Catch and dump unhandled exceptions in async task functions

The problem with relying on noexcept for this is that there is no stack.

1 files changed, 6 insertions, 0 deletions

diff --git a/build2/test/rule.cxx b/build2/test/rule.cxx
index 5cec891..0e1aff6 100644
--- a/build2/test/rule.cxx
+++ b/build2/test/rule.cxx
@@ -397,6 +397,12 @@ namespace build2
       {
         r = scope_state::failed;
       }
+      catch (const std::exception& e)
+      {
+        *diag_stream << "unhandled exception: " << e;
+        assert (false);
+        abort ();
+      }
 
       return r;
     }