prefer "hash mismatch" to "sha1 mismatch"

To future-proof ourselves against a change in the hash, let's use the
more generic "hash mismatch" to refer to integrity problems. Note that
we do advertise this exact string in git-fsck(1). However, the message
itself is marked for translation, meaning we do not expect it to be
machine-readable.

While we're touching that documentation, let's also update it for
grammar and clarity.

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

Documentation/git-fsck.txt

@@ -140,9 +140,9 @@ dangling <type> <object>::
 	The <type> object <object>, is present in the database but never
 	'directly' used. A dangling commit could be a root node.
 
-sha1 mismatch <object>::
-	The database has an object who's sha1 doesn't match the
-	database value.
+hash mismatch <object>::
+	The database has an object whose hash doesn't match the
+	object database value.
 	This indicates a serious data integrity problem.
 
 Environment Variables

object.c

@@ -263,7 +263,7 @@ struct object *parse_object(struct repository *r, const struct object_id *oid)
 	    (!obj && has_object_file(oid) &&
 	     oid_object_info(r, oid, NULL) == OBJ_BLOB)) {
 		if (check_object_signature(repl, NULL, 0, NULL) < 0) {
-			error(_("sha1 mismatch %s"), oid_to_hex(oid));
+			error(_("hash mismatch %s"), oid_to_hex(oid));
 			return NULL;
 		}
 		parse_blob_buffer(lookup_blob(r, oid), NULL, 0);
@@ -274,7 +274,7 @@ struct object *parse_object(struct repository *r, const struct object_id *oid)
 	if (buffer) {
 		if (check_object_signature(repl, buffer, size, type_name(type)) < 0) {
 			free(buffer);
-			error(_("sha1 mismatch %s"), oid_to_hex(repl));
+			error(_("hash mismatch %s"), oid_to_hex(repl));
 			return NULL;
 		}
 

sha1-file.c

@@ -2218,7 +2218,7 @@ static int check_stream_oid(git_zstream *stream,
 
 	the_hash_algo->final_fn(real_oid.hash, &c);
 	if (!oideq(expected_oid, &real_oid)) {
-		error(_("sha1 mismatch for %s (expected %s)"), path,
+		error(_("hash mismatch for %s (expected %s)"), path,
 		      oid_to_hex(expected_oid));
 		return -1;
 	}
@@ -2270,7 +2270,7 @@ int read_loose_object(const char *path,
 		}
 		if (check_object_signature(expected_oid, *contents,
 					 *size, type_name(*type))) {
-			error(_("sha1 mismatch for %s (expected %s)"), path,
+			error(_("hash mismatch for %s (expected %s)"), path,
 			      oid_to_hex(expected_oid));
 			free(*contents);
 			goto out;

t/t1450-fsck.sh

@@ -406,7 +406,7 @@ test_expect_success 'rev-list --verify-objects with bad sha1' '
 
 	test_might_fail git rev-list --verify-objects refs/heads/bogus >/dev/null 2>out &&
 	cat out &&
-	test_i18ngrep -q "error: sha1 mismatch 63ffffffffffffffffffffffffffffffffffffff" out
+	test_i18ngrep -q "error: hash mismatch 63ffffffffffffffffffffffffffffffffffffff" out
 '
 
 test_expect_success 'force fsck to ignore double author' '