hgrc: introduce HGRCSKIPREPO to skip reading the repository's hgrc We had a way to change the behavior regarding reading the global and user config, but we had nothing regarding the repository hgrc itself. This option is useful in situation where scripts need to be able to work around strange configuration set by the user in his repository. (and were HGPLAIN is not enough). Differential Revision: https://phab.mercurial-scm.org/D7807

--- a/mercurial/localrepo.py	Sat Jan 18 10:37:14 2020 -0800
+++ b/mercurial/localrepo.py	Tue Jan 07 11:24:05 2020 +0100
@@ -676,6 +676,8 @@
     configs are loaded. For example, an extension may wish to pull in
     configs from alternate files or sources.
     """
+    if b'HGRCSKIPREPO' in encoding.environ:
+        return False
     try:
         ui.readconfig(hgvfs.join(b'hgrc'), root=wdirvfs.base)
         return True