Volshell: Attempt to resolve requirement conflicts

This change sets the `script`, `script-only`, and `primary` requirements
to only apply to the `generic.Volshell` class. `regex-scanner` is okay
to be shared between the base and inherited classes, but `script` and
`script-only` have to be generic-only in order to avoid conflicts when
populating the argparse parser.

`primary` must be generic-only in order to avoid ending up unsatisfied
when superclass requirements require a module, suppressing construction
of the `primary` layer.

volatility3/cli/volshell/generic.py

@@ -54,20 +54,24 @@ class Volshell(interfaces.plugins.PluginInterface):
 
     @classmethod
     def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]:
-        reqs: List[interfaces.configuration.RequirementInterface] = []
+        reqs: List[interfaces.configuration.RequirementInterface] = [
+            requirements.VersionRequirement(
+                name="regex_scanner",
+                component=scanners.RegExScanner,
+                version=(1, 0, 0),
+            ),
+        ]
         if cls == Volshell:
-            reqs = [
+            reqs += [
+                requirements.TranslationLayerRequirement(
+                    name="primary", description="Memory layer for the kernel"
+                ),
                 requirements.URIRequirement(
                     name="script",
                     description="File to load and execute at start",
                     default=None,
                     optional=True,
                 ),
-                requirements.VersionRequirement(
-                    name="regex_scanner",
-                    component=scanners.RegExScanner,
-                    version=(1, 0, 0),
-                ),
                 requirements.BooleanRequirement(
                     name="script-only",
                     description="Exit volshell after the script specified in --script completes",
@@ -75,11 +79,8 @@ class Volshell(interfaces.plugins.PluginInterface):
                     optional=True,
                 ),
             ]
-        return reqs + [
-            requirements.TranslationLayerRequirement(
-                name="primary", description="Memory layer for the kernel"
-            ),
-        ]
+
+        return reqs
 
     def run(
         self, additional_locals: Dict[str, Any] = {}