Re: [PATCH 13/20] packed_object_info(): convert to new revindex API

On Tue, Jan 12, 2021 at 04:11:59AM -0500, Jeff King wrote:

quoted

  - Add an additional guard to check that the offset 'obj_offset()'
    points to a real object. This should be the case with well-behaved
    callers to 'packed_object_info()', but isn't guarenteed.

    Other blocks that fill in various other values from the 'struct
    object_info' request handle bad inputs by setting the type to
    'OBJ_BAD' and jumping to 'out'. Do the same when given a bad offset
    here.

Also good. I wonder if we need to call error() here, too. The caller
will probably say something like "bad object" or whatever, but the user
will have no clue that it's related to the revindex.

That would match other parts of the function (e.g., calling into
unpack_entry() can generate lots of descriptive errors about exactly
what went wrong).

Indeed, and we have the object's offset and pack name to include, too,
so our error can be quite descriptive.

Yep. Again, I'm really happy to see these "should never happen" cases
converted to real errors or even BUG()s.

:-).

Thanks,
Taylor