attr: do not mark queried macros as unset

peff · gitster · commit 7b95849be424 · 2019-01-22T13:48:15.000-08:00
Since 60a1272 (attr: remove maybe-real, maybe-macro from git_attr, 2017-01-27), we will always mark an attribute macro (e.g., "binary") that is specifically queried for as "unspecified", even though listing _all_ attributes would display it at set. E.g.: $ echo "* binary" >.gitattributes $ git check-attr -a file file: binary: set file: diff: unset file: merge: unset file: text: unset $ git check-attr binary file file: binary: unspecified The problem stems from an incorrect conversion of the optimization from 06a604e (attr: avoid heavy work when we know the specified attr is not defined, 2014-12-28). There we tried in collect_some_attrs() to avoid even looking at the attr_stack when the user has asked for "foo" and we know that "foo" did not ever appear in any .gitattributes file. It used a flag "maybe_real" in each attribute struct, where "real" meant that the attribute appeared in an actual file (we have to make this distinction because we also create an attribute struct for any names that are being queried). But as explained in that commit message, the meaning of "real" was tangled with some special cases around macros. When 60a1272 later refactored the macro code, it dropped maybe_real entirely. This missed the fact that "maybe_real" could be unset for two reasons: because of a macro, or because it was never found during parsing. This had two results: - the optimization in collect_some_attrs() ceased doing anything meaningful, since it no longer kept track of "was it found during parsing" - worse, it actually kicked in when the caller _did_ ask about a macro by name, causing us to mark it as unspecified It should be possible to salvage this optimization, but let's start with just removing the remnants. It hasn't been doing anything (except creating bugs) since 60a1272, and nobody seems to have noticed the performance regression. It's more important to fix the correctness problem clearly first. I've added two tests here. The second one actually shows off the bug. The test of "check-attr -a" is not strictly necessary, but we currently do not test attribute macros much, and the builtin "binary" not at all. So this increases our general test coverage, as well as making sure we didn't mess up this related case. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/attr.c b/attr.c
@@ -1104,7 +1104,7 @@ static void collect_some_attrs(const struct index_state *istate,
 			       const char *path,
 			       struct attr_check *check)
 {
-	int i, pathlen, rem, dirlen;
+	int pathlen, rem, dirlen;
 	const char *cp, *last_slash = NULL;
 	int basename_offset;
 
@@ -1125,20 +1125,6 @@ static void collect_some_attrs(const struct index_state *istate,
 	all_attrs_init(&g_attr_hashmap, check);
 	determine_macros(check->all_attrs, check->stack);
 
-	if (check->nr) {
-		rem = 0;
-		for (i = 0; i < check->nr; i++) {
-			int n = check->items[i].attr->attr_nr;
-			struct all_attrs_item *item = &check->all_attrs[n];
-			if (item->macro) {
-				item->value = ATTR__UNSET;
-				rem++;
-			}
-		}
-		if (rem == check->nr)
-			return;
-	}
-
 	rem = check->all_attrs_nr;
 	fill(path, pathlen, basename_offset, check->stack, check->all_attrs, rem);
 }
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
@@ -322,4 +322,24 @@ test_expect_success 'bare repository: test info/attributes' '
 	)
 '
 
+test_expect_success 'binary macro expanded by -a' '
+	echo "file binary" >.gitattributes &&
+	cat >expect <<-\EOF &&
+	file: binary: set
+	file: diff: unset
+	file: merge: unset
+	file: text: unset
+	EOF
+	git check-attr -a file >actual &&
+	test_cmp expect actual
+'
+
+
+test_expect_success 'query binary macro directly' '
+	echo "file binary" >.gitattributes &&
+	echo file: binary: set >expect &&
+	git check-attr binary file >actual &&
+	test_cmp expect actual
+'
+
 test_done
