attr: Expand macros immediately when encountered.

When using macros it is otherwise hard to know whether an
attribute set by the macro should override an already set
attribute. Consider the following .gitattributes file:

[attr]mybinary	binary -ident
*		ident
foo.bin		mybinary
bar.bin		mybinary ident

Without this patch both foo.bin and bar.bin will have
the ident attribute set, which is probably not what
the user expects. With this patch foo.bin will have an
unset ident attribute, while bar.bin will have it set.

Signed-off-by: Henrik Grubbström <grubba@grubba.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: grubba

attr.c

@@ -594,6 +594,8 @@ static int path_matches(const char *pathname, int pathlen,
 	return fnmatch(pattern, pathname + baselen, FNM_PATHNAME) == 0;
 }
 
+static int macroexpand_one(int attr_nr, int rem);
+
 static int fill_one(const char *what, struct match_attr *a, int rem)
 {
 	struct git_attr_check *check = check_all_attr;
@@ -610,6 +612,7 @@ static int fill_one(const char *what, struct match_attr *a, int rem)
 				  attr, v);
 			*n = v;
 			rem--;
+			rem = macroexpand_one(attr->attr_nr, rem);
 		}
 	}
 	return rem;
@@ -631,19 +634,27 @@ static int fill(const char *path, int pathlen, struct attr_stack *stk, int rem)
 	return rem;
 }
 
-static int macroexpand(struct attr_stack *stk, int rem)
+static int macroexpand_one(int attr_nr, int rem)
 {
+	struct attr_stack *stk;
+	struct match_attr *a = NULL;
 	int i;
-	struct git_attr_check *check = check_all_attr;
 
-	for (i = stk->num_matches - 1; 0 < rem && 0 <= i; i--) {
-		struct match_attr *a = stk->attrs[i];
-		if (!a->is_macro)
-			continue;
-		if (check[a->u.attr->attr_nr].value != ATTR__TRUE)
-			continue;
+	if (check_all_attr[attr_nr].value != ATTR__TRUE)
+		return rem;
+
+	for (stk = attr_stack; !a && stk; stk = stk->prev)
+		for (i = stk->num_matches - 1; !a && 0 <= i; i--) {
+			struct match_attr *ma = stk->attrs[i];
+			if (!ma->is_macro)
+				continue;
+			if (ma->u.attr->attr_nr == attr_nr)
+				a = ma;
+		}
+
+	if (a)
 		rem = fill_one("expand", a, rem);
-	}
+
 	return rem;
 }
 
@@ -668,9 +679,6 @@ int git_checkattr(const char *path, int num, struct git_attr_check *check)
 	for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
 		rem = fill(path, pathlen, stk, rem);
 
-	for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
-		rem = macroexpand(stk, rem);
-
 	for (i = 0; i < num; i++) {
 		const char *value = check_all_attr[check[i].attr->attr_nr].value;
 		if (value == ATTR__UNKNOWN)

t/t0003-attributes.sh

@@ -20,10 +20,12 @@ test_expect_success 'setup' '
 
 	mkdir -p a/b/d a/c &&
 	(
+		echo "[attr]notest !test"
 		echo "f	test=f"
 		echo "a/i test=a/i"
 		echo "onoff test -test"
 		echo "offon -test test"
+		echo "no notest"
 	) >.gitattributes &&
 	(
 		echo "g test=a/g" &&
@@ -32,6 +34,7 @@ test_expect_success 'setup' '
 	(
 		echo "h test=a/b/h" &&
 		echo "d/* test=a/b/d/*"
+		echo "d/yes notest"
 	) >a/b/.gitattributes
 
 '
@@ -48,6 +51,9 @@ test_expect_success 'attribute test' '
 	attr_check a/b/d/g "a/b/d/*"
 	attr_check onoff unset
 	attr_check offon set
+	attr_check no unspecified
+	attr_check a/b/d/no "a/b/d/*"
+	attr_check a/b/d/yes unspecified
 
 '
 
@@ -64,6 +70,9 @@ a/b/h: test: a/b/h
 a/b/d/g: test: a/b/d/*
 onoff: test: unset
 offon: test: set
+no: test: unspecified
+a/b/d/no: test: a/b/d/*
+a/b/d/yes: test: unspecified
 EOF
 
 	sed -e "s/:.*//" < expect | git check-attr --stdin test > actual &&