fix(presets): treat non-mapping command frontmatter as empty

src/specify_cli/presets/_resolver.py

@@ -916,9 +916,12 @@ def _parse_fm_yaml(fm_block: str) -> dict:
                 else:
                     yaml_lines = []
                 try:
-                    return yaml.safe_load("\n".join(yaml_lines)) or {}
+                    parsed = yaml.safe_load("\n".join(yaml_lines)) or {}
                 except yaml.YAMLError:
                     return {}
+                # Valid YAML that is not a mapping is treated like invalid
+                # frontmatter, matching CommandRegistrar.parse_frontmatter.
+                return parsed if isinstance(parsed, dict) else {}
 
             top_fm = _parse_fm_yaml(top_frontmatter_text)
 

tests/specify_cli/presets/test_resolver.py

@@ -1096,6 +1096,53 @@ def test_resolve_content_nonexistent(self, project_dir):
         content = resolver.resolve_content("nonexistent")
         assert content is None
 
+    def test_resolve_content_non_mapping_command_frontmatter(
+        self, project_dir, temp_dir, valid_pack_data
+    ):
+        """Valid YAML that is not a mapping must not crash composition.
+
+        ``_parse_fm_yaml`` returned whatever ``yaml.safe_load`` produced, and the
+        caller then called ``.pop`` on it, so ``preset add`` surfaced a raw
+        ``AttributeError``. ``CommandRegistrar.parse_frontmatter`` already treats
+        a non-dict result as ``{}``; the resolver now agrees.
+        """
+        pack_data = {**valid_pack_data}
+        pack_data["preset"] = {
+            **valid_pack_data["preset"],
+            "id": "odd-frontmatter-pack",
+            "name": "Odd Frontmatter",
+        }
+        pack_data["provides"] = {
+            "templates": [
+                {
+                    "type": "command",
+                    "name": "speckit.demo",
+                    "file": "commands/speckit.demo.md",
+                    "strategy": "append",
+                }
+            ]
+        }
+        pack_dir = temp_dir / "odd-frontmatter-pack"
+        pack_dir.mkdir()
+        with open(pack_dir / "preset.yml", "w") as f:
+            yaml.dump(pack_data, f)
+        (pack_dir / "commands").mkdir()
+        (pack_dir / "commands" / "speckit.demo.md").write_text(
+            "---\njust a note\n---\nAPPENDED\n", encoding="utf-8"
+        )
+        core_command = project_dir / ".specify" / "templates" / "commands" / "speckit.demo.md"
+        core_command.parent.mkdir(parents=True, exist_ok=True)
+        core_command.write_text("---\ndescription: core\n---\nCORE BODY\n", encoding="utf-8")
+
+        PresetManager(project_dir).install_from_directory(pack_dir, "0.1.5")
+
+        content = PresetResolver(project_dir).resolve_content("speckit.demo", "command")
+
+        assert content is not None
+        assert "CORE BODY" in content
+        assert "APPENDED" in content
+        assert "just a note" not in content
+
     def test_resolve_content_unreadable_winning_layer_returns_none(self, project_dir):
         """An undecodable winning layer must yield None, not a raw traceback.