[PATCH] scmutil: fix systemrcpath regression introduced in f5dd179bfa4a

[Wolfgang Treutterer]

Changeset f5dd179bfa4a (plan9: initial support for plan 9 from bell 
labs) broke mercurials configuration file lookup. hgrc files located 
relative to the installation root are no longer read.

If mercurial is installed e.g. in /usr/local/bin the regression can be 
verified in the output of the command "hg showconfig --debug":

read config from: /etc/mercurial/hgrc
read config from: /etc/mercurial/hgrc
read config from: /$HOME/.hgrc
...

The system-wide "/etc/mercurial/hgrc" shows up twice in the initial 
whereas the installation-dependent location 
"/usr/local/etc/mercurial/hgrc" is missing.

The reason is that hangeset f5dd179bfa4a introduced a 'root' path 
component to look for hgrc files, which is used both as an absolute path 
and a path relative to the <install-root>.
The latter one was broken since 'root' was set to an absolute location
and the subsequent os.path.join discarded the <install-root> path prefix.

This patch changes 'root' to a relative path, such that os.path.join 
works as expected. The "/" prefix for the system-wide location is added 
separately.

# HG changeset patch
# User wot
# Date 1334304488 -7200
# Node ID 4e18cfcb2533e2ad0b672a1a40e41cca6b3e8c98
# Parent  ee163a9cf37c5783b7707f3264e3be901255ce25
scmutil: fix systemrcpath regression introduced in f5dd179bfa4a

Changeset f5dd179bfa4a introduced a 'root' path component to look for
hgrc files, which is used both as an absolute path and a path relative
to the <install-root>.
The latter one was broken since 'root' was set to an absolute location
and the subsequent os.path.join discarded the <install-root> path prefix.

diff -r ee163a9cf37c -r 4e18cfcb2533 mercurial/scmutil.py
--- a/mercurial/scmutil.py      Tue Apr 10 16:53:29 2012 -0500
+++ b/mercurial/scmutil.py      Fri Apr 13 10:08:08 2012 +0200
@@ -437,14 +437,14 @@
      def systemrcpath():
          path = []
          if sys.platform == 'plan9':
-            root = '/lib/mercurial'
+            root = 'lib/mercurial'
          else:
-            root = '/etc/mercurial'
+            root = 'etc/mercurial'
          # old mod_python does not set sys.argv
          if len(getattr(sys, 'argv', [])) > 0:
              p = os.path.dirname(os.path.dirname(sys.argv[0]))
              path.extend(rcfiles(os.path.join(p, root)))
-        path.extend(rcfiles(root))
+        path.extend(rcfiles('/' + root))
          return path

      def userrcpath():