using git without blobs in the object database

[Bryan Larsen <bryan.larsen@gmail.com>]

Use Case:  A large set of large binary files, geographically 
distributed.  Each location has some unique files, some identical files 
and some slightly modified files.

I want to use git to tell me what changed and when.  But I cannot afford 
to have it store the blobs in the object database, nor do I need to; 
knowing the signature of previous objects is good enough.

It seems to me that most operations should work without these objects, 
and that some people do so.  For instance, git-update-cache has a 
--cacheinfo option that facilitates this operation.

But not all commands work so well.  For instance, git-write-tree will 
fail if --cacheinfo was used to add a file.  This failure is caused by a 
call to check_valid_sha1().  It appears that this check is not strictly 
necessary, just very useful for normal operation.

Would a patch that added a flag "--disable-sha1-check" to git-write-tree 
be accepted?  I hope that's all I need to add, but I haven't completed 
my evaluation yet.

thanks,
Bryan