Ban multiple-dataset-type results in general find-first queries.

Supporting these would be extra complexity I don't think we need.
lsst · Oct 14, 2024 · 61ef7f7 · 61ef7f7
1 parent 8ba6a93
commit 61ef7f7
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/python/lsst/daf/butler/queries/result_specs.py b/python/lsst/daf/butler/queries/result_specs.py
@@ -221,6 +221,11 @@ class GeneralResultSpec(ResultSpecBase):
     def find_first_dataset(self) -> str | None:
         # Docstring inherited.
         if self.find_first:
+            if len(self.dataset_fields) != 1:
+                raise InvalidQueryError(
+                    "General query with find_first=True cannot have results from multiple "
+                    "dataset searches."
+                )
             (dataset_type,) = self.dataset_fields.keys()
             return dataset_type
         return None