Add cached version of os.path.isfile to avoid repetitive I/O

astroid/interpreter/_import/spec.py

@@ -21,7 +21,7 @@
 from typing import Any, Literal, NamedTuple, Protocol
 
 from astroid.const import PY310_PLUS
-from astroid.modutils import EXT_LIB_DIRS
+from astroid.modutils import EXT_LIB_DIRS, cached_os_path_isfile
 
 from . import util
 
@@ -167,7 +167,7 @@ def find_module(
             for suffix in suffixes:
                 package_file_name = "__init__" + suffix
                 file_path = os.path.join(package_directory, package_file_name)
-                if os.path.isfile(file_path):
+                if cached_os_path_isfile(file_path):
                     return ModuleSpec(
                         name=modname,
                         location=package_directory,
@@ -176,7 +176,7 @@ def find_module(
             for suffix, type_ in ImportlibFinder._SUFFIXES:
                 file_name = modname + suffix
                 file_path = os.path.join(entry, file_name)
-                if os.path.isfile(file_path):
+                if cached_os_path_isfile(file_path):
                     return ModuleSpec(name=modname, location=file_path, type=type_)
         return None
 

astroid/manager.py

@@ -24,6 +24,7 @@
     NoSourceFile,
     _cache_normalize_path_,
     _has_init,
+    cached_os_path_isfile,
     file_info_from_modpath,
     get_source_file,
     is_module_name_part_of_extension_package_whitelist,
@@ -471,6 +472,7 @@ def clear_cache(self) -> None:
             LookupMixIn.lookup,
             _cache_normalize_path_,
             _has_init,
+            cached_os_path_isfile,
             util.is_namespace,
             ObjectModel.attributes,
             ClassDef._metaclass_lookup_attribute,

astroid/modutils.py

@@ -604,6 +604,12 @@ def is_relative(modname: str, from_file: str) -> bool:
     )
 
 
+@lru_cache(maxsize=1024)
+def cached_os_path_isfile(path: str | os.PathLike) -> bool:
+    """A cached version of os.path.isfile that helps avoid repetitive I/O"""
+    return os.path.isfile(path)
+
+
 # internal only functions #####################################################