fix(bigtable): check family_name field presence in merge_rows

packages/google-cloud-bigtable/google/cloud/bigtable/data/_async/_read_rows.py

@@ -260,11 +260,11 @@ async def merge_rows(
                         if c.reset_row:
                             raise _ResetRow(c)
                         k = c.row_key
-                        f = c.family_name.value
+                        f = c.family_name.value if c.HasField("family_name") else None
                         q = c.qualifier.value if c.HasField("qualifier") else None
                         if k and k != row_key:
                             raise InvalidChunk("unexpected new row key")
-                        if f:
+                        if f is not None:
                             family = f
                             if q is not None:
                                 qualifier = q

packages/google-cloud-bigtable/google/cloud/bigtable/data/_sync_autogen/_read_rows.py

@@ -219,11 +219,11 @@ def merge_rows(
                         if c.reset_row:
                             raise _ResetRow(c)
                         k = c.row_key
-                        f = c.family_name.value
+                        f = c.family_name.value if c.HasField("family_name") else None
                         q = c.qualifier.value if c.HasField("qualifier") else None
                         if k and k != row_key:
                             raise InvalidChunk("unexpected new row key")
-                        if f:
+                        if f is not None:
                             family = f
                             if q is not None:
                                 qualifier = q

packages/google-cloud-bigtable/tests/unit/data/_async/test_read_rows_acceptance.py

@@ -263,6 +263,50 @@ async def test_missing_family(self):
                 )
             )
 
+    @CrossSync.pytest
+    async def test_empty_family_name_first_chunk(self):
+        rows = await self._process_chunks(
+            ReadRowsResponse.CellChunk(
+                row_key=b"a",
+                family_name="",
+                qualifier=b"q",
+                timestamp_micros=1000,
+                value=b"v",
+                commit_row=True,
+            )
+        )
+        assert len(rows) == 1
+        cells = rows[0].get_cells(family="", qualifier=b"q")
+        assert len(cells) == 1
+        assert cells[0].value == b"v"
+
+    @CrossSync.pytest
+    async def test_empty_family_name_after_nonempty_family(self):
+        rows = await self._process_chunks(
+            ReadRowsResponse.CellChunk(
+                row_key=b"a",
+                family_name="cf1",
+                qualifier=b"q",
+                timestamp_micros=2000,
+                value=b"v1",
+                commit_row=False,
+            ),
+            ReadRowsResponse.CellChunk(
+                family_name="",
+                qualifier=b"q",
+                timestamp_micros=1000,
+                value=b"v2",
+                commit_row=True,
+            ),
+        )
+        assert len(rows) == 1
+        cf1_cells = rows[0].get_cells(family="cf1", qualifier=b"q")
+        empty_cells = rows[0].get_cells(family="", qualifier=b"q")
+        assert len(cf1_cells) == 1
+        assert cf1_cells[0].value == b"v1"
+        assert len(empty_cells) == 1
+        assert empty_cells[0].value == b"v2"
+
     @CrossSync.pytest
     async def test_mid_cell_row_key_change(self):
         with pytest.raises(InvalidChunk):

packages/google-cloud-bigtable/tests/unit/data/_sync_autogen/test_read_rows_acceptance.py

@@ -250,6 +250,48 @@ def test_missing_family(self):
                 )
             )
 
+    def test_empty_family_name_first_chunk(self):
+        rows = self._process_chunks(
+            ReadRowsResponse.CellChunk(
+                row_key=b"a",
+                family_name="",
+                qualifier=b"q",
+                timestamp_micros=1000,
+                value=b"v",
+                commit_row=True,
+            )
+        )
+        assert len(rows) == 1
+        cells = rows[0].get_cells(family="", qualifier=b"q")
+        assert len(cells) == 1
+        assert cells[0].value == b"v"
+
+    def test_empty_family_name_after_nonempty_family(self):
+        rows = self._process_chunks(
+            ReadRowsResponse.CellChunk(
+                row_key=b"a",
+                family_name="cf1",
+                qualifier=b"q",
+                timestamp_micros=2000,
+                value=b"v1",
+                commit_row=False,
+            ),
+            ReadRowsResponse.CellChunk(
+                family_name="",
+                qualifier=b"q",
+                timestamp_micros=1000,
+                value=b"v2",
+                commit_row=True,
+            ),
+        )
+        assert len(rows) == 1
+        cf1_cells = rows[0].get_cells(family="cf1", qualifier=b"q")
+        empty_cells = rows[0].get_cells(family="", qualifier=b"q")
+        assert len(cf1_cells) == 1
+        assert cf1_cells[0].value == b"v1"
+        assert len(empty_cells) == 1
+        assert empty_cells[0].value == b"v2"
+
     def test_mid_cell_row_key_change(self):
         with pytest.raises(InvalidChunk):
             self._process_chunks(