[PATCH] runqueue: Sanity check BB_NUMBER_THREADS

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

Bitbake does really weird things with negative or zero numbers of threads
which is confusing to the user. Add a sanity check for this.

When you have code doing arithmetic on the values and a VM reconfigures
to only a single thread, negative numbers are easier than you'd think.

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

diff --git a/bitbake/lib/bb/runqueue.py b/bitbake/lib/bb/runqueue.py
index a5ae42b..3f62453 100644
--- a/bitbake/lib/bb/runqueue.py
+++ b/bitbake/lib/bb/runqueue.py
@@ -1333,6 +1333,9 @@ class RunQueueExecute:
         if rq.fakeworkerpipe:
             rq.fakeworkerpipe.setrunqueueexec(self)
 
+        if self.number_tasks <= 0:
+             bb.fatal("Invalid BB_NUMBER_THREADS %s" % self.number_tasks)
+
     def runqueue_process_waitpid(self, task, status):
 
         # self.build_stamps[pid] may not exist when use shared work directory.