bpo-42955: Add sys.modules_names (GH-24238)

Add sys.module_names, containing the list of the standard library
module names.

2 files changed, 25 insertions, 1 deletions

diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 0f13adcf0e5..d536fc9322e 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -153,10 +153,12 @@ always available.
 
 .. data:: builtin_module_names
 
-   A tuple of strings giving the names of all modules that are compiled into this
+   A tuple of strings containing the names of all modules that are compiled into this
    Python interpreter.  (This information is not available in any other way ---
    ``modules.keys()`` only lists the imported modules.)
 
+   See also the :attr:`sys.module_names` list.
+
 
 .. function:: call_tracing(func, args)
 
@@ -1060,6 +1062,24 @@ always available.
         This is still called as a fallback if a :data:`meta_path` entry doesn't
         have a :meth:`~importlib.abc.MetaPathFinder.find_spec` method.
 
+.. data:: module_names
+
+   A frozenset of strings containing the names of standard library modules.
+
+   It is the same on all platforms. Modules which are not available on
+   some platforms and modules disabled at Python build are also listed.
+   All module kinds are listed: pure Python, built-in, frozen and extension
+   modules. Test modules are excluded.
+
+   For packages, only sub-packages are listed, not sub-modules. For example,
+   ``concurrent`` package and ``concurrent.futures`` sub-package are listed,
+   but not ``concurrent.futures.base`` sub-module.
+
+   See also the :attr:`sys.builtin_module_names` list.
+
+   .. versionchanged:: 3.10
+
+
 .. data:: modules
 
    This is a dictionary that maps module names to modules which have already been
diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
index d822dda09d2..a6c3fbbff91 100644
--- a/Doc/whatsnew/3.10.rst
+++ b/Doc/whatsnew/3.10.rst
@@ -396,6 +396,10 @@ Add :data:`sys.orig_argv` attribute: the list of the original command line
 arguments passed to the Python executable.
 (Contributed by Victor Stinner in :issue:`23427`.)
 
+Add :data:`sys.module_names`, containing the list of the standard library
+module names.
+(Contributed by Victor Stinner in :issue:`42955`.)
+
 threading
 ---------