Re: [PATCH 01/12] vcs-svn: use higher mark numbers for blobs

Jonathan Nieder [off-list ref] writes:

Date: Fri, 10 Dec 2010 04:21:35 -0600

Prepare to use mark :5 for the commit corresponding to r5 (and so on).

1 billion seems sufficiently high for blob marks to avoid conflicting
with rev marks, while still leaving room for 3 billion blobs.  Such
high mark numbers cause trouble with ancient fast-import versions, but
this topic cannot support git fast-import versions before 1.7.4 (which
introduces the cat-blob command) anyway.

Hmm, 1G+3G split?  Will we have HIGHMEM option someday? ;-)

How confident are you that you will never need more than two classes later
and you will never need to split the larger space again?

If you are not, and if the topic is to introduce incompatible output,
would it be wiser to be even more forward looking and introduce different
classes of marks with a backward incompatible syntax, perhaps like using
":\d+" for anything, and using ":[a-zA-Z0-9]+:\d+" for some application
specific "class" of objects that is specifed by the [a-zA-Z0-9]+ part?