[RFC] - url-safe base64 commit-id's

Is there any appetite for base64'd commit-id's, using the url-safe variant (e.g. RFC 4648 [1] with padding removed)?

And so this: 712bad335dfa9c410a83f9873614a19726acb3a8

Becomes this: cSutM136nEEKg_mHNhShlyass6g

Under the hood things cannot change (e.g., ".git/objects/71/") because file systems are not always case sensitive.

But for "git log" and "git show" output it would be nice. And helps with ambiguous commit id's too if you only want to specify a 7 character commit-id, since that encodes 42 bits instead of 28 bits. I've run into problems with maximum command length on windows (32767 chars) because I was specifying so many commit-ids on the command-line that I blew past that limit. This would help there, too.

Might be particularly helpful with the transition to a new hash. e.g., a 43 character Base64 id instead of a 64 character hex id.

- Sylvie

[1] - https://tools.ietf.org/html/rfc4648#page-7