Cleanup source selection in fetch_nwb by defaulting to Nwbfile

src/spyglass/utils/dj_mixin.py

@@ -259,15 +259,9 @@ def _nwb_table_tuple(self) -> tuple:
         resolved = getattr(self, "_nwb_table", None) or (
             AnalysisNwbfile
             if "-> AnalysisNwbfile" in self.definition
-            else Nwbfile if "-> Nwbfile" in self.definition else None
+            else Nwbfile
         )
 
-        if not resolved:
-            raise NotImplementedError(
-                f"{self.__class__.__name__} does not have a "
-                "(Analysis)Nwbfile foreign key or _nwb_table attribute."
-            )
-
         return (
             resolved,
             table_dict[resolved],
@@ -276,10 +270,10 @@ def _nwb_table_tuple(self) -> tuple:
     def fetch_nwb(self, *attrs, **kwargs):
         """Fetch NWBFile object from relevant table.
 
-        Implementing class must have a foreign key reference to Nwbfile or
-        AnalysisNwbfile (i.e., "-> (Analysis)Nwbfile" in definition)
-        or a _nwb_table attribute. If both are present, the attribute takes
-        precedence.
+        Data source is determined as follows:
+        1. If _nwb_table attribute is present, use it (takes precedence)
+        2. If "-> AnalysisNwbfile" foreign key exists in definition, use AnalysisNwbfile
+        3. Otherwise, default to Nwbfile
 
         Additional logic support Export table logging.
         """

tests/utils/test_mixin.py

@@ -27,10 +27,96 @@ def test_bad_prefix(caplog, dj_conn, Mixin):
     assert "Schema prefix not in SHARED_MODULES" in caplog.text
 
 
-def test_nwb_table_missing(schema_test, Mixin):
+def test_nwb_table_defaults_to_nwbfile(schema_test, Mixin, common):
     schema_test(Mixin)
-    with pytest.raises(NotImplementedError):
-        Mixin().fetch_nwb()
+    # Should default to Nwbfile instead of raising NotImplementedError
+    table, attr = Mixin()._nwb_table_tuple
+    assert table == common.Nwbfile, f"Expected Nwbfile as default, got {table}"
+    assert (
+        attr == "nwb_file_abs_path"
+    ), f"Expected nwb_file_abs_path, got {attr}"
+
+
+def test_nwb_table_tuple_comprehensive(schema_test, SpyglassMixin, common):
+    """Test _nwb_table_tuple logic for all scenarios including the new default behavior."""
+    import datajoint as dj
+
+    AnalysisNwbfile = common.AnalysisNwbfile
+    Nwbfile = common.Nwbfile
+
+    # Test table with explicit _nwb_table attribute
+    class TableWithNwbTableAttr(SpyglassMixin, dj.Lookup):
+        definition = """
+        id : int
+        """
+        _nwb_table = common.AnalysisNwbfile
+        contents = [(0,)]
+
+    schema_test(TableWithNwbTableAttr)
+    table, attr = TableWithNwbTableAttr()._nwb_table_tuple
+    assert table == common.AnalysisNwbfile, "Should use _nwb_table attribute"
+    assert attr == "analysis_file_abs_path", "Should use analysis file path"
+
+    # Test table with AnalysisNwbfile FK in definition
+    class TableWithAnalysisNwbfileFK(SpyglassMixin, dj.Lookup):
+        definition = """
+        -> AnalysisNwbfile
+        id : int
+        """
+        contents = []
+
+    schema_test(TableWithAnalysisNwbfileFK)
+    table, attr = TableWithAnalysisNwbfileFK()._nwb_table_tuple
+    assert table == common.AnalysisNwbfile, "Should detect AnalysisNwbfile FK"
+    assert attr == "analysis_file_abs_path", "Should use analysis file path"
+
+    # Test table with explicit Nwbfile FK in definition
+    class TableWithNwbfileFK(SpyglassMixin, dj.Lookup):
+        definition = """
+        -> Nwbfile
+        id : int
+        """
+        contents = []
+
+    schema_test(TableWithNwbfileFK)
+    table, attr = TableWithNwbfileFK()._nwb_table_tuple
+    assert table == common.Nwbfile, "Should detect Nwbfile FK"
+    assert attr == "nwb_file_abs_path", "Should use nwb file path"
+
+    # Test table with no FK reference (should default to Nwbfile)
+    class TableWithNoFK(SpyglassMixin, dj.Lookup):
+        definition = """
+        id : int
+        """
+        contents = [(0,)]
+
+    schema_test(TableWithNoFK)
+    table, attr = TableWithNoFK()._nwb_table_tuple
+    assert table == common.Nwbfile, "Should default to Nwbfile when no FK found"
+    assert attr == "nwb_file_abs_path", "Should use nwb file path by default"
+
+
+def test_nwb_table_precedence(schema_test, SpyglassMixin, common):
+    """Test that _nwb_table attribute takes precedence over FK definitions."""
+    import datajoint as dj
+
+    AnalysisNwbfile = common.AnalysisNwbfile
+
+    # _nwb_table should override FK in definition
+    class TableWithBoth(SpyglassMixin, dj.Lookup):
+        definition = """
+        -> AnalysisNwbfile
+        id : int
+        """
+        _nwb_table = common.Nwbfile  # Should override the FK
+        contents = []
+
+    schema_test(TableWithBoth)
+    table, attr = TableWithBoth()._nwb_table_tuple
+    assert table == common.Nwbfile, "_nwb_table should take precedence over FK"
+    assert (
+        attr == "nwb_file_abs_path"
+    ), "Should use nwb file path from _nwb_table"
 
 
 def test_auto_increment(schema_test, Mixin):