Cleanup: delete yaml_load_safely (#11285)

Related #11206 (comment)

readthedocs/doc_builder/backends/mkdocs.py

@@ -63,7 +63,8 @@ def get_final_doctype(self):
             allow_symlinks=True,
             base_path=self.project_path,
         ) as fh:
-            config = yaml_load_safely(fh)
+            # Use ``.safe_load()`` since ``mkdocs.yml`` is an untrusted source.
+            config = yaml.safe_load(fh)
             use_directory_urls = config.get("use_directory_urls", True)
             return MKDOCS if use_directory_urls else MKDOCS_HTML
 
@@ -119,62 +120,3 @@ def build(self):
 class MkdocsHTML(BaseMkdocs):
     builder = "build"
     build_dir = "_readthedocs/html"
-
-
-class ProxyPythonName(yaml.YAMLObject):
-    def __init__(self, value):
-        self.value = value
-
-    def __eq__(self, other):
-        return self.value == other.value
-
-
-class SafeLoader(yaml.SafeLoader):  # pylint: disable=too-many-ancestors
-
-    """
-    Safe YAML loader.
-
-    This loader parses special ``!!python/name:`` tags without actually
-    importing or executing code. Every other special tag is ignored.
-
-    Borrowed from https://stackoverflow.com/a/57121993
-    Issue https://github.com/readthedocs/readthedocs.org/issues/7461
-    """
-
-    def ignore_unknown(self, node):  # pylint: disable=unused-argument
-        return None
-
-    def construct_python_name(self, suffix, node):  # pylint: disable=unused-argument
-        return ProxyPythonName(suffix)
-
-
-class SafeDumper(yaml.SafeDumper):
-
-    """
-    Safe YAML dumper.
-
-    This dumper allows to avoid losing values of special tags that
-    were parsed by our safe loader.
-    """
-
-    def represent_name(self, data):
-        return self.represent_scalar("tag:yaml.org,2002:python/name:" + data.value, "")
-
-
-SafeLoader.add_multi_constructor(
-    "tag:yaml.org,2002:python/name:", SafeLoader.construct_python_name
-)
-SafeLoader.add_constructor(None, SafeLoader.ignore_unknown)
-SafeDumper.add_representer(ProxyPythonName, SafeDumper.represent_name)
-
-
-def yaml_load_safely(content):
-    """
-    Uses ``SafeLoader`` loader to skip unknown tags.
-
-    When a YAML contains ``!!python/name:int`` it will store the ``int``
-    suffix temporarily to be able to re-dump it later. We need this to avoid
-    executing random code, but still support these YAML files without
-    information loss.
-    """
-    return yaml.load(content, Loader=SafeLoader)