Don't permit users to run repo status in a mirror client

If a client was created with "repo init --mirror" then there are
no working directories present, and no files checked out.  Using
a command like "repo status" in this context makes no sense, and
actually throws back a Pytyon traceback at the console when the
underlying commands fail out.

We now tag commands with the MirrorSafeCommand type if they are
able to be executed within a mirror directory safely.  Using a
command in a mirror which lacks this base class results in a
useful error letting you know the command isn't supported.

Bug: REPO-14
Signed-off-by: Shawn O. Pearce <sop@google.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/subcmds/help.py b/subcmds/help.py
index 6e0238a0..a2814e11 100644
--- a/subcmds/help.py
+++ b/subcmds/help.py
@@ -17,9 +17,9 @@ import sys
 from formatter import AbstractFormatter, DumbWriter
 
 from color import Coloring
-from command import PagedCommand
+from command import PagedCommand, MirrorSafeCommand
 
-class Help(PagedCommand):
+class Help(PagedCommand, MirrorSafeCommand):
   common = False
   helpSummary = "Display detailed help on a command"
   helpUsage = """