Unexpected error: short SHA1 is ambiguous

In my copy of git.git:

$ git rev-list aabb^0 -- error: short SHA1 aabb is ambiguous. fatal: bad revision 'aabb'

$ git rev-list --all --objects | grep ^aabb aabb2e515c334cbca9d9ae9873a188cef2c9b3ba aabb9750fddbc28091c46780ccf7b835b62b04c7 Documentation/hooks.txt aabb1bcbe2b8ce00ced1a749cbab5c1646e0e1f2 Documentation

So a couple things:

1. Since I restricted to commits with ^0, and there's only one such
commit, shouldn't rev-list give me what I want? (rev-parse similarly
fails).

2. Shouldn't rev-list spit out whatever matches, even if it's
ambiguous? (I can understand that rev-parse wouldn't, but rev-list,
well, I expect a list of SHA1s from it.)

j.