Extract method for replacing sys_path, and isolate realpath usage there.

Author: jaraco

Lib/pdb.py

@@ -183,13 +183,9 @@ class _ExecutableTarget:
 
 class _ScriptTarget(_ExecutableTarget):
     def __init__(self, target):
+        self._target = target
         self._check(target)
-        self._target = os.path.realpath(target)
-
-        # If PYTHONSAFEPATH (-P) is not set, sys.path[0] is the directory
-        # of pdb, and we should replace it with the directory of the script
-        if not sys.flags.safe_path:
-            sys.path[0] = os.path.dirname(self._target)
+        self._replace_sys_path(target)
 
     @staticmethod
     def _check(target):
@@ -203,6 +199,13 @@ def _check(target):
             print(f'Error: {target} is a directory')
             sys.exit(1)
 
+    @staticmethod
+    def _replace_sys_path(target):
+        # If PYTHONSAFEPATH (-P) is not set, sys.path[0] is the directory
+        # of pdb, so replace it with the directory of the script
+        if not sys.flags.safe_path:
+            sys.path[0] = os.path.dirname(os.path.realpath(target))
+
     def __repr__(self):
         return self._target