Issue #15610: The PyImport_ImportModuleEx macro now calls

PyImport_ImportModuleLevel() with a 'level' of 0 instead of -1 as the
latter is no longer a valid value.

Also added a versionchanged note for PyImport_ImportModuleLevel() just
in case people don't make the connection between changes to
__import__() and this C function.

Doc/c-api/import.rst

@@ -44,8 +44,7 @@ Importing Modules
    .. index:: builtin: __import__
 
    Import a module.  This is best described by referring to the built-in Python
-   function :func:`__import__`, as the standard :func:`__import__` function calls
-   this function directly.
+   function :func:`__import__`.
 
    The return value is a new reference to the imported module or top-level
    package, or *NULL* with an exception set on failure.  Like for
@@ -76,6 +75,9 @@ Importing Modules
    Similar to :c:func:`PyImport_ImportModuleLevelObject`, but the name is an
    UTF-8 encoded string instead of a Unicode object.
 
+   .. versionchanged:: 3.3
+         Negative values for **level** are no longer accepted.
+
 .. c:function:: PyObject* PyImport_Import(PyObject *name)
 
    This is a higher-level interface that calls the current "import hook

Doc/whatsnew/3.3.rst

@@ -1880,6 +1880,11 @@ Porting C code
 
 * :c:func:`PyImport_GetMagicNumber` now returns -1 upon failure.
 
+* As a negative value for the **level** argument to :func:`__import__` is no
+  longer valid, the same now holds for :c:func:`PyImport_ImportModuleLevel`.
+  This also means that the value of **level** used by
+  :c:func:`PyImport_ImportModuleEx` is now 0 instead of -1.
+
 
 Building C extensions
 ---------------------

Include/import.h

@@ -62,7 +62,7 @@ PyAPI_FUNC(PyObject *) PyImport_ImportModuleLevelObject(
     );
 
 #define PyImport_ImportModuleEx(n, g, l, f) \
-    PyImport_ImportModuleLevel(n, g, l, f, -1)
+    PyImport_ImportModuleLevel(n, g, l, f, 0)
 
 PyAPI_FUNC(PyObject *) PyImport_GetImporter(PyObject *path);
 PyAPI_FUNC(PyObject *) PyImport_Import(PyObject *name);

Misc/NEWS

@@ -237,6 +237,9 @@ Library
 C API
 -----
 
+- Issue #15610: PyImport_ImportModuleEx() now uses a 'level' of 0 instead of
+  -1.
+
 - Issues #15169, #14599: Strip out the C implementation of
   imp.source_from_cache() used by PyImport_ExecCodeModuleWithPathnames() and
   used the Python code instead. Leads to PyImport_ExecCodeModuleObject() to not