Fix breaking changes with Erddapy >= v0.8.0

.github/workflows/pythontests.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         python-version: [3.6, 3.7, 3.8]
-        os: [ubuntu-latest, macos-latest]
+        os: [macos-latest]
 
     steps:
       - uses: actions/checkout@master

argopy/data_fetchers/erddap_data.py

@@ -24,8 +24,15 @@
 from argopy.stores import httpstore
 from argopy.plotters import open_dashboard
 
-from erddapy import ERDDAP
-from erddapy.utilities import parse_dates, quote_string_constraints
+# Load erddapy according to available version (breaking changes in v0.8.0)
+try:
+    from erddapy import ERDDAP
+    from erddapy.utilities import parse_dates, quote_string_constraints
+except:
+    # >= v0.8.0
+    from erddapy.erddapy import ERDDAP
+    from erddapy.erddapy import _quote_string_constraints as quote_string_constraints
+    from erddapy.erddapy import parse_dates
 
 
 access_points = ["wmo", "box"]

argopy/data_fetchers/erddap_index.py

@@ -19,8 +19,17 @@
 from argopy.utilities import load_dict, mapp_dict, format_oneline
 from argopy.stores import httpstore
 
-from erddapy import ERDDAP
-from erddapy.utilities import parse_dates, quote_string_constraints
+# from erddapy import ERDDAP
+# from erddapy.utilities import parse_dates, quote_string_constraints
+# Load erddapy according to available version (breaking changes in v0.8.0)
+try:
+    from erddapy import ERDDAP
+    from erddapy.utilities import parse_dates, quote_string_constraints
+except:
+    # >= v0.8.0
+    from erddapy.erddapy import ERDDAP
+    from erddapy.erddapy import _quote_string_constraints as quote_string_constraints
+    from erddapy.erddapy import parse_dates
 
 
 access_points = ['wmo', 'box']

argopy/xarray.py

@@ -214,13 +214,34 @@ def filter_data_mode(self, keep_error: bool = True, errors: str = 'raise'):
         #########
         # Sub-functions
         #########
+        def safe_where_eq(xds, key, value):
+            # xds.where(xds[key] == value, drop=True) is not safe to empty time variables, cf issue #64
+            try:
+                return xds.where(xds[key] == value, drop=True)
+            except ValueError as v:
+                if v.args[0] == ("zero-size array to reduction operation "
+                                 "minimum which has no identity"):
+                    # A bug in xarray will cause a ValueError if trying to
+                    # decode the times in a NetCDF file with length 0.
+                    # See:
+                    # https://github.com/pydata/xarray/issues/1329
+                    # https://github.com/euroargodev/argopy/issues/64
+                    # Here, we just need to return an empty array
+                    TIME = xds['TIME']
+                    xds = xds.drop_vars('TIME')
+                    xds = xds.where(xds[key] == value, drop=True)
+                    xds['TIME'] = xr.DataArray(np.arange(len(xds['N_POINTS'])), dims='N_POINTS',
+                                               attrs=TIME.attrs).astype(np.datetime64)
+                    xds = xds.set_coords('TIME')
+                    return xds
+
         def ds_split_datamode(xds):
             """ Create one dataset for each of the data_mode
 
                 Split full dataset into 3 datasets
             """
             # Real-time:
-            argo_r = ds.where(ds['DATA_MODE'] == 'R', drop=True)
+            argo_r = safe_where_eq(xds, 'DATA_MODE', 'R')
             for v in plist:
                 vname = v.upper() + '_ADJUSTED'
                 if vname in argo_r:
@@ -232,7 +253,7 @@ def ds_split_datamode(xds):
                 if vname in argo_r:
                     argo_r = argo_r.drop_vars(vname)
             # Real-time adjusted:
-            argo_a = ds.where(ds['DATA_MODE'] == 'A', drop=True)
+            argo_a = safe_where_eq(xds, 'DATA_MODE', 'A')
             for v in plist:
                 vname = v.upper()
                 if vname in argo_a:
@@ -241,7 +262,7 @@ def ds_split_datamode(xds):
                 if vname in argo_a:
                     argo_a = argo_a.drop_vars(vname)
             # Delayed mode:
-            argo_d = ds.where(ds['DATA_MODE'] == 'D', drop=True)
+            argo_d = safe_where_eq(xds, 'DATA_MODE', 'D')
             return argo_r, argo_a, argo_d
 
         def fill_adjusted_nan(ds, vname):
@@ -295,7 +316,9 @@ def new_arrays(argo_r, argo_a, argo_d, vname):
                 return ds
 
         # Define variables to filter:
-        possible_list = ['PRES', 'TEMP', 'PSAL',
+        possible_list = ['PRES',
+                         'TEMP',
+                         'PSAL',
                          'DOXY',
                          'CHLA',
                          'BBP532',