# HG changeset patch
# User Matt Harbison <matt_harbison@yahoo.com>
# Date 1606541104 18000
# Node ID bc1b4eb21da984067fe3966a6d3aec8f80cd0ec8
# Parent  3a3a510617e573d3ee8d9eee3c5189a551f5b8c4
helptext: document the mechanism for extensions to report a version

Differential Revision: https://phab.mercurial-scm.org/D9448

diff -r 3a3a510617e5 -r bc1b4eb21da9 mercurial/helptext/internals/extensions.txt
--- a/mercurial/helptext/internals/extensions.txt	Sat Nov 28 13:42:55 2020 +0100
+++ b/mercurial/helptext/internals/extensions.txt	Sat Nov 28 00:25:04 2020 -0500
@@ -322,6 +322,15 @@
 Older clients will print a warning that the extension requires a new version,
 instead of attempting to load it.
 
+The extension itself can be assigned a version value through one of two module
+attributes, and will be displayed in crash reports and  :hg:`version -v`::
+
+  * ``__version__`` is a plain value
+  * ``getversion`` is a no argument ``Callable`` that returns a value
+
+In both cases, the value must be either a byte string, or a list or tuple of
+numeric values which will be joined with ``.``.
+
 Wrap up: what belongs where?
 ============================