refactor(api): more clear error messages for type validation when cre…

…ating runtime parameters (#14903)

api/src/opentrons/protocols/parameters/validation.py

@@ -29,15 +29,21 @@ def validate_variable_name_unique(
 
 def ensure_display_name(display_name: str) -> str:
     """Validate display name is within the character limit."""
+    if not isinstance(display_name, str):
+        raise ParameterNameError(
+            f"Display name must be a string and at most {DISPLAY_NAME_MAX_LEN} characters."
+        )
     if len(display_name) > DISPLAY_NAME_MAX_LEN:
         raise ParameterNameError(
-            f"Display name {display_name} greater than {DISPLAY_NAME_MAX_LEN} characters."
+            f'Display name "{display_name}" greater than {DISPLAY_NAME_MAX_LEN} characters.'
         )
     return display_name
 
 
 def ensure_variable_name(variable_name: str) -> str:
     """Validate variable name is a valid python variable name."""
+    if not isinstance(variable_name, str):
+        raise ParameterNameError("Variable name must be a string.")
     if not variable_name.isidentifier():
         raise ParameterNameError(
             "Variable name must only contain alphanumeric characters, underscores, and cannot start with a digit."
@@ -49,19 +55,29 @@ def ensure_variable_name(variable_name: str) -> str:
 
 def ensure_description(description: Optional[str]) -> Optional[str]:
     """Validate description is within the character limit."""
-    if description is not None and len(description) > DESCRIPTION_MAX_LEN:
-        raise ParameterNameError(
-            f"Description {description} greater than {DESCRIPTION_MAX_LEN} characters."
-        )
+    if description is not None:
+        if not isinstance(description, str):
+            raise ParameterNameError(
+                f"Description must be a string and at most {DESCRIPTION_MAX_LEN} characters."
+            )
+        if len(description) > DESCRIPTION_MAX_LEN:
+            raise ParameterNameError(
+                f'Description "{description}" greater than {DESCRIPTION_MAX_LEN} characters.'
+            )
     return description
 
 
 def ensure_unit_string_length(unit: Optional[str]) -> Optional[str]:
     """Validate unit is within the character limit."""
-    if unit is not None and len(unit) > UNIT_MAX_LEN:
-        raise ParameterNameError(
-            f"Description {unit} greater than {UNIT_MAX_LEN} characters."
-        )
+    if unit is not None:
+        if not isinstance(unit, str):
+            raise ParameterNameError(
+                f"Unit must be a string and at most {UNIT_MAX_LEN} characters."
+            )
+        if len(unit) > UNIT_MAX_LEN:
+            raise ParameterNameError(
+                f'Unit "{unit}" greater than {UNIT_MAX_LEN} characters.'
+            )
     return unit
 
 
@@ -135,7 +151,7 @@ def convert_type_string_for_enum(
         return "str"
     else:
         raise ParameterValueError(
-            f"Cannot resolve parameter type {parameter_type} for an enumerated parameter."
+            f"Cannot resolve parameter type '{parameter_type.__name__}' for an enumerated parameter."
         )
 
 
@@ -147,7 +163,7 @@ def convert_type_string_for_num_param(parameter_type: type) -> Literal["int", "f
         return "float"
     else:
         raise ParameterValueError(
-            f"Cannot resolve parameter type {parameter_type} for a number parameter."
+            f"Cannot resolve parameter type '{parameter_type.__name__}' for a number parameter."
         )
 
 
@@ -173,7 +189,7 @@ def _validate_choices(
         ensure_display_name(display_name)
         if not isinstance(value, parameter_type):
             raise ParameterDefinitionError(
-                f"All choices provided must match type {type(parameter_type)}"
+                f"All choices provided must be of type '{parameter_type.__name__}'"
             )
 
 
@@ -192,29 +208,36 @@ def _validate_min_and_max(
             "If a maximum value is provided a minimum must also be provided."
         )
     elif maximum is not None and minimum is not None:
-        if isinstance(maximum, (int, float)) and isinstance(minimum, (int, float)):
-            if maximum <= minimum:
+        if parameter_type is int or parameter_type is float:
+            if not isinstance(minimum, parameter_type):
                 raise ParameterDefinitionError(
-                    "Maximum must be greater than the minimum"
+                    f"Minimum is type '{type(minimum).__name__}',"
+                    f" but must be of parameter type '{parameter_type.__name__}'"
                 )
-
-            if not isinstance(minimum, parameter_type) or not isinstance(
-                maximum, parameter_type
-            ):
+            if not isinstance(maximum, parameter_type):
                 raise ParameterDefinitionError(
-                    f"Minimum and maximum must match type {parameter_type}"
+                    f"Maximum is type '{type(maximum).__name__}',"
+                    f" but must be of parameter type '{parameter_type.__name__}'"
+                )
+            # These asserts are for the type checker and should never actually be asserted false
+            assert isinstance(minimum, (int, float))
+            assert isinstance(maximum, (int, float))
+            if maximum <= minimum:
+                raise ParameterDefinitionError(
+                    "Maximum must be greater than the minimum"
                 )
         else:
             raise ParameterDefinitionError(
-                "Only parameters of type float or int can have a minimum and maximum"
+                "Only parameters of type float or int can have a minimum and maximum."
             )
 
 
 def validate_type(value: ParamType, parameter_type: type) -> None:
     """Validate parameter value is the correct type."""
     if not isinstance(value, parameter_type):
         raise ParameterValueError(
-            f"Parameter value {value} has type {type(value)}, must match type {parameter_type}."
+            f"Parameter value {value} has type '{type(value).__name__}',"
+            f" but must be of type '{parameter_type.__name__}'."
         )
 
 
@@ -226,7 +249,11 @@ def validate_options(
     parameter_type: type,
 ) -> None:
     """Validate default values and all possible constraints for a valid parameter definition."""
-    validate_type(default, parameter_type)
+    if not isinstance(default, parameter_type):
+        raise ParameterValueError(
+            f"Parameter default {default} has type '{type(default).__name__}',"
+            f" but must be of type '{parameter_type.__name__}'."
+        )
 
     if choices is None and minimum is None and maximum is None:
         raise ParameterDefinitionError(

api/tests/opentrons/protocols/parameters/test_validation.py

@@ -278,14 +278,15 @@ def test_convert_type_string_for_num_param_raises(param_type: type) -> None:
             None,
             [{"display_name": "abc", "value": "123"}],
             int,
-            "must match type",
+            "must be of type",
         ),
         (123, 1, None, None, int, "maximum must also"),
         (123, None, 100, None, int, "minimum must also"),
         (123, 100, 1, None, int, "Maximum must be greater"),
-        (123, 1.1, 100, None, int, "Minimum and maximum must match type"),
-        (123, 1, 100.5, None, int, "Minimum and maximum must match type"),
-        (123, "1", "100", None, int, "Only parameters of type float or int"),
+        (123, 1.1, 100, None, int, "Minimum is type"),
+        (123, 1, 100.5, None, int, "Maximum is type"),
+        (123.0, "1.0", 100.0, None, float, "Minimum is type"),
+        ("blah", 1, 100, None, str, "Only parameters of type float or int"),
     ],
 )
 def test_validate_options_raise_definition_error(