Skylark debugging protocol: include frames information in ThreadPausedEvents.

This is almost always desirable -- if a thread is paused, the IDE expects
to know the context.

PiperOrigin-RevId: 199865078

3 files changed, 16 insertions, 3 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skylarkdebug/proto/skylark_debugging.proto b/src/main/java/com/google/devtools/build/lib/skylarkdebug/proto/skylark_debugging.proto
index ed398e70fa..649f2936e2 100644
--- a/src/main/java/com/google/devtools/build/lib/skylarkdebug/proto/skylark_debugging.proto
+++ b/src/main/java/com/google/devtools/build/lib/skylarkdebug/proto/skylark_debugging.proto
@@ -184,6 +184,11 @@ message ThreadEndedEvent {
 message ThreadPausedEvent {
   // The thread that was paused.
   Thread thread = 1;
+
+  // The list of stack frames for the paused thread. The first element in the
+  // list represents the topmost frame (that is, the current innermost
+  // function).
+  repeated Frame frame = 2;
 }
 
 // An event indicating that a thread has continued execution after being paused.
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkdebug/server/DebugEventHelper.java b/src/main/java/com/google/devtools/build/lib/skylarkdebug/server/DebugEventHelper.java
index 0254484062..aa2279f97d 100644
--- a/src/main/java/com/google/devtools/build/lib/skylarkdebug/server/DebugEventHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/skylarkdebug/server/DebugEventHelper.java
@@ -130,9 +130,9 @@ final class DebugEventHelper {
         .build();
   }
 
-  static DebugEvent threadPausedEvent(Thread thread) {
+  static DebugEvent threadPausedEvent(Thread thread, Collection<Frame> frames) {
     return DebugEvent.newBuilder()
-        .setThreadPaused(ThreadPausedEvent.newBuilder().setThread(thread))
+        .setThreadPaused(ThreadPausedEvent.newBuilder().setThread(thread).addAllFrame(frames))
         .build();
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkdebug/server/ThreadHandler.java b/src/main/java/com/google/devtools/build/lib/skylarkdebug/server/ThreadHandler.java
index fd30c64e01..e1f74f9dd6 100644
--- a/src/main/java/com/google/devtools/build/lib/skylarkdebug/server/ThreadHandler.java
+++ b/src/main/java/com/google/devtools/build/lib/skylarkdebug/server/ThreadHandler.java
@@ -225,6 +225,11 @@ final class ThreadHandler {
     }
     // no need to list frames within the synchronize block: threads can only be resumed in response
     // to a client request, and requests are handled serially
+    return listFrames(debuggable, pausedState);
+  }
+
+  private static ImmutableList<SkylarkDebuggingProtos.Frame> listFrames(
+      Debuggable debuggable, PausedThreadState pausedState) {
     return debuggable
         .listFrames(pausedState.location)
         .stream()
@@ -265,6 +270,7 @@ final class ThreadHandler {
 
     SkylarkDebuggingProtos.Thread threadProto;
     PausedThreadState pausedState;
+    Debuggable debuggable;
     synchronized (threads) {
       ThreadState thread = threads.get(threadId);
       if (thread == null) {
@@ -276,13 +282,15 @@ final class ThreadHandler {
         transport.postEvent(DebugEventHelper.threadStartedEvent(threadId, fallbackThreadName));
         thread = doRegisterThread(threadId, fallbackThreadName, env);
       }
+      debuggable = thread.debuggable;
       pausedState = new PausedThreadState(location);
       thread.pausedState = pausedState;
       // get proto after setting the paused state, so that it's up to date
       threadProto = getThreadProto(thread);
     }
 
-    transport.postEvent(DebugEventHelper.threadPausedEvent(threadProto));
+    transport.postEvent(
+        DebugEventHelper.threadPausedEvent(threadProto, listFrames(debuggable, pausedState)));
     pausedState.semaphore.acquireUninterruptibly();
     transport.postEvent(
         DebugEventHelper.threadContinuedEvent(