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

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Elijah,

On Wed, 1 Jan 2020, Elijah Newren via GitGitGadget wrote:

> From: Elijah Newren <newren@gmail.com>
>
> 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.)
>
> Reduce the cognitive overhead of having both oid_eq() and oideq(), by
> getting rid of merge-recursive's special oid_eq() wrapper.
>
> Signed-off-by: Elijah Newren <newren@gmail.com>
> ---

The patch and the commit message look good to me!

Thanks,
Dscho

>  merge-recursive.c | 33 +++++++++++----------------------
>  1 file changed, 11 insertions(+), 22 deletions(-)
>
> diff --git a/merge-recursive.c b/merge-recursive.c
> index 11869ad81c..10dca5644b 100644
> --- a/merge-recursive.c
> +++ b/merge-recursive.c
> @@ -224,17 +224,6 @@ static struct commit *make_virtual_commit(struct repository *repo,
>  	return commit;
>  }
>
> -/*
> - * Since we use get_tree_entry(), which does not put the read object into
> - * the object pool, we cannot rely on a == b.
> - */
> -static int oid_eq(const struct object_id *a, const struct object_id *b)
> -{
> -	if (!a && !b)
> -		return 2;
> -	return a && b && oideq(a, b);
> -}
> -
>  enum rename_type {
>  	RENAME_NORMAL = 0,
>  	RENAME_VIA_DIR,
> @@ -805,7 +794,7 @@ static int was_tracked_and_matches(struct merge_options *opt, const char *path,
>
>  	/* See if the file we were tracking before matches */
>  	ce = opt->priv->orig_index.cache[pos];
> -	return (oid_eq(&ce->oid, &blob->oid) && ce->ce_mode == blob->mode);
> +	return (oideq(&ce->oid, &blob->oid) && ce->ce_mode == blob->mode);
>  }
>
>  /*
> @@ -1317,7 +1306,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
>  			oidcpy(&result->blob.oid, &b->oid);
>  		}
>  	} else {
> -		if (!oid_eq(&a->oid, &o->oid) && !oid_eq(&b->oid, &o->oid))
> +		if (!oideq(&a->oid, &o->oid) && !oideq(&b->oid, &o->oid))
>  			result->merge = 1;
>
>  		/*
> @@ -1333,9 +1322,9 @@ static int merge_mode_and_contents(struct merge_options *opt,
>  			}
>  		}
>
> -		if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &o->oid))
> +		if (oideq(&a->oid, &b->oid) || oideq(&a->oid, &o->oid))
>  			oidcpy(&result->blob.oid, &b->oid);
> -		else if (oid_eq(&b->oid, &o->oid))
> +		else if (oideq(&b->oid, &o->oid))
>  			oidcpy(&result->blob.oid, &a->oid);
>  		else if (S_ISREG(a->mode)) {
>  			mmbuffer_t result_buf;
> @@ -1368,7 +1357,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
>  			switch (opt->recursive_variant) {
>  			case MERGE_VARIANT_NORMAL:
>  				oidcpy(&result->blob.oid, &a->oid);
> -				if (!oid_eq(&a->oid, &b->oid))
> +				if (!oideq(&a->oid, &b->oid))
>  					result->clean = 0;
>  				break;
>  			case MERGE_VARIANT_OURS:
> @@ -2836,15 +2825,15 @@ static int process_renames(struct merge_options *opt,
>  			dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
>  			try_merge = 0;
>
> -			if (oid_eq(&src_other.oid, &null_oid) &&
> +			if (oideq(&src_other.oid, &null_oid) &&
>  			    ren1->dir_rename_original_type == 'A') {
>  				setup_rename_conflict_info(RENAME_VIA_DIR,
>  							   opt, ren1, NULL);
> -			} else if (oid_eq(&src_other.oid, &null_oid)) {
> +			} else if (oideq(&src_other.oid, &null_oid)) {
>  				setup_rename_conflict_info(RENAME_DELETE,
>  							   opt, ren1, NULL);
>  			} else if ((dst_other.mode == ren1->pair->two->mode) &&
> -				   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
> +				   oideq(&dst_other.oid, &ren1->pair->two->oid)) {
>  				/*
>  				 * Added file on the other side identical to
>  				 * the file being renamed: clean merge.
> @@ -2859,7 +2848,7 @@ static int process_renames(struct merge_options *opt,
>  						      1, /* update_cache */
>  						      0  /* update_wd    */))
>  					clean_merge = -1;
> -			} else if (!oid_eq(&dst_other.oid, &null_oid)) {
> +			} else if (!oideq(&dst_other.oid, &null_oid)) {
>  				/*
>  				 * Probably not a clean merge, but it's
>  				 * premature to set clean_merge to 0 here,
> @@ -3037,7 +3026,7 @@ static int blob_unchanged(struct merge_options *opt,
>
>  	if (a->mode != o->mode)
>  		return 0;
> -	if (oid_eq(&o->oid, &a->oid))
> +	if (oideq(&o->oid, &a->oid))
>  		return 1;
>  	if (!renormalize)
>  		return 0;
> @@ -3478,7 +3467,7 @@ static int merge_trees_internal(struct merge_options *opt,
>  					       opt->subtree_shift);
>  	}
>
> -	if (oid_eq(&merge_base->object.oid, &merge->object.oid)) {
> +	if (oideq(&merge_base->object.oid, &merge->object.oid)) {
>  		output(opt, 0, _("Already up to date!"));
>  		*result = head;
>  		return 1;
> --
> gitgitgadget
>