Merge branch 'js/maint-fetch-update-head' into maint

* js/maint-fetch-update-head:
  pull: allow "git pull origin $something:$current_branch" into an unborn branch
  Fix fetch/pull when run without --update-head-ok

Author: gitster

builtin-fetch.c

@@ -534,6 +534,19 @@ static void find_non_local_tags(struct transport *transport,
 	string_list_clear(&new_refs, 0);
 }
 
+static void check_not_current_branch(struct ref *ref_map)
+{
+	struct branch *current_branch = branch_get(NULL);
+
+	if (is_bare_repository() || !current_branch)
+		return;
+
+	for (; ref_map; ref_map = ref_map->next)
+		if (ref_map->peer_ref && !strcmp(current_branch->refname,
+					ref_map->peer_ref->name))
+			die("Refusing to fetch into current branch");
+}
+
 static int do_fetch(struct transport *transport,
 		    struct refspec *refs, int ref_count)
 {
@@ -558,6 +571,8 @@ static int do_fetch(struct transport *transport,
 	}
 
 	ref_map = get_ref_map(transport, refs, ref_count, tags, &autotags);
+	if (!update_head_ok)
+		check_not_current_branch(ref_map);
 
 	for (rm = ref_map; rm; rm = rm->next) {
 		if (rm->peer_ref)

git-pull.sh

@@ -124,7 +124,7 @@ orig_head=$(git rev-parse --verify HEAD 2>/dev/null)
 git fetch --update-head-ok "$@" || exit 1
 
 curr_head=$(git rev-parse --verify HEAD 2>/dev/null)
-if test "$curr_head" != "$orig_head"
+if test -n "$orig_head" && test "$curr_head" != "$orig_head"
 then
 	# The fetch involved updating the current branch.
 
@@ -172,7 +172,7 @@ esac
 
 if test -z "$orig_head"
 then
-	git update-ref -m "initial pull" HEAD $merge_head "" &&
+	git update-ref -m "initial pull" HEAD $merge_head "$curr_head" &&
 	git read-tree --reset -u HEAD || exit 1
 	exit
 fi

t/t5405-send-pack-rewind.sh

@@ -12,7 +12,7 @@ test_expect_success setup '
 	mkdir another && (
 		cd another &&
 		git init &&
-		git fetch .. master:master
+		git fetch --update-head-ok .. master:master
 	) &&
 
 	>file2 && git add file2 && test_tick &&

t/t5505-remote.sh

@@ -188,7 +188,7 @@ test_expect_success 'prune --dry-run' '
 test_expect_success 'add --mirror && prune' '
 	(mkdir mirror &&
 	 cd mirror &&
-	 git init &&
+	 git init --bare &&
 	 git remote add --mirror -f origin ../one) &&
 	(cd one &&
 	 git branch -m side2 side) &&

t/t5510-fetch.sh

@@ -303,4 +303,16 @@ test_expect_success 'pushing nonexistent branch by mistake should not segv' '
 
 '
 
+test_expect_success 'refuse to fetch into the current branch' '
+
+	test_must_fail git fetch . side:master
+
+'
+
+test_expect_success 'fetch into the current branch with --update-head-ok' '
+
+	git fetch --update-head-ok . side:master
+
+'
+
 test_done

t/t5520-pull.sh

@@ -29,6 +29,18 @@ test_expect_success 'checking the results' '
 	diff file cloned/file
 '
 
+test_expect_success 'pulling into void using master:master' '
+	mkdir cloned-uho &&
+	(
+		cd cloned-uho &&
+		git init &&
+		git pull .. master:master
+	) &&
+	test -f file &&
+	test -f cloned-uho/file &&
+	test_cmp file cloned-uho/file
+'
+
 test_expect_success 'test . as a remote' '
 
 	git branch copy master &&

t/t9300-fast-import.sh

@@ -983,7 +983,7 @@ test_expect_success \
 	 git checkout subuse1 &&
 	 rm -rf sub && mkdir sub && cd sub &&
 	 git init &&
-	 git fetch .. refs/heads/sub:refs/heads/master &&
+	 git fetch --update-head-ok .. refs/heads/sub:refs/heads/master &&
 	 git checkout master &&
 	 cd .. &&
 	 git submodule init &&