bitbake: bb.build: in _exec_task, catch errors from TaskStarted

We don't always want a traceback when an exception is raised by the
TaskStarted event handler. Silently return if we get a SystemExit or
HandledException, and print the error and return for FuncFailed.

This is done via a separate try/catch block, to avoid firing TaskFailed if all
the TaskStarted event handlers didn't complete, otherwise the bitbake UIs get
unhappy.

(Bitbake rev: ca5b788280ad4303cc08a376e847cbbeda31970c)

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/build.py

@@ -565,7 +565,15 @@ def _exec_task(fn, task, d, quieterr):
 
     flags = localdata.getVarFlags(task)
 
+    try:
+        try:
             event.fire(TaskStarted(task, logfn, flags, localdata), localdata)
+        except (bb.BBHandledException, SystemExit):
+            return 1
+        except FuncFailed as exc:
+            logger.error(str(exc))
+            return 1
+
         try:
             for func in (prefuncs or '').split():
                 exec_func(func, localdata)