diff --git a/lib/galaxy/tool_util/parameters/convert.py b/lib/galaxy/tool_util/parameters/convert.py
index 94e4d0c5e569..63dbb9ab58b9 100644
--- a/lib/galaxy/tool_util/parameters/convert.py
+++ b/lib/galaxy/tool_util/parameters/convert.py
@@ -312,7 +312,6 @@ def _fill_default_for(tool_state: Dict[str, Any], parameter: ToolParameterT) ->
         )
         test_value = validate_explicit_conditional_test_value(test_parameter_name, explicit_test_value)
         when = _select_which_when(conditional, test_value, conditional_state)
-        test_parameter = conditional.test_parameter
         _fill_default_for(conditional_state, test_parameter)
         _fill_defaults(conditional_state, when)
     elif parameter_type in ["gx_repeat"]:
diff --git a/lib/galaxy/tool_util/parameters/factory.py b/lib/galaxy/tool_util/parameters/factory.py
index 8e99b7c95ba4..814f1ac6a9d7 100644
--- a/lib/galaxy/tool_util/parameters/factory.py
+++ b/lib/galaxy/tool_util/parameters/factory.py
@@ -282,7 +282,12 @@ def _from_input_source_galaxy(input_source: InputSource, profile: float) -> Tool
         default_test_value = cond_test_parameter_default_value(test_parameter)
         for value, case_inputs_sources in input_source.parse_when_input_sources():
             if isinstance(test_parameter, BooleanParameterModel):
-                # TODO: investigate truevalue/falsevalue when...
+                true_value = test_param_input_source.get("truevalue")
+                false_value = test_param_input_source.get("falsevalue")
+                if isinstance(value, str) and value == true_value:
+                    value = True
+                elif isinstance(value, str) and value == false_value:
+                    value = False
                 typed_value = string_as_bool(value)
             else:
                 typed_value = value
diff --git a/lib/galaxy/tool_util/parser/interface.py b/lib/galaxy/tool_util/parser/interface.py
index b9218ad54270..af72bf4a4825 100644
--- a/lib/galaxy/tool_util/parser/interface.py
+++ b/lib/galaxy/tool_util/parser/interface.py
@@ -435,6 +435,10 @@ def elem(self) -> Element:
         # used with other tool sources.
         raise NotImplementedError(NOT_IMPLEMENTED_MESSAGE)
 
+    @abstractmethod
+    def get_dynamic_options_code(self) -> Optional[str]:
+        """If dynamic options are a piece of code to eval, return it."""
+
     @abstractmethod
     def get_data_table_name(self) -> Optional[str]:
         """If dynamic options are loaded from a data table, return the name."""
diff --git a/lib/galaxy/tool_util/parser/xml.py b/lib/galaxy/tool_util/parser/xml.py
index 06a25c78f29b..a73378528d21 100644
--- a/lib/galaxy/tool_util/parser/xml.py
+++ b/lib/galaxy/tool_util/parser/xml.py
@@ -1300,12 +1300,17 @@ def parse_input_sources(self):
 
 class XmlDynamicOptions(DynamicOptions):
 
-    def __init__(self, options_elem: Element):
+    def __init__(self, options_elem: Element, dynamic_option_code: Optional[str]):
         self._options_elem = options_elem
+        self._dynamic_options_code = dynamic_option_code
 
     def elem(self) -> Element:
         return self._options_elem
 
+    def get_dynamic_options_code(self) -> Optional[str]:
+        """If dynamic options are a piece of code to eval, return it."""
+        return self._dynamic_options_code
+
     def get_data_table_name(self) -> Optional[str]:
         """If dynamic options are loaded from a data table, return the name."""
         return self._options_elem.get("from_data_table")
@@ -1349,7 +1354,12 @@ def parse_validators(self) -> List[AnyValidatorModel]:
     def parse_dynamic_options(self) -> Optional[XmlDynamicOptions]:
         """Return a XmlDynamicOptions to describe dynamic options if options elem is available."""
         options_elem = self.input_elem.find("options")
-        return XmlDynamicOptions(options_elem) if options_elem is not None else None
+        dynamic_option_code = self.input_elem.get("dynamic_options")
+        is_dynamic = options_elem is not None or dynamic_option_code is not None
+        if is_dynamic:
+            return XmlDynamicOptions(options_elem, dynamic_option_code)
+        else:
+            return None
 
     def parse_static_options(self) -> List[Tuple[str, str, bool]]:
         """
diff --git a/test/unit/app/tools/test_dynamic_options.py b/test/unit/app/tools/test_dynamic_options.py
index 77d9eb263ecf..05ec365a379e 100644
--- a/test/unit/app/tools/test_dynamic_options.py
+++ b/test/unit/app/tools/test_dynamic_options.py
@@ -6,9 +6,11 @@
 
 
 def get_from_url_option():
-    tool_param = Bunch()
-    tool_param.tool = Bunch()
-    tool_param.tool.app = Bunch()
+    tool_param = Bunch(
+        tool=Bunch(
+            app=Bunch(),
+        ),
+    )
 
     return DynamicOptions(
         XML(
diff --git a/test/unit/tool_util/test_parameter_convert.py b/test/unit/tool_util/test_parameter_convert.py
index a14eab6d5657..7f5deff41e85 100644
--- a/test/unit/tool_util/test_parameter_convert.py
+++ b/test/unit/tool_util/test_parameter_convert.py
@@ -217,6 +217,19 @@ def test_fill_defaults():
     assert with_defaults["cond"]["cond"] == "single"
     assert with_defaults["cond"]["inner_cond"]["inner_cond"] == "single"
 
+    # dynamic parameters should just stay empty - null would cause runtime to skip over population
+    with_defaults = fill_state_for({}, "parameters/gx_select_dynamic", partial=True)
+    assert "parameter" not in with_defaults
+
+    # dynamic parameters should just stay empty - null would cause runtime to skip over population
+    with_defaults = fill_state_for(
+        {"conditional_parameter": {"test_parameter": False}},
+        "parameters/gx_conditional_boolean_discriminate_on_string_value",
+    )
+    assert "conditional_parameter" in with_defaults
+    assert "boolean_parameter" in with_defaults["conditional_parameter"]
+    assert with_defaults["conditional_parameter"]["boolean_parameter"] is False
+
 
 def _fake_dereference(input: DataRequestUri) -> DataRequestInternalHda:
     return DataRequestInternalHda(id=EXAMPLE_ID_1)