[PATCH] event/server: Add _uiready flag to handle missing error messages

[Richard Purdie <richard.purdie@linuxfoundation.org>]

If you start and suspend a bitbake execution so the bitbake lock is held,
then try and run "bitbake -w '' X", you will see bitbake return an error exit
code but print no message about what happened at all.

The reason is that the -w option creates a "UI" which swallows the messages. The
code which handles this exit failure mode thinks a UI has printed the messages
and therefore doesn't do so.

This adds in an extra parameter to the UI registration code so that we
can figure out whether its a primary UI or not and base decisions on whether
to display information on that instead. This fixes the error shown above and
some bizarre failures on the Yocto Project Autobuilder.

[YOCTO #8239]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/bitbake/lib/bb/event.py b/bitbake/lib/bb/event.py
index da20fbf..059229e 100644
--- a/bitbake/lib/bb/event.py
+++ b/bitbake/lib/bb/event.py
@@ -69,6 +69,7 @@ _ui_handler_seq = 0
 _event_handler_map = {}
 _catchall_handlers = {}
 _eventfilter = None
+_uiready = False
 
 def execute_handler(name, handler, event, d):
     event.data = d
@@ -113,7 +117,7 @@ def print_ui_queue():
     """If we're exiting before a UI has been spawned, display any queued
     LogRecords to the console."""
     logger = logging.getLogger("BitBake")
-    if not _ui_handlers:
+    if not _uiready:
         from bb.msg import BBLogFormatter
         console = logging.StreamHandler(sys.stdout)
         console.setFormatter(BBLogFormatter("%(levelname)s: %(message)s"))
@@ -135,7 +139,7 @@ def print_ui_queue():
                 logger.handle(event)
 
 def fire_ui_handlers(event, d):
-    if not _ui_handlers:
+    if not _uiready:
         # No UI handlers registered yet, queue up the messages
         ui_queue.append(event)
         return
@@ -219,7 +223,9 @@ def set_eventfilter(func):
     global _eventfilter
     _eventfilter = func
 
-def register_UIHhandler(handler):
+def register_UIHhandler(handler, mainui=False):
+    if mainui:
+        _uiready = True
     bb.event._ui_handler_seq = bb.event._ui_handler_seq + 1
     _ui_handlers[_ui_handler_seq] = handler
     level, debug_domains = bb.msg.constructLogOptions()
diff --git a/bitbake/lib/bb/server/process.py b/bitbake/lib/bb/server/process.py
index 3198635..f022b86 100644
--- a/bitbake/lib/bb/server/process.py
+++ b/bitbake/lib/bb/server/process.py
@@ -97,7 +97,7 @@ class ProcessServer(Process, BaseImplServer):
     def run(self):
         for event in bb.event.ui_queue:
             self.event_queue.put(event)
-        self.event_handle.value = bb.event.register_UIHhandler(self)
+        self.event_handle.value = bb.event.register_UIHhandler(self, True)
 
         bb.cooker.server_main(self.cooker, self.main)
 
diff --git a/bitbake/lib/bb/server/xmlrpc.py b/bitbake/lib/bb/server/xmlrpc.py
index f1a2067..b7647c1 100644
--- a/bitbake/lib/bb/server/xmlrpc.py
+++ b/bitbake/lib/bb/server/xmlrpc.py
@@ -99,7 +99,7 @@ class BitBakeServerCommands():
         if (self.cooker.state in [bb.cooker.state.parsing, bb.cooker.state.running]):
             return None
 
-        self.event_handle = bb.event.register_UIHhandler(s)
+        self.event_handle = bb.event.register_UIHhandler(s, True)
         return self.event_handle
 
     def unregisterEventHandler(self, handlerNum):