Include the UM version as a field property when reading UM files

Changelog.rst

@@ -1,9 +1,10 @@
-
-version NEXTRELEASE
+version NEXTVERSION
 -------------------
 
 **2024-??-??**
 
+* Include the UM version as a field property when reading UM files
+  (https://github.com/NCAS-CMS/cf-python/issues/777)
 * Fix bug where `cf.example_fields` returned a `list`
   of Fields rather than a `Fieldlist`
   (https://github.com/NCAS-CMS/cf-python/issues/725)

cf/field.py

@@ -10479,9 +10479,9 @@ def convolution_filter(
                     new_bounds[0 : length - lower_offset, 1:] = old_bounds[
                         lower_offset:length, 1:
                     ]
-                    new_bounds[length - lower_offset : length, 1:] = (
-                        old_bounds[length - 1, 1:]
-                    )
+                    new_bounds[
+                        length - lower_offset : length, 1:
+                    ] = old_bounds[length - 1, 1:]
 
                 coord.set_bounds(self._Bounds(data=new_bounds))
 

cf/read_write/um/umread.py

@@ -1040,6 +1040,22 @@ def __init__(
             cf_properties["stash_code"] = str(stash)
             cf_properties["submodel"] = str(submodel)
 
+            # Convert the UM version to a string and provide it as a
+            # CF property. E.g. 405 -> '4.5', 606.3 -> '6.6.3', 1002
+            # -> '10.2'
+            #
+            # Note: We don't just do `divmod(self.um_version, 100)`
+            #       because if self.um_version has a fractional part
+            #       then it would likely get altered in the divmod
+            #       calculation.
+            a, b = divmod(int(self.um_version), 100)
+            fraction = str(self.um_version).split(".")[-1]
+            um = f"{a}.{b}"
+            if fraction != "0" and fraction != str(self.um_version):
+                um += f".{fraction}"
+
+            cf_properties["um_version"] = um
+
             # --------------------------------------------------------
             # Set the data and extra data
             # --------------------------------------------------------

cf/test/test_Data.py

@@ -2389,7 +2389,9 @@ def test_Data_BINARY_AND_UNARY_OPERATORS(self):
                 except Exception:
                     pass
                 else:
-                    self.assertTrue((x**d).all(), "{}**{}".format(x, repr(d)))
+                    self.assertTrue(
+                        (x**d).all(), "{}**{}".format(x, repr(d))
+                    )
 
                 self.assertTrue(
                     d.__truediv__(x).equals(

cf/test/test_pp.py

@@ -57,7 +57,7 @@ def test_PP_read_um(self):
         g = cf.read(self.ppextradata, um={"fmt": "pp"})[0]
         self.assertTrue(f.equals(g))
 
-        for vn in (4.5, 405, "4.5", None):
+        for vn in (4.5, 405, "4.5"):
             g = cf.read(self.ppextradata, um={"fmt": "pp", "version": vn})[0]
             self.assertTrue(f.equals(g))
 
@@ -138,6 +138,13 @@ def test_PP_extra_data(self):
         self.assertTrue(f.dimension_coordinate("time", default=False))
         self.assertTrue(f.auxiliary_coordinate("longitude", default=False))
 
+    def test_PP_um_version(self):
+        f = cf.read(self.ppfile)[0]
+        self.assertEqual(f.get_property("um_version"), "11.0")
+
+        f = cf.read(self.ppfile, um={"version": "6.6.3"})[0]
+        self.assertEqual(f.get_property("um_version"), "6.6.3")
+
 
 if __name__ == "__main__":
     print("Run date:", datetime.datetime.now())

cf/weights.py

@@ -1461,9 +1461,9 @@ def linear(
         else:
             # Bounds exist
             if methods:
-                weights[(da_key,)] = (
-                    f"linear {f.constructs.domain_axis_identity(da_key)}"
-                )
+                weights[
+                    (da_key,)
+                ] = f"linear {f.constructs.domain_axis_identity(da_key)}"
             else:
                 weights[(da_key,)] = dim.cellsize