bpo-32101: Add PYTHONDEVMODE environment variable (#4624)

* bpo-32101: Add sys.flags.dev_mode flag
  Rename also the "Developer mode" to the "Development mode".
* bpo-32101: Add PYTHONDEVMODE environment variable
  Mention it in the development chapiter.

1 files changed, 11 insertions, 1 deletions

diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst
index e6189fd812..d110ae3baf 100644
--- a/Doc/using/cmdline.rst
+++ b/Doc/using/cmdline.rst
@@ -411,7 +411,7 @@ Miscellaneous options
      nested imports).  Note that its output may be broken in multi-threaded
      application.  Typical usage is ``python3 -X importtime -c 'import
      asyncio'``.  See also :envvar:`PYTHONPROFILEIMPORTTIME`.
-   * ``-X dev``: enable CPython's "developer mode", introducing additional
+   * ``-X dev``: enable CPython's "development mode", introducing additional
      runtime checks which are too expensive to be enabled by default. It should
      not be more verbose than the default if the code is correct: new warnings
      are only emitted when an issue is detected. Effect of the developer mode:
@@ -426,6 +426,8 @@ Miscellaneous options
      * Enable the :mod:`faulthandler` module to dump the Python traceback
        on a crash.
      * Enable :ref:`asyncio debug mode <asyncio-debug-mode>`.
+     * Set the :attr:`~sys.flags.dev_mode` attribute of :attr:`sys.flags` to
+       ``True``
 
    It also allows passing arbitrary values and retrieving them through the
    :data:`sys._xoptions` dictionary.
@@ -796,6 +798,14 @@ conflict.
    .. versionadded:: 3.7
       See :pep:`538` for more details.
 
+
+.. envvar:: PYTHONDEVMODE
+
+   If this environment variable is set to a non-empty string, enable the
+   CPython "development mode". See the :option:`-X` ``dev`` option.
+
+   .. versionadded:: 3.7
+
 Debug-mode variables
 ~~~~~~~~~~~~~~~~~~~~