--- OLD/revision.c	Thu Jan  1 00:00:00 1970
+++ NEW/revision.c	Thu Jan  1 00:00:00 1970
@@ -1144,12 +1144,14 @@
 		revs->abbrev = 0;
 	} else if (!strcmp(arg, "--abbrev")) {
 		revs->abbrev = DEFAULT_ABBREV;
+		abbrev_length = DEFAULT_ABBREV;
 	} else if (!prefixcmp(arg, "--abbrev=")) {
 		revs->abbrev = strtoul(arg + 9, NULL, 10);
 		if (revs->abbrev < MINIMUM_ABBREV)
 			revs->abbrev = MINIMUM_ABBREV;
 		else if (revs->abbrev > 40)
 			revs->abbrev = 40;
+		abbrev_length = revs->abbrev;
 	} else if (!strcmp(arg, "--abbrev-commit")) {
 		revs->abbrev_commit = 1;
 	} else if (!strcmp(arg, "--full-diff")) {