gh-95754: Better error when script shadows a standard library or third party module (#113769)

Doc/whatsnew/3.13.rst

@@ -104,6 +104,40 @@ Improved Error Messages
   variables. See also :ref:`using-on-controlling-color`.
   (Contributed by Pablo Galindo Salgado in :gh:`112730`.)
 
+* A common mistake is to write a script with the same name as a
+  standard library module. When this results in errors, we now
+  display a more helpful error message:
+
+  .. code-block:: shell-session
+
+    $ python random.py
+    Traceback (most recent call last):
+      File "/home/random.py", line 1, in <module>
+        import random; print(random.randint(5))
+        ^^^^^^^^^^^^^
+      File "/home/random.py", line 1, in <module>
+        import random; print(random.randint(5))
+                            ^^^^^^^^^^^^^^
+    AttributeError: module 'random' has no attribute 'randint' (consider renaming '/home/random.py' since it has the same name as the standard library module named 'random' and the import system gives it precedence)
+
+  Similarly, if a script has the same name as a third-party
+  module it attempts to import, and this results in errors,
+  we also display a more helpful error message:
+
+  .. code-block:: shell-session
+
+    $ python numpy.py
+    Traceback (most recent call last):
+      File "/home/numpy.py", line 1, in <module>
+        import numpy as np; np.array([1,2,3])
+        ^^^^^^^^^^^^^^^^^^
+      File "/home/numpy.py", line 1, in <module>
+        import numpy as np; np.array([1,2,3])
+                            ^^^^^^^^
+    AttributeError: module 'numpy' has no attribute 'array' (consider renaming '/home/numpy.py' if it has the same name as a third-party module you intended to import)
+
+  (Contributed by Shantanu Jain in :gh:`95754`.)
+
 * When an incorrect keyword argument is passed to a function, the error message
   now potentially suggests the correct keyword argument.
   (Contributed by Pablo Galindo Salgado and Shantanu Jain in :gh:`107944`.)