Re: [PATCH 1/1] merge-recursive: remove unnecessary oid_eq function

"Elijah Newren via GitGitGadget" [off-list ref] writes:

From: Elijah Newren <redacted>

Back when merge-recursive was first introduced in commit 6d297f8137
(Status update on merge-recursive in C, 2006-07-08), it created a
sha_eq() function.  This function pre-dated the introduction of
hashcmp() to cache.h by about a month, but was switched over to using
hashcmp() as part of commit 9047ebbc22 (Split out merge_recursive() to
merge-recursive.c, 2008-08-12).  In commit b4da9d62f9 (merge-recursive:
convert leaf functions to use struct object_id, 2016-06-24), sha_eq() was
renamed to oid_eq() and its hashcmp() call was switched to oideq().

oid_eq() is basically just a wrapper around oideq() that has some extra
checks to protect against NULL arguments or to allow short-circuiting if
one of the arguments is NULL.  I don't know if any caller ever tried to
call with NULL arguments, but certainly none do now which means the
extra checks serve no purpose.  (Also, if these checks were genuinely
useful, then they probably should be added to the main oideq() so all
callers could benefit from them.)

Just for some historical yuck values ^W^W entertainment,
6d297f81373:merge-recursive.c shows how the function was called and
needed to prepare for NULL inputs.

I agree that today's code won't need the "two NULLs are equal, and NULL
is never equal to anything" hack.  We've come a long way ;-)