Make record_module_build_arches idempotent

This function could get called multiple times if the init handler
runs more than once. This can happen if the build failed in the
init handler due to external infrastructure being down and the
user resumes their build.

module_build_service/scheduler/submit.py

@@ -104,7 +104,8 @@ def record_module_build_arches(mmd, build):
         arch_obj = db_session.query(models.ModuleArch).filter_by(name=arch).first()
         if not arch_obj:
             arch_obj = models.ModuleArch(name=arch)
-        build.arches.append(arch_obj)
+        if arch_obj not in build.arches:
+            build.arches.append(arch_obj)
 
     db_session.commit()
 

tests/test_scheduler/test_submit.py

@@ -87,6 +87,10 @@ class TestSubmit:
         arches = {arch.name for arch in build.arches}
         assert arches == set(get_build_arches.return_value)
 
+        # Ensure the function is idempotent
+        record_module_build_arches(build.mmd(), build)
+        assert len(build.arches) == len(get_build_arches.return_value)
+
     @pytest.mark.parametrize(
         "scmurl",
         [