diff --git a/pdm/installers.py b/pdm/installers.py
index 1e4f2a4fb098ab84b4cf54368c1a9d6c8af9ea39..f594b2a02ff6a78d1615e2711777ac551b999a52 100644
--- a/pdm/installers.py
+++ b/pdm/installers.py
@@ -79,7 +79,7 @@ class Installer:
         paths = self.environment.get_paths()
         install_script = importlib.import_module(
             "pdm._editable_install"
-        ).__file__.strip("co")
+        ).__file__.rstrip("co")
         install_args = [
             self.environment.python_executable,
             "-u",
diff --git a/pdm/utils.py b/pdm/utils.py
index 8a4f3e9f309884f0b24ed86e4f87ad173111b921..01bc3f928f349e879a163acf8a98f47deebe8080 100644
--- a/pdm/utils.py
+++ b/pdm/utils.py
@@ -334,9 +334,7 @@ def get_python_version(executable: str) -> Tuple[Union[str, int], ...]:
 
 
 def get_pep508_environment(executable: str) -> Dict[str, Any]:
-    script = importlib.import_module("pdm.pep508").__file__
-    if script.endswith("pyc"):
-        script = script[:-1]
+    script = importlib.import_module("pdm.pep508").__file__.rstrip("co")
     args = [executable, script]
     return json.loads(subprocess.check_output(args))