Deprecate Inputs.connect and handle ambiguous connections (#2053)

* Propose fix to Inputs.connect() issue.

* Update tests

* Use warnings.warn(DeprecationWarning) as type_extensions is not in the DPF shipped Python

* Fix test to pass on master before sync

src/ansys/dpf/core/inputs.py

@@ -23,6 +23,7 @@
 """Inputs."""
 
 from textwrap import wrap
+import warnings
 import weakref
 
 from ansys.dpf import core
@@ -112,7 +113,7 @@ def connect(self, inpt):
             self._python_expected_types, inpt, self._pin, corresponding_pins
         )
         if len(corresponding_pins) > 1:
-            err_str = "Pin connection is ambiguous, specify the pin with:\n"
+            err_str = "Pin connection is ambiguous, specify the input to connect to with:\n"
             for pin in corresponding_pins:
                 err_str += (
                     "   - operator.inputs."
@@ -121,7 +122,9 @@ def connect(self, inpt):
                     + inpt._dict_outputs[pin[1]].name
                     + ")"
                 )
-            raise ValueError(err_str)
+            err_str += "Connecting to first input in the list.\n"
+            warnings.warn(message=err_str)
+            corresponding_pins = [corresponding_pins[0]]
 
         if len(corresponding_pins) == 0:
             err_str = (
@@ -218,13 +221,20 @@ def connect(self, inpt):
 
         Searches for the input type corresponding to the output.
 
+        .. deprecated::
+            Deprecated in favor of explicit output-to-input connections.
+
         Parameters
         ----------
         inpt : str, int, double, bool, list[int], list[float], Field, FieldsContainer, Scoping,
         ScopingsContainer, MeshedRegion, MeshesContainer, DataSources, CyclicSupport, Outputs, os.PathLike  # noqa: E501
             Input of the operator.
 
         """
+        warnings.warn(
+            message="Use explicit output-to-input connections.", category=DeprecationWarning
+        )
+
         from pathlib import Path
 
         corresponding_pins = []
@@ -250,12 +260,14 @@ def connect(self, inpt):
                 corresponding_pins,
             )
         if len(corresponding_pins) > 1:
-            err_str = "Pin connection is ambiguous, specify the pin with:\n"
+            err_str = "Pin connection is ambiguous, specify the input to connect to with:\n"
             for pin in corresponding_pins:
                 if isinstance(pin, tuple):
                     pin = pin[0]
                 err_str += "   - operator.inputs." + self._dict_inputs[pin].name + "(input)\n"
-            raise ValueError(err_str)
+            err_str += "Connecting to first input in the list.\n"
+            warnings.warn(message=err_str)
+            corresponding_pins = [corresponding_pins[0]]
 
         if len(corresponding_pins) == 0:
             err_str = "The input should have one of the expected types:\n"

tests/test_operator.py

@@ -556,7 +556,11 @@ def test_inputs_outputs_scopings_container(allkindofcomplexity):
     assert scop.location == dpf.core.locations.elemental
 
     stress = model.results.stress()
-    stress.inputs.connect(op.outputs)
+    with (
+        # pytest.warns(match="Pin connection is ambiguous"),
+        pytest.warns(DeprecationWarning, match="Use explicit"),
+    ):
+        stress.inputs.connect(op.outputs)
     fc = stress.outputs.fields_container()
     assert fc.labels == ["elshape", "time"]
     assert len(fc) == 4
@@ -589,8 +593,17 @@ def test_inputs_outputs_meshes_container(allkindofcomplexity):
     sc = opsc.outputs.mesh_scoping()
 
     stress = model.results.stress()
-    stress.inputs.connect(op.outputs)
-    stress.inputs.connect(opsc.outputs)
+    with (
+        # pytest.warns(match="Pin connection is ambiguous"),
+        pytest.warns(DeprecationWarning, match="Use explicit"),
+    ):
+        stress.inputs.connect(op.outputs)
+
+    with (
+        # pytest.warns(match="Pin connection is ambiguous"),
+        pytest.warns(DeprecationWarning, match="Use explicit"),
+    ):
+        stress.inputs.connect(opsc.outputs)
     fc = stress.outputs.fields_container()
     assert fc.labels == ["body", "elshape", "time"]
     assert len(fc) == 4