Use process function name and docstring as default label and description

The function name and docstring will be set as the default for the label
and description metadata inputs. If the docstring is not defined, or
specific defaults are defined, the defaults are not overridden.

aiida/backends/tests/engine/test_process_function.py

@@ -36,7 +36,7 @@ class TestProcessFunction(AiidaTestCase):
     function would complain as the dummy node class is not recognized as a valid process node.
     """
 
-    # pylint: disable=too-many-public-methods
+    # pylint: disable=too-many-public-methods,too-many-instance-attributes
 
     def setUp(self):
         super(TestProcessFunction, self).setUp()
@@ -86,6 +86,11 @@ def function_defaults(
                 }):  # pylint: disable=unused-argument,dangerous-default-value,missing-docstring
             return data_a
 
+        @workfunction
+        def function_default_from_docs():
+            """Description taken from the docs."""
+            return
+
         @workfunction
         def function_exit_code(exit_status, exit_message):
             return ExitCode(exit_status.value, exit_message.value)
@@ -107,6 +112,7 @@ def function_out_unstored():
         self.function_args_and_kwargs = function_args_and_kwargs
         self.function_args_and_default = function_args_and_default
         self.function_defaults = function_defaults
+        self.function_default_from_docs = function_default_from_docs
         self.function_exit_code = function_exit_code
         self.function_excepts = function_excepts
         self.function_out_unstored = function_out_unstored
@@ -300,6 +306,18 @@ def test_function_defaults(self):
         self.assertEqual(node.label, CUSTOM_LABEL)
         self.assertEqual(node.description, CUSTOM_DESCRIPTION)
 
+    def test_function_default_label_description(self):
+        """Verify unless specified label and description are taken from function name and docstring respectively."""
+        metadata = {'label': CUSTOM_LABEL, 'description': CUSTOM_DESCRIPTION}
+
+        _, node = self.function_default_from_docs.run_get_node()
+        self.assertEqual(node.label, 'function_default_from_docs')
+        self.assertEqual(node.description, 'Description taken from the docs.')
+
+        _, node = self.function_default_from_docs.run_get_node(metadata=metadata)
+        self.assertEqual(node.label, CUSTOM_LABEL)
+        self.assertEqual(node.description, CUSTOM_DESCRIPTION)
+
     def test_launchers(self):
         """Verify that the various launchers are working."""
         result = run(self.function_return_true)

aiida/engine/processes/functions.py

@@ -221,6 +221,16 @@ def _define(cls, spec):
 
                     spec.input(arg, valid_type=valid_type, default=default)
 
+            # Set defaults for label and description based on function name and docstring, if not explicitly defined
+            port_label = spec.inputs['metadata']['label']
+            port_description = spec.inputs['metadata']['description']
+
+            if not port_label.has_default():
+                port_label.default = func.__name__
+
+            if not port_description.has_default() and func.__doc__:
+                port_description.default = func.__doc__
+
             # If the function support kwargs then allow dynamic inputs, otherwise disallow
             spec.inputs.dynamic = keywords is not None