lfs: clarify pointer validation error messages

It wasn't obvious that LFS was involved from the error messages when `hg verify`
fails.

hgext/lfs/pointer.py

@@ -1,81 +1,83 b''
 # pointer.py - Git-LFS pointer serialization
 #
 # Copyright 2017 Facebook, Inc.
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import re
 
 from mercurial.i18n import _
 
 from mercurial import (
     error,
     pycompat,
 )
 from mercurial.utils import (
     stringutil,
 )
 
 class InvalidPointer(error.RevlogError):
     pass
 
 class gitlfspointer(dict):
     VERSION = 'https://git-lfs.github.com/spec/v1'
 
     def __init__(self, *args, **kwargs):
         self['version'] = self.VERSION
         super(gitlfspointer, self).__init__(*args)
         self.update(pycompat.byteskwargs(kwargs))
 
     @classmethod
     def deserialize(cls, text):
         try:
             return cls(l.split(' ', 1) for l in text.splitlines()).validate()
         except ValueError: # l.split returns 1 item instead of 2
             raise InvalidPointer(_('cannot parse git-lfs text: %s')
                                  % stringutil.pprint(text))
 
     def serialize(self):
         sortkeyfunc = lambda x: (x[0] != 'version', x)
         items = sorted(self.validate().iteritems(), key=sortkeyfunc)
         return ''.join('%s %s\n' % (k, v) for k, v in items)
 
     def oid(self):
         return self['oid'].split(':')[-1]
 
     def size(self):
         return int(self['size'])
 
     # regular expressions used by _validate
     # see https://github.com/git-lfs/git-lfs/blob/master/docs/spec.md
     _keyre = re.compile(br'\A[a-z0-9.-]+\Z')
     _valuere = re.compile(br'\A[^\n]*\Z')
     _requiredre = {
         'size': re.compile(br'\A[0-9]+\Z'),
         'oid': re.compile(br'\Asha256:[0-9a-f]{64}\Z'),
         'version': re.compile(br'\A%s\Z' % re.escape(VERSION)),
     }
 
     def validate(self):
         """raise InvalidPointer on error. return self if there is no error"""
         requiredcount = 0
         for k, v in self.iteritems():
             if k in self._requiredre:
                 if not self._requiredre[k].match(v):
-                    raise InvalidPointer(_('unexpected value: %s=%s')
-                                         % (k, stringutil.pprint(v)))
+                    raise InvalidPointer(
+                        _('unexpected lfs pointer value: %s=%s')
+                        % (k, stringutil.pprint(v)))
                 requiredcount += 1
             elif not self._keyre.match(k):
-                raise InvalidPointer(_('unexpected key: %s') % k)
+                raise InvalidPointer(_('unexpected lfs pointer key: %s') % k)
             if not self._valuere.match(v):
-                raise InvalidPointer(_('unexpected value: %s=%s')
+                raise InvalidPointer(_('unexpected lfs pointer value: %s=%s')
                                      % (k, stringutil.pprint(v)))
         if len(self._requiredre) != requiredcount:
             miss = sorted(set(self._requiredre.keys()).difference(self.keys()))
-            raise InvalidPointer(_('missed keys: %s') % ', '.join(miss))
+            raise InvalidPointer(_('missing lfs pointer keys: %s')
+                                 % ', '.join(miss))
         return self
 
 deserialize = gitlfspointer.deserialize

tests/test-lfs-pointer.py.out

@@ -1,12 +1,12 b''
-missed keys: oid, size
+missing lfs pointer keys: oid, size
 ok
-unexpected value: version='https://unknown.github.com/spec/v1'
+unexpected lfs pointer value: version='https://unknown.github.com/spec/v1'
 cannot parse git-lfs text: 'version https://git-lfs.github.com/spec/v1\n\noid sha256:4d7a214614ab2935c943f9e0ff69d22eadbb8f32b1258daaa5e2ca24d17e2393\nsize 12345\nx-foo extra-information\n'
-unexpected value: oid='ahs256:4d7a214614ab2935c943f9e0ff69d22eadbb8f32b1258daaa5e2ca24d17e2393'
-unexpected value: oid='4d7a214614ab2935c943f9e0ff69d22eadbb8f32b1258daaa5e2ca24d17e2393'
-unexpected value: size='0x12345'
+unexpected lfs pointer value: oid='ahs256:4d7a214614ab2935c943f9e0ff69d22eadbb8f32b1258daaa5e2ca24d17e2393'
+unexpected lfs pointer value: oid='4d7a214614ab2935c943f9e0ff69d22eadbb8f32b1258daaa5e2ca24d17e2393'
+unexpected lfs pointer value: size='0x12345'
 ok
 cannot parse git-lfs text: 'version https://git-lfs.github.com/spec/v1\noid sha256:4d7a214614ab2935c943f9e0ff69d22eadbb8f32b1258daaa5e2ca24d17e2393\nsize 12345\nx-foo extra\ninformation\n'
-unexpected key: x_foo
-missed keys: oid
-missed keys: oid, size
+unexpected lfs pointer key: x_foo
+missing lfs pointer keys: oid
+missing lfs pointer keys: oid, size