Skip to content
  • Jeff King's avatar
    provide an initializer for "struct object_info" · 27b5c1a0
    Jeff King authored and Junio C Hamano's avatar Junio C Hamano committed
    An all-zero initializer is fine for this struct, but because
    the first element is a pointer, call sites need to know to
    use "NULL" instead of "0". Otherwise some static checkers
    like "sparse" will complain; see d099b717
    
     (Fix some sparse
    warnings, 2013-07-18) for example.  So let's provide an
    initializer to make this easier to get right.
    
    But let's also comment that memset() to zero is explicitly
    OK[1]. One of the callers embeds object_info in another
    struct which is initialized via memset (expand_data in
    builtin/cat-file.c). Since our subset of C doesn't allow
    assignment from a compound literal, handling this in any
    other way is awkward, so we'd like to keep the ability to
    initialize by memset(). By documenting this property, it
    should make anybody who wants to change the initializer
    think twice before doing so.
    
    There's one other caller of interest. In parse_sha1_header(),
    we did not initialize the struct fully in the first place.
    This turned out not to be a bug because the sub-function it
    calls does not look at any other fields except the ones we
    did initialize. But that assumption might not hold in the
    future, so it's a dangerous construct. This patch switches
    it to initializing the whole struct, which protects us
    against unexpected reads of the other fields.
    
    [1] Obviously using memset() to initialize a pointer
        violates the C standard, but we long ago decided that it
        was an acceptable tradeoff in the real world.
    
    Signed-off-by: default avatarJeff King <peff@peff.net>
    Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
    27b5c1a0