7 files changed, 105 insertions, 12 deletions

diff --git a/Documentation/gitremote-helpers.txt b/Documentation/gitremote-helpers.txt
index c2908db763..64f7ad26b4 100644
--- a/Documentation/gitremote-helpers.txt
+++ b/Documentation/gitremote-helpers.txt
@@ -437,6 +437,10 @@ set by Git if the remote helper has the 'option' capability.
 'option check-connectivity' \{'true'|'false'\}::
 	Request the helper to check connectivity of a clone.
 
+'option force' \{'true'|'false'\}::
+	Request the helper to perform a force update.  Defaults to
+	'false'.
+
 'option cloning \{'true'|'false'\}::
 	Notify the helper this is a clone request (i.e. the current
 	repository is guaranteed empty).
diff --git a/contrib/remote-helpers/git-remote-bzr b/contrib/remote-helpers/git-remote-bzr
index 332aba784b..5f4b2e3e16 100755
--- a/contrib/remote-helpers/git-remote-bzr
+++ b/contrib/remote-helpers/git-remote-bzr
@@ -684,7 +684,8 @@ def do_export(parser):
                 peer = bzrlib.branch.Branch.open(peers[name],
                                                  possible_transports=transports)
                 try:
-                    peer.bzrdir.push_branch(branch, revision_id=revid)
+                    peer.bzrdir.push_branch(branch, revision_id=revid,
+                                            overwrite=force)
                 except bzrlib.errors.DivergedBranches:
                     print "error %s non-fast forward" % ref
                     continue
@@ -718,8 +719,32 @@ def do_capabilities(parser):
         print "*import-marks %s" % path
     print "*export-marks %s" % path
 
+    print "option"
     print
 
+class InvalidOptionValue(Exception):
+    pass
+
+def get_bool_option(val):
+    if val == 'true':
+        return True
+    elif val == 'false':
+        return False
+    else:
+        raise InvalidOptionValue()
+
+def do_option(parser):
+    global force
+    opt, val = parser[1:3]
+    try:
+        if opt == 'force':
+            force = get_bool_option(val)
+            print 'ok'
+        else:
+            print 'unsupported'
+    except InvalidOptionValue:
+        print "error '%s' is not a valid value for option '%s'" % (val, opt)
+
 def ref_is_valid(name):
     return not True in [c in name for c in '~^: \\']
 
@@ -882,6 +907,7 @@ def main(args):
     global is_tmp
     global branches, peers
     global transports
+    global force
 
     marks = None
     is_tmp = False
@@ -904,6 +930,7 @@ def main(args):
     branches = {}
     peers = {}
     transports = []
+    force = False
 
     if alias[5:] == url:
         is_tmp = True
@@ -936,6 +963,8 @@ def main(args):
             do_import(parser)
         elif parser.check('export'):
             do_export(parser)
+        elif parser.check('option'):
+            do_option(parser)
         else:
             die('unhandled command: %s' % line)
         sys.stdout.flush()
diff --git a/contrib/remote-helpers/test-bzr.sh b/contrib/remote-helpers/test-bzr.sh
index 1e53ff9a58..4f379c2ab4 100755
--- a/contrib/remote-helpers/test-bzr.sh
+++ b/contrib/remote-helpers/test-bzr.sh
@@ -66,13 +66,33 @@ test_expect_success 'pushing' '
 	test_cmp expected actual
 '
 
+test_expect_success 'forced pushing' '
+	(
+	cd gitrepo &&
+	echo three-new >content &&
+	git commit -a --amend -m three-new &&
+	git push -f
+	) &&
+
+	(
+	cd bzrrepo &&
+	# the forced update overwrites the bzr branch but not the bzr
+	# working directory (it tries to merge instead)
+	bzr revert
+	) &&
+
+	echo three-new >expected &&
+	cat bzrrepo/content >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'roundtrip' '
 	(
 	cd gitrepo &&
 	git pull &&
 	git log --format="%s" -1 origin/master >actual
 	) &&
-	echo three >expected &&
+	echo three-new >expected &&
 	test_cmp expected actual &&
 
 	(cd gitrepo && git push && git pull) &&
diff --git a/contrib/remote-helpers/test-hg.sh b/contrib/remote-helpers/test-hg.sh
index 5d128a5da9..a933b1e30c 100755
--- a/contrib/remote-helpers/test-hg.sh
+++ b/contrib/remote-helpers/test-hg.sh
@@ -680,7 +680,7 @@ test_expect_success 'remote big push fetch first' '
 	)
 '
 
-test_expect_failure 'remote big push force' '
+test_expect_success 'remote big push force' '
 	test_when_finished "rm -rf hgrepo gitrepo*" &&
 
 	setup_big_push
@@ -710,7 +710,7 @@ test_expect_failure 'remote big push force' '
 	check_bookmark hgrepo new_bmark six
 '
 
-test_expect_failure 'remote big push dry-run' '
+test_expect_success 'remote big push dry-run' '
 	test_when_finished "rm -rf hgrepo gitrepo*" &&
 
 	setup_big_push
diff --git a/git-remote-testgit.sh b/git-remote-testgit.sh
index 6d2f282d32..1c006a0518 100755
--- a/git-remote-testgit.sh
+++ b/git-remote-testgit.sh
@@ -15,6 +15,8 @@ test -z "$refspec" && prefix="refs"
 
 export GIT_DIR="$url/.git"
 
