Update What's New

docs/whats_new.rst

@@ -3,6 +3,7 @@ What's New
 
 Discover notable new features and improvements in each release
 
+.. include::  whats_new/v0-7-4.rst
 .. include::  whats_new/v0-7-3.rst
 .. include::  whats_new/v0-7-2.rst
 .. include::  whats_new/v0-7-1.rst

docs/whats_new/v0-7-4.rst

@@ -0,0 +1,41 @@
+v0.7.4 - Newton's Nature (April, 30, 2024)
+++++++++++++++++++++++++++++++++++++++++++
+
+Bug Fixes
+#########
+- :code:`Component` and :code:`FluidWrapper` objects are now available for the
+  :code:`load_network` function via the :code:`@component_registry` and
+  :code:`@wrapper_registry` decorators. E.g. if you are using custom components
+  you can decorate them with the :code:`@component_registry` and the load a
+  :code:`Network` with those components without needing to adjust the source
+  code of the :code:`load_network` function
+  (`PR #510 <https://github.com/oemof/tespy/pull/510>`__).
+
+  .. code-block:: python
+
+      >>> from tespy.components.component import component_registry
+      >>> from tespy.components import Source, Sink, SimpleHeatExchanger
+      >>> from tespy.connections import Connection
+      >>> from tespy.networks import Network, load_network
+
+      >>> @component_registry
+      ... class MyComponent(SimpleHeatExchanger):
+      ...     pass
+
+      >>> c = component_registry.items["MyComponent"]("I am a component")
+      >>> c.label
+      'I am a component'
+
+      >>> nwk = Network()
+      >>> c1 = Connection(Source("source"), "out1", c, "in1", label="1")
+      >>> c2 = Connection(c, "out1", Sink("sink"), "in1", label="2")
+      >>> nwk.add_conns(c1, c2)
+      >>> nwk.export("exported_nwk")
+      >>> nwk = load_network("exported_nwk")
+      >>> nwk.comps.loc["I am a component", "comp_type"]
+      'MyComponent'
+
+Contributors
+############
+- Francesco Witte (`@fwitte <https://github.com/fwitte>`__)
+- `@jfreissmann <https://github.com/jfreissmann>`__

src/tespy/networks/network_reader.py

@@ -280,10 +280,11 @@ def _construct_components(target_class, data):
         for param, param_data in cp_data.items():
             container = instances[cp].get_attr(param)
             if isinstance(container, dc):
-                if isinstance(container, dc_cc):
-                    param_data["char_func"] = CharLine(**param_data["char_func"])
-                elif isinstance(container, dc_cm):
-                    param_data["char_func"] = CharMap(**param_data["char_func"])
+                if "char_func" in param_data:
+                    if isinstance(container, dc_cc):
+                        param_data["char_func"] = CharLine(**param_data["char_func"])
+                    elif isinstance(container, dc_cm):
+                        param_data["char_func"] = CharMap(**param_data["char_func"])
                 if isinstance(container, dc_prop):
                     param_data["val0"] = param_data["val"]
                 container.set_attr(**param_data)