Use of field flags in struct object

Hi,

The "flags" field in struct object (object.h) is used in a lot of places. The thing is, the bit definition of this field is distributed across files (16 according to my "object.flags |=" grep). This makes it quite easy for one function to misunderstand a bit set by another function, for a different purpose. For instance, in upload-pack.c, there is a comment:

/* bits #0..7 in revision.h, #8..10 in commit.c */

which is no longer true as commit.c has moved on and used another set of bits (16..19). Luckily, commit.c seems to clean its flags. But there's a chance we will get bit definition overlap again.

Should all of those bit definitions be gathered in one place instead?