+force=
+
 mkdir -p "$dir"
 
 if test -z "$GIT_REMOTE_TESTGIT_NO_MARKS"
@@ -39,6 +41,7 @@ do
 		fi
 		test -n "$GIT_REMOTE_TESTGIT_SIGNED_TAGS" && echo "signed-tags"
 		test -n "$GIT_REMOTE_TESTGIT_NO_PRIVATE_UPDATE" && echo "no-private-update"
+		echo 'option'
 		echo
 		;;
 	list)
@@ -93,6 +96,7 @@ do
 		before=$(git for-each-ref --format=' %(refname) %(objectname) ')
 
 		git fast-import \
+			${force:+--force} \
 			${testgitmarks:+"--import-marks=$testgitmarks"} \
 			${testgitmarks:+"--export-marks=$testgitmarks"} \
 			--quiet
@@ -115,6 +119,20 @@ do
 
 		echo
 		;;
+	option\ *)
+		read cmd opt val <<-EOF
+		$line
+		EOF
+		case $opt in
+		force)
+			test $val = "true" && force="true" || force=
+			echo "ok"
+			;;
+		*)
+			echo "unsupported"
+			;;
+		esac
+		;;
 	'')
 		exit
 		;;
diff --git a/t/t5801-remote-helpers.sh b/t/t5801-remote-helpers.sh
index 613f69a254..c33cc25805 100755
--- a/t/t5801-remote-helpers.sh
+++ b/t/t5801-remote-helpers.sh
@@ -94,6 +94,19 @@ test_expect_failure 'push new branch with old:new refspec' '
 	compare_refs local HEAD server refs/heads/new-refspec
 '
 
+test_expect_success 'forced push' '
+	(cd local &&
+	git checkout -b force-test &&
+	echo content >> file &&
+	git commit -a -m eight &&
+	git push origin force-test &&
+	echo content >> file &&
+	git commit -a --amend -m eight-modified &&
+	git push --force origin force-test
+	) &&
+	compare_refs local refs/heads/force-test server refs/heads/force-test
+'
+
 test_expect_success 'cloning without refspec' '
 	GIT_REMOTE_TESTGIT_REFSPEC="" \
 	git clone "testgit::${PWD}/server" local2 2>error &&
diff --git a/transport-helper.c b/transport-helper.c
index ad72fbd53c..86e1679c1e 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -650,7 +650,7 @@ static int push_update_ref_status(struct strbuf *buf,
 				   struct ref *remote_refs)
 {
 	char *refname, *msg;
-	int status;
+	int status, forced = 0;
 
 	if (starts_with(buf->buf, "ok ")) {
 		status = REF_STATUS_OK;
@@ -708,6 +708,11 @@ static int push_update_ref_status(struct strbuf *buf,
 			free(msg);
 			msg = NULL;
 		}
+		else if (!strcmp(msg, "forced update")) {
+			forced = 1;
+			free(msg);
+			msg = NULL;
+		}
 	}
 
 	if (*ref)
@@ -729,12 +734,14 @@ static int push_update_ref_status(struct strbuf *buf,
 	}
 
 	(*ref)->status = status;
+	(*ref)->forced_update |= forced;
 	(*ref)->remote_status = msg;
 	return !(status == REF_STATUS_OK);
 }
 
 static void push_update_refs_status(struct helper_data *data,
-				    struct ref *remote_refs)
+				    struct ref *remote_refs,
+				    int flags)
 {
 	struct strbuf buf = STRBUF_INIT;
 	struct ref *ref = remote_refs;
@@ -748,7 +755,7 @@ static void push_update_refs_status(struct helper_data *data,
 		if (push_update_ref_status(&buf, &ref, remote_refs))
 			continue;
 
-		if (!data->refspecs || data->no_private_update)
+		if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 			continue;
 
 		/* propagate back the update to the remote namespace */
@@ -839,7 +846,7 @@ static int push_refs_with_push(struct transport *transport,
 	sendline(data, &buf);
 	strbuf_release(&buf);
 
-	push_update_refs_status(data, remote_refs);
+	push_update_refs_status(data, remote_refs, flags);
 	return 0;
 }
 
@@ -860,6 +867,11 @@ static int push_refs_with_export(struct transport *transport,
 			die("helper %s does not support dry-run", data->name);
 	}
 
+	if (flags & TRANSPORT_PUSH_FORCE) {
+		if (set_helper_option(transport, "force", "true") != 0)
+			warning("helper %s does not support 'force'", data->name);
+	}
+
 	helper = get_helper(transport);
 
 	write_constant(helper->in, "export\n");
@@ -881,9 +893,6 @@ static int push_refs_with_export(struct transport *transport,
 		}
 		free(private);
 
-		if (ref->deletion)
-			die("remote-helpers do not support ref deletion");
-
 		if (ref->peer_ref) {
 			if (strcmp(ref->peer_ref->name, ref->name))
 				die("remote-helpers do not support old:new syntax");
@@ -896,7 +905,7 @@ static int push_refs_with_export(struct transport *transport,
 
 	if (finish_command(&exporter))
 		die("Error while running fast-export");
-	push_update_refs_status(data, remote_refs);
+	push_update_refs_status(data, remote_refs, flags);
 	return 0;
 }