[PATCH] taskdata: Fix traceback issue with missing provider

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

If there is a missing provider and we're using "-k" mode alongside "-w",
we could get a traceback since there was no provider. Add tests to avoid this.

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

diff --git a/bitbake/lib/bb/taskdata.py b/bitbake/lib/bb/taskdata.py
index 6e4d149..9ae52d7 100644
--- a/bitbake/lib/bb/taskdata.py
+++ b/bitbake/lib/bb/taskdata.py
@@ -642,7 +642,9 @@ class TaskData:
             if prefix and not name.startswith(prefix):
                 continue
             if self.have_build_target(name):
-                provmap[name] = self.fn_index[self.get_provider(name)[0]]
+                provider = self.get_provider(name)
+                if provider:
+                    provmap[name] = self.fn_index[provider[0]]
         return provmap
 
     def dump_data(self):