restore dataclass_extensions. See #345

Author: cmungall

linkml_runtime/utils/dataclass_extensions_376.py

@@ -0,0 +1,30 @@
+import dataclasses
+#
+# The dataclass library builds a rigid `__init__` function that doesn't allow any unrecognized named parameters
+#
+# The purpose of this extension is to enhance the library to allow additional keyword arguments to passed in
+# and then on to the __post_init__ function that can deal with them accordingly
+
+# Beware that there is no promise that signature of the create function will remain consistent
+loc_fn = dataclasses._create_fn
+
+
+def dc_create_fn(name, args, body, *_posargs, **_kwargs):
+    # If overriding the initializer and using a post init
+    if name == '__init__' and dataclasses._POST_INIT_NAME in body[-1]:
+        # Then insert the kwargs into the both the call and the post init
+        pi_parms = body[-1].rsplit(')', 1)[0]
+        body[-1] = pi_parms + ('' if pi_parms[-1] == '(' else ',') + ' **_kwargs)'
+        return loc_fn(name, list(args) + ["**_kwargs"], body, *_posargs, **_kwargs)
+    else:
+        return loc_fn(name, args, body, *_posargs, **_kwargs)
+
+
+dataclasses._create_fn = dc_create_fn
+
+# The following line is here solely to be backwards compatible.
+dataclasses_init_fn_with_kwargs = dataclasses._init_fn
+
+# The following line can be used to make certain that the import of the new create function doesn't get
+# discarded as being potentially unused
+DC_CREATE_FN = True