Merge branch 'jt/fetch-allow-tip-sha1-implicitly'

There is no good reason why "git fetch $there $sha1" should fail
when the $sha1 names an object at the tip of an advertised ref,
even when the other side hasn't enabled allowTipSHA1InWant.

* jt/fetch-allow-tip-sha1-implicitly:
  fetch-pack: always allow fetching of literal SHA1s

Author: gitster

fetch-pack.c

@@ -15,6 +15,7 @@
 #include "version.h"
 #include "prio-queue.h"
 #include "sha1-array.h"
+#include "oidset.h"
 
 static int transfer_unpack_limit = -1;
 static int fetch_unpack_limit = -1;
@@ -592,13 +593,38 @@ static void mark_recent_complete_commits(struct fetch_pack_args *args,
 	}
 }
 
+static void add_refs_to_oidset(struct oidset *oids, struct ref *refs)
+{
+	for (; refs; refs = refs->next)
+		oidset_insert(oids, &refs->old_oid);
+}
+
+static int tip_oids_contain(struct oidset *tip_oids,
+			    struct ref *unmatched, struct ref *newlist,
+			    const struct object_id *id)
+{
+	/*
+	 * Note that this only looks at the ref lists the first time it's
+	 * called. This works out in filter_refs() because even though it may
+	 * add to "newlist" between calls, the additions will always be for
+	 * oids that are already in the set.
+	 */
+	if (!tip_oids->map.tablesize) {
+		add_refs_to_oidset(tip_oids, unmatched);
+		add_refs_to_oidset(tip_oids, newlist);
+	}
+	return oidset_contains(tip_oids, id);
+}
+
 static void filter_refs(struct fetch_pack_args *args,
 			struct ref **refs,
 			struct ref **sought, int nr_sought)
 {
 	struct ref *newlist = NULL;
 	struct ref **newtail = &newlist;
+	struct ref *unmatched = NULL;
 	struct ref *ref, *next;
+	struct oidset tip_oids = OIDSET_INIT;
 	int i;
 
 	i = 0;
@@ -631,7 +657,8 @@ static void filter_refs(struct fetch_pack_args *args,
 			ref->next = NULL;
 			newtail = &ref->next;
 		} else {
-			free(ref);
+			ref->next = unmatched;
+			unmatched = ref;
 		}
 	}
 
@@ -649,14 +676,23 @@ static void filter_refs(struct fetch_pack_args *args,
 			continue;
 
 		if ((allow_unadvertised_object_request &
-		    (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1))) {
+		     (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1)) ||
+		    tip_oids_contain(&tip_oids, unmatched, newlist,
+				     &ref->old_oid)) {
 			ref->match_status = REF_MATCHED;
 			*newtail = copy_ref(ref);
 			newtail = &(*newtail)->next;
 		} else {
 			ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
 		}
 	}
+
+	oidset_clear(&tip_oids);
+	for (ref = unmatched; ref; ref = next) {
+		next = ref->next;
+		free(ref);
+	}
+
 	*refs = newlist;
 }
 

t/t5500-fetch-pack.sh

@@ -547,6 +547,41 @@ test_expect_success 'fetch-pack can fetch a raw sha1' '
 	git fetch-pack hidden $(git -C hidden rev-parse refs/hidden/one)
 '
 
+test_expect_success 'fetch-pack can fetch a raw sha1 that is advertised as a ref' '
+	rm -rf server client &&
+	git init server &&
+	test_commit -C server 1 &&
+
+	git init client &&
+	git -C client fetch-pack ../server \
+		$(git -C server rev-parse refs/heads/master)
+'
+
+test_expect_success 'fetch-pack can fetch a raw sha1 overlapping a named ref' '
+	rm -rf server client &&
+	git init server &&
+	test_commit -C server 1 &&
+	test_commit -C server 2 &&
+
+	git init client &&
+	git -C client fetch-pack ../server \
+		$(git -C server rev-parse refs/tags/1) refs/tags/1
+'
+
+test_expect_success 'fetch-pack cannot fetch a raw sha1 that is not advertised as a ref' '
+	rm -rf server &&
+
+	git init server &&
+	test_commit -C server 5 &&
+	git -C server tag -d 5 &&
+	test_commit -C server 6 &&
+
+	git init client &&
+	test_must_fail git -C client fetch-pack ../server \
+		$(git -C server rev-parse refs/heads/master^) 2>err &&
+	test_i18ngrep "Server does not allow request for unadvertised object" err
+'
+
 check_prot_path () {
 	cat >expected <<-EOF &&
 	Diag: url=$1