Reland "[lldb][target] Add progress report for wait-attaching to proc…

lldb/source/Target/Target.cpp

@@ -3546,6 +3546,7 @@ llvm::Expected<TraceSP> Target::GetTraceOrCreate() {
 }
 
 Status Target::Attach(ProcessAttachInfo &attach_info, Stream *stream) {
+  Progress attach_progress("Waiting to attach to process");
   m_stats.SetLaunchOrAttachTime();
   auto state = eStateInvalid;
   auto process_sp = GetProcessSP();

lldb/test/API/functionalities/progress_reporting/TestProgressReporting.py

@@ -16,6 +16,28 @@ def setUp(self):
             self.broadcaster, lldb.SBDebugger.eBroadcastBitProgress
         )
 
+    def test_wait_attach_progress_reporting(self):
+        """Test that progress reports for wait attaching work as intended."""
+        target = self.dbg.CreateTarget(None)
+
+        # The waiting to attach progress message will get emitted upon
+        # trying to attach, but it's not going to be the event picked
+        # up by checking with fetch_next_event, so go through all emitted
+        # progress events and check that the waiting to attach one was emitted at all.
+        target.AttachToProcessWithName(
+            self.listener,
+            "wait-attach-progress-report",
+            False,
+            lldb.SBError(),
+        )
+        event = lldb.SBEvent()
+        events = []
+        while self.listener.GetNextEventForBroadcaster(self.broadcaster, event):
+            progress_data = lldb.SBDebugger.GetProgressDataFromEvent(event)
+            message = progress_data.GetValueForKey("message").GetStringValue(100)
+            events.append(message)
+        self.assertTrue("Waiting to attach to process" in events)
+
     def test_dwarf_symbol_loading_progress_report(self):
         """Test that we are able to fetch dwarf symbol loading progress events"""
         self.build()