Pandas outputs warning when calling dataframe.append in flux_csv_parser._prepare_data_frame

Specifications

• Client Version: 1.36.0
• InfluxDB Version: 2.7

Code sample to reproduce problem

query_api.query_data_frame(query)

Expected behavior

The query should be executed without warnings.

Actual behavior

Pandas outputs a FutureWarning:

/usr/local/lib/python3.11/site-packages/influxdb_client/client/flux_csv_parser.py:256: FutureWarning:
The behavior of array concatenation with empty entries is deprecated. In a future version, this will no longer exclude empty items when determining the result dtype. To retain the old behavior, exclude the empty entries before the concat operation.

This is related to the this code snippet:

https://github.com/influxdata/influxdb-client-python/blob/aa6e5c4aad1aaf004195c175ebe424ac6040c2e3/influxdb_client/client/flux_csv_parser.py#L243C9-L256

Additional info

In the recent pandas version handling of concatenation of empty dataframes changed, see https://github.com/pandas-dev/pandas/issues/39122. This should be handled else wise to reflect the changes in pandas.

Start in influxdb_client/client/flux_csv_parser.py around lines 243-256, where query_data_frame builds the dataframe, and reproduce the warning with query_api.query_data_frame(query). Compare the behavior with the pandas concatenation change described in pandas issue 39122. Done means the query executes without the reported FutureWarning.