[PATCH] Better error checking for external commands

[Michael Ellerman]

Hi Martin,

This just fixes a TODO you added to the external command stuff.

cheers

*** modified file 'bzrlib/commands.py'
--- bzrlib/commands.py 
+++ bzrlib/commands.py 
@@ -146,17 +146,24 @@
     def __init__(self, path):
         self.path = path
 
-        # TODO: If either of these fail, we should detect that and
-        # assume that path is not really a bzr plugin after all.
-
         pipe = os.popen('%s --bzr-usage' % path, 'r')
         self.takes_options = pipe.readline().split()
+
+        for opt in self.takes_options:
+            if not opt in OPTIONS:
+                bailout("Unknown option '%s' returned by external command %s"
+                    % (opt, path))
+
+        # TODO: Is there any way to check takes_args is valid here?
         self.takes_args = pipe.readline().split()
-        pipe.close()
+
+        if pipe.close() is not None:
+            bailout("Failed funning '%s --bzr-usage'" % path)
 
         pipe = os.popen('%s --bzr-help' % path, 'r')
         self.__doc__ = pipe.read()
-        pipe.close()
+        if pipe.close() is not None:
+            bailout("Failed funning '%s --bzr-help'" % path)
 
     def __call__(self, options, arguments):
         Command.__init__(self, options, arguments)