test: add escape for keys when serialize

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 1. [#198](https://github.com/InfluxCommunity/influxdb3-python/pull/198): Support custom tag order via `tag_order` write option.
    See [Sort tags by priority](https://docs.influxdata.com/influxdb3/enterprise/write-data/best-practices/schema-design/#sort-tags-by-query-priority) for more.
+1. [#202](https://github.com/InfluxCommunity/influxdb3-python/pull/202): Add escape for field keys when serializing to line protocol in `PolarsDataframeSerializer`.
 
 ## 0.18.0 [2026-02-19]
 

influxdb_client_3/write_client/client/write/polars_dataframe_serializer.py

@@ -92,12 +92,15 @@ def to_line_protocol(self, row):
         # add escape symbols for special characters to tags
 
         fields = ",".join(
-            f"{col}=\"{self.escape_value(row[self.column_indices[col]])}\"" if isinstance(row[self.column_indices[col]],
-                                                                                          str)
-            else f"{col}={str(row[self.column_indices[col]]).lower()}" if isinstance(row[self.column_indices[col]],
-                                                                                     bool)  # Check for bool first
-            else f"{col}={row[self.column_indices[col]]}i" if isinstance(row[self.column_indices[col]], int)
-            else f"{col}={row[self.column_indices[col]]}"
+            f"{self.escape_key(col)}=\"{self.escape_value(row[self.column_indices[col]])}\"" if isinstance(
+                row[self.column_indices[col]],
+                str)
+            else f"{self.escape_key(col)}={str(row[self.column_indices[col]]).lower()}" if isinstance(
+                row[self.column_indices[col]],
+                bool)  # Check for bool first
+            else f"{self.escape_key(col)}={row[self.column_indices[col]]}i" if isinstance(row[self.column_indices[col]],
+                                                                                          int)
+            else f"{self.escape_key(col)}={row[self.column_indices[col]]}"
             for col in self.column_indices
             if col not in self.tag_columns + [self.timestamp_column] and
             row[self.column_indices[col]] is not None and row[self.column_indices[col]] != ""

tests/test_polars.py

@@ -123,6 +123,30 @@ def test_to_list_of_points_with_precision_variants(self):
                 data_frame_measurement_name='iot-devices',
                 data_frame_timestamp_column='time')
 
+    def test_escape_for_key(self):
+        import polars as pl
+        ps = PointSettings(tag="prod")
+        df = pl.DataFrame(data={
+            "name whitespace": ['iot-devices'],
+            "tag1 whitespace": "something",
+            "building": ['5a'],
+            "temperature": [72.3],
+            "time": pl.Series(["2022-10-01T12:01:00Z"]).str.to_datetime(time_unit='ns')
+        })
+
+        actual = polars_data_frame_to_list_of_points(
+            data_frame=df, point_settings=ps,
+            data_frame_measurement_name='iot-devices',
+            data_frame_tag_columns=['building', 'tag1 whitespace'],
+            data_frame_timestamp_column='time',
+        )
+
+        expected = [
+            'iot-devices,building=5a,tag1\\ whitespace=something,tag=prod name\\ whitespace="iot-devices",'
+            'temperature=72.3 1664625660000000000'
+        ]
+        self.assertEqual(expected, actual)
+
 
 @unittest.skipIf(importlib.util.find_spec("polars") is None, 'Polars package not installed')
 class TestWritePolars(unittest.TestCase):