Use custom exception to carry sha1 of the missing obj

ecbaldwin · ecbaldwin · commit 919022a9e7a4 · 2018-01-29T11:34:04.000-07:00
I need to be able to detect what object is missing so that I can go
ask the server for it and try again. One reason I tend to like
creating my own custom exceptions is that they can carry context
appropriate information about what went wrong. However, I can also see
that it is more work.
diff --git a/git/cmd.py b/git/cmd.py
@@ -147,6 +147,12 @@ def dict_to_slots_and__excluded_are_none(self, d, excluded=()):
                       else 0)
 
 
+class MissingObject(ValueError):
+    def __init__(self, sha1, *args, **kwargs):
+        super(MissingObject, self).__init__(*args, **kwargs)
+        self.sha1 = sha1
+
+
 class Git(LazyMixin):
 
     """
@@ -1023,7 +1029,7 @@ def _parse_object_header(self, header_line):
             if not tokens:
                 raise ValueError("SHA could not be resolved, git returned: %r" % (header_line.strip()))
             else:
-                raise ValueError("SHA %s could not be resolved, git returned: %r" % (tokens[0], header_line.strip()))
+                raise MissingObject(tokens[0], "SHA %s could not be resolved, git returned: %r" % (tokens[0], header_line.strip()))
             # END handle actual return value
         # END error handling
 
