThread extends DebugThreadData implements TreeElement {
             } catch (e) {
                 console.error(e);
                 return [];
+            } finally {
+                this._pendingFetchCount -= 1;
             }
         });
     }
+    get pendingFrameCount(): number {
+        return this._pendingFetchCount;
+    }
     protected async doFetchFrames(startFrame: number, levels: number): Promise<DebugProtocol.StackFrame[]> {
         try {
             const response = await this.session.sendRequest('stackTrace',