setup_gauges in wflow.py throws error when gauges_fn = None

[pauwiersma]

According to the documentation the default value of gauges_fn is None (line 1079), but os.path.isfile() throws an error if it is fed with a None (line 1119):

2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.gauges_fn: None
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.index_col: None
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.snap_to_river: False
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.mask: None
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.snap_uparea: False
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.max_dist: 10000.0
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.wdw: 3
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.rel_error: 0.05
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.derive_subcatch: False
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.basename: None
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.toml_output: csv
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.gauge_toml_header: ['Q', 'P']
2023-08-18 13:54:01,154 - build - model_api - INFO - setup_gauges.gauge_toml_param: ['lateral.river.q_av', 'vertical.precipitation']
2023-08-18 13:54:01,154 - build - main - ERROR - stat: path should be string, bytes, os.PathLike or integer, not NoneType
Traceback (most recent call last):
File "/home/pwiersma/miniconda3/envs/hydromt-wflow/lib/python3.10/site-packages/hydromt/cli/main.py", line 207, in build
mod.build(region, opt=opt)
File "/home/pwiersma/miniconda3/envs/hydromt-wflow/lib/python3.10/site-packages/hydromt/models/model_api.py", line 220, in build
self._run_log_method(method, **kwargs)
File "/home/pwiersma/miniconda3/envs/hydromt-wflow/lib/python3.10/site-packages/hydromt/models/model_api.py", line 163, in _run_log_method
return func(*args, **kwargs)
File "/home/pwiersma/miniconda3/envs/hydromt-wflow/lib/python3.10/site-packages/hydromt_wflow/wflow.py", line 1119, in setup_gauges
elif isfile(gauges_fn):
File "/home/pwiersma/miniconda3/envs/hydromt-wflow/lib/python3.10/genericpath.py", line 30, in isfile
st = os.stat(path)
TypeError: stat: path should be string, bytes, os.PathLike or integer, not NoneType

[JoostBuitink]

Good spot! The docstring of that function is outdated. We decided to no longer support the None argument in the setup_gauges method. If you don't want to add gauges to your model, we thought it is better to just remove the [setup_gauges] block from the ini file. We will update the docstring of this function to reflect this new behavior. Thanks for spotting this issue!