hook: set `HGPLAIN=1` for external hooks
External hooks will probably turn around and run hg commands, so this seems like
a reasonable convenience for people who miss it in the documentation.
There are no test changes because `printenv.py` filters out anything without a
"HG_" prefix. It wouldn't be a useful test anyway, because this is already
inherited from the test environment.
Differential Revision: https://phab.mercurial-scm.org/D9605
--- a/mercurial/hook.py Mon Dec 14 17:59:10 2020 -0500
+++ b/mercurial/hook.py Mon Dec 14 18:03:29 2020 -0500
@@ -157,6 +157,7 @@
env[b'HG_PENDING'] = repo.root
env[b'HG_HOOKTYPE'] = htype
env[b'HG_HOOKNAME'] = name
+ env[b'HGPLAIN'] = b'1'
for k, v in pycompat.iteritems(args):
# transaction changes can accumulate MBs of data, so skip it