attr: drop DEBUG_ATTR code

Since its inception in d0bfd026a8 (Add basic infrastructure to assign
attributes to paths, 2007-04-12), the attribute code carries a little
bit of debug code that is conditionally compiled only when DEBUG_ATTR is
set. But since you have to know about it and make a special build of Git
to use it, it's not clear that it's helping anyone (and there are very
few mentions of it on the list over the years).

Meanwhile, it causes slight headaches. Since it's not built as part of a
regular compile, it's subject to bitrot. E.g., this was dealt with in
712efb1a42 (attr: make it build with DEBUG_ATTR again, 2013-01-15), and
it currently fails to build with DEVELOPER=1 since e810e06357 (attr:
tighten const correctness with git_attr and match_attr, 2017-01-27).

And it causes confusion with -Wunused-parameter; the "what" parameter of
fill_one() is unused in a normal build, but needed in a debug build.

Let's just get rid of this code (and the now-useless parameter).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

attr.c

@@ -23,10 +23,6 @@ static const char git_attr__unknown[] = "(builtin)unknown";
 #define ATTR__UNSET NULL
 #define ATTR__UNKNOWN git_attr__unknown
 
-#ifndef DEBUG_ATTR
-#define DEBUG_ATTR 0
-#endif
-
 struct git_attr {
 	int attr_nr; /* unique attribute number */
 	char name[FLEX_ARRAY]; /* attribute name */
@@ -807,33 +803,6 @@ static struct attr_stack *read_attr(struct index_state *istate,
 	return res;
 }
 
-#if DEBUG_ATTR
-static void debug_info(const char *what, struct attr_stack *elem)
-{
-	fprintf(stderr, "%s: %s\n", what, elem->origin ? elem->origin : "()");
-}
-static void debug_set(const char *what, const char *match, struct git_attr *attr, const void *v)
-{
-	const char *value = v;
-
-	if (ATTR_TRUE(value))
-		value = "set";
-	else if (ATTR_FALSE(value))
-		value = "unset";
-	else if (ATTR_UNSET(value))
-		value = "unspecified";
-
-	fprintf(stderr, "%s: %s => %s (%s)\n",
-		what, attr->name, (char *) value, match);
-}
-#define debug_push(a) debug_info("push", (a))
-#define debug_pop(a) debug_info("pop", (a))
-#else
-#define debug_push(a) do { ; } while (0)
-#define debug_pop(a) do { ; } while (0)
-#define debug_set(a,b,c,d) do { ; } while (0)
-#endif /* DEBUG_ATTR */
-
 static const char *git_etc_gitattributes(void)
 {
 	static const char *system_wide;
@@ -954,7 +923,6 @@ static void prepare_attr_stack(struct index_state *istate,
 		    (!namelen || path[namelen] == '/'))
 			break;
 
-		debug_pop(elem);
 		*stack = elem->prev;
 		attr_stack_free(elem);
 	}
@@ -1028,7 +996,7 @@ static int path_matches(const char *pathname, int pathlen,
 
 static int macroexpand_one(struct all_attrs_item *all_attrs, int nr, int rem);
 
-static int fill_one(const char *what, struct all_attrs_item *all_attrs,
+static int fill_one(struct all_attrs_item *all_attrs,
 		    const struct match_attr *a, int rem)
 {
 	int i;
@@ -1039,9 +1007,6 @@ static int fill_one(const char *what, struct all_attrs_item *all_attrs,
 		const char *v = a->state[i].setto;
 
 		if (*n == ATTR__UNKNOWN) {
-			debug_set(what,
-				  a->is_macro ? a->u.attr->name : a->u.pat.pattern,
-				  attr, v);
 			*n = v;
 			rem--;
 			rem = macroexpand_one(all_attrs, attr->attr_nr, rem);
@@ -1064,7 +1029,7 @@ static int fill(const char *path, int pathlen, int basename_offset,
 				continue;
 			if (path_matches(path, pathlen, basename_offset,
 					 &a->u.pat, base, stack->originlen))
-				rem = fill_one("fill", all_attrs, a, rem);
+				rem = fill_one(all_attrs, a, rem);
 		}
 	}
 
@@ -1076,7 +1041,7 @@ static int macroexpand_one(struct all_attrs_item *all_attrs, int nr, int rem)
 	const struct all_attrs_item *item = &all_attrs[nr];
 
 	if (item->macro && item->value == ATTR__TRUE)
-		return fill_one("expand", all_attrs, item->macro, rem);
+		return fill_one(all_attrs, item->macro, rem);
 	else
 		return rem;
 }