for-each-ref: report broken references correctly
commit8afc493d115e35092be8de3a441317f175928ab5
authorMichael Haggerty <mhagger@alum.mit.edu>
Tue, 2 Jun 2015 15:57:26 +0000 (2 17:57 +0200)
committerJunio C Hamano <gitster@pobox.com>
Tue, 2 Jun 2015 20:09:16 +0000 (2 13:09 -0700)
tree572e705a1a0e74ad6e585e73e43b7b9f9193dfd5
parentc3e23dc117beae7e89e81aed28b0e082a14d672e
for-each-ref: report broken references correctly

If there is a loose reference file with invalid contents, "git
for-each-ref" incorrectly reports the problem as being a missing
object with name NULL_SHA1:

    $ echo '12345678' >.git/refs/heads/nonsense
    $ git for-each-ref
    fatal: missing object 0000000000000000000000000000000000000000 for refs/heads/nonsense

With an explicit "--format" string, it can even report that the
reference validly points at NULL_SHA1:

    $ git for-each-ref --format='%(objectname) %(refname)'
    0000000000000000000000000000000000000000 refs/heads/nonsense
    $ echo $?
    0

This has been broken since

    b7dd2d2 for-each-ref: Do not lookup objects when they will not be used (2009-05-27)

, which changed for-each-ref from using for_each_ref() to using
git_for_each_rawref() in order to avoid looking up the referred-to
objects unnecessarily. (When "git for-each-ref" is given a "--format"
string that doesn't include information about the pointed-to object,
it does not look up the object at all, which makes it considerably
faster. Iterating with DO_FOR_EACH_INCLUDE_BROKEN is essential to this
optimization because otherwise for_each_ref() would itself need to
check whether the object exists as part of its brokenness test.)

But for_each_rawref() includes broken references in the iteration, and
"git for-each-ref" doesn't itself reject references with REF_ISBROKEN.
The result is that broken references are processed *as if* they had
the value NULL_SHA1, which is the value stored in entries for broken
references.

Change "git for-each-ref" to emit warnings for references that are
REF_ISBROKEN but to otherwise skip them.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/for-each-ref.c
t/t6301-for-each-ref-errors.sh