fix(rsc): preview error when displaying missing data

Author: machow

pins/boards.py

@@ -943,13 +943,21 @@ def prepare_pin_version(self, pin_dir_path, x, name: "str | None", *args, **kwar
 
         if isinstance(x, pd.DataFrame):
             # TODO(compat) is 100 hard-coded?
+            # Note that we go df -> json -> dict, to take advantage of pandas type conversions
             data = json.loads(x.head(100).to_json(orient="records"))
             columns = [
                 {"name": [col], "label": [col], "align": ["left"], "type": [""]}
                 for col in x
             ]
 
-            context["data_preview"] = json.dumps({"data": data, "columns": columns})
+            # this reproduces R pins behavior, by omitting entries that would be null
+            data_no_nulls = [
+                {k: v for k, v in row.items() if v is not None} for row in data
+            ]
+
+            context["data_preview"] = json.dumps(
+                {"data": data_no_nulls, "columns": columns}
+            )
         else:
             # TODO(compat): set display none in index.html
             context["data_preview"] = json.dumps({})

pins/tests/test_boards.py

@@ -100,7 +100,7 @@ def test_board_pin_write_rsc_index_html(board, tmp_dir2, snapshot):
     if board.fs.protocol != "rsc":
         pytest.skip()
 
-    df = pd.DataFrame({"x": [1, 2, 3], "y": ["a", "b", "c"]})
+    df = pd.DataFrame({"x": [1, 2, None], "y": ["a", "b", "c"]})
 
     pin_name = "test_rsc_pin"
 
@@ -113,6 +113,7 @@ def test_board_pin_write_rsc_index_html(board, tmp_dir2, snapshot):
         description="some description",
         created=DEFAULT_CREATION_DATE,
     )
+    assert False
 
     snapshot.assert_equal_dir(tmp_dir2)