Verify input types for PrettyPrinter with a generator

sdb/command.py

@@ -634,24 +634,31 @@ def pretty_print(self, objs: Iterable[drgn.Object]) -> None:
         # pylint: disable=missing-docstring
         raise NotImplementedError
 
-    def _call(  # type: ignore[return]
-            self,
-            objs: Iterable[drgn.Object]) -> Optional[Iterable[drgn.Object]]:
+    def check_input_type(self,
+                         objs: Iterable[drgn.Object]) -> Iterable[drgn.Object]:
         """
-        This function will call pretty_print() on each input object,
-        verifying the types as we go.
+        This function acts as a generator, checking that each passed object
+        matches the input type for the command
         """
-
         assert self.input_type is not None
         type_name = type_canonicalize_name(self.input_type)
         for obj in objs:
             if type_canonical_name(obj.type_) != type_name:
                 raise CommandError(
                     self.name,
-                    f'exepected input of type {self.input_type}, but received '
+                    f'expected input of type {self.input_type}, but received '
                     f'type {obj.type_}')
+            yield obj
 
-            self.pretty_print([obj])
+    def _call(  # type: ignore[return]
+            self,
+            objs: Iterable[drgn.Object]) -> Optional[Iterable[drgn.Object]]:
+        """
+        This function will call pretty_print() on each input object,
+        verifying the types as we go.
+        """
+        assert self.input_type is not None
+        self.pretty_print(self.check_input_type(objs))
 
 
 class Locator(Command):

tests/integration/data/regression_output/core/spa | range_tree

@@ -0,0 +1 @@
+sdb: range_tree: expected input of type range_tree_t *, but received type spa_t *

tests/integration/test_core_generic.py

@@ -168,6 +168,9 @@
 
     # ptype - bogus type
     "ptype bogus_t",
+
+    # pretty printer passed incorrect type
+    "spa | range_tree"
 ]
 
 CMD_TABLE = POS_CMDS + NEG_CMDS