Merge branch 'jc/push-cas'

Allow a safer "rewind of the remote tip" push than blind "--force",
by requiring that the overwritten remote ref to be unchanged since
the new history to replace it was prepared.

The machinery is more or less ready.  The "--force" option is again
the big red button to override any safety, thanks to J6t's sanity
(the original round allowed --lockref to defeat --force).

The logic to choose the default implemented here is fragile
(e.g. "git fetch" after seeing a failure will update the
remote-tracking branch and will make the next "push" pass,
defeating the safety pretty easily).  It is suitable only for the
simplest workflows, and it may hurt users more than it helps them.

* jc/push-cas:
  push: teach --force-with-lease to smart-http transport
  send-pack: fix parsing of --force-with-lease option
  t5540/5541: smart-http does not support "--force-with-lease"
  t5533: test "push --force-with-lease"
  push --force-with-lease: tie it all together
  push --force-with-lease: implement logic to populate old_sha1_expect[]
  remote.c: add command line option parser for "--force-with-lease"
  builtin/push.c: use OPT_BOOL, not OPT_BOOLEAN
  cache.h: move remote/connect API out of it

1 files changed, 28 insertions, 2 deletions

diff --git a/transport-helper.c b/transport-helper.c
index bec3b721fa..4c2a39e8ff 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -693,6 +693,11 @@ static int push_update_ref_status(struct strbuf *buf,
 			free(msg);
 			msg = NULL;
 		}
+		else if (!strcmp(msg, "stale info")) {
+			status = REF_STATUS_REJECT_STALE;
+			free(msg);
+			msg = NULL;
+		}
 	}
 
 	if (*ref)
@@ -747,13 +752,15 @@ static void push_update_refs_status(struct helper_data *data,
 }
 
 static int push_refs_with_push(struct transport *transport,
-		struct ref *remote_refs, int flags)
+			       struct ref *remote_refs, int flags)
 {
 	int force_all = flags & TRANSPORT_PUSH_FORCE;
 	int mirror = flags & TRANSPORT_PUSH_MIRROR;
 	struct helper_data *data = transport->data;
 	struct strbuf buf = STRBUF_INIT;
 	struct ref *ref;
+	struct string_list cas_options = STRING_LIST_INIT_DUP;
+	struct string_list_item *cas_option;
 
 	get_helper(transport);
 	if (!data->push)
@@ -766,6 +773,7 @@ static int push_refs_with_push(struct transport *transport,
 		/* Check for statuses set by set_ref_status_for_push() */
 		switch (ref->status) {
 		case REF_STATUS_REJECT_NONFASTFORWARD:
+		case REF_STATUS_REJECT_STALE:
 		case REF_STATUS_REJECT_ALREADY_EXISTS:
 		case REF_STATUS_UPTODATE:
 			continue;
@@ -788,11 +796,29 @@ static int push_refs_with_push(struct transport *transport,
 		strbuf_addch(&buf, ':');
 		strbuf_addstr(&buf, ref->name);
 		strbuf_addch(&buf, '\n');
+
+		/*
+		 * The "--force-with-lease" options without explicit
+		 * values to expect have already been expanded into
+		 * the ref->old_sha1_expect[] field; we can ignore
+		 * transport->smart_options->cas altogether and instead
+		 * can enumerate them from the refs.
+		 */
+		if (ref->expect_old_sha1) {
+			struct strbuf cas = STRBUF_INIT;
+			strbuf_addf(&cas, "%s:%s",
+				    ref->name, sha1_to_hex(ref->old_sha1_expect));
+			string_list_append(&cas_options, strbuf_detach(&cas, NULL));
+		}
 	}
-	if (buf.len == 0)
+	if (buf.len == 0) {
+		string_list_clear(&cas_options, 0);
 		return 0;
+	}
 
 	standard_options(transport);
+	for_each_string_list_item(cas_option, &cas_options)
+		set_helper_option(transport, "cas", cas_option->string);
 
 	if (flags & TRANSPORT_PUSH_DRY_RUN) {
 		if (set_helper_option(transport, "dry-run", "true") != 0)