push: parse and set flag for "--force-if-includes"

The previous commit added the necessary machinery to implement the
"--force-if-includes" protection, when "--force-with-lease" is used
without giving exact object the remote still ought to have. Surface
the feature by adding a command line option and a configuration
variable to enable it.

 - Add a flag: "TRANSPORT_PUSH_FORCE_IF_INCLUDES" to indicate that the
   new option was passed from the command line of via configuration
   settings; update command line and configuration parsers to set the
   new flag accordingly.

 - Introduce a new configuration option "push.useForceIfIncludes", which
   is equivalent to setting "--force-if-includes" in the command line.

 - Update "remote-curl" to recognize and pass this option to "send-pack"
   when enabled.

 - Update "advise" to catch the reject reason "REJECT_REF_NEEDS_UPDATE",
   set when the ref status is "REF_STATUS_REJECT_REMOTE_UPDATED" and
   (optionally) print a help message when the push fails.

 - The new option is a "no-op" in the following scenarios:
    * When used without "--force-with-lease".
    * When used with "--force-with-lease", and if the expected commit
      on the remote side is specified as an argument.

Signed-off-by: Srinidhi Kaushik <shrinidhi.kaushik@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

8 files changed, 68 insertions, 6 deletions

diff --git a/advice.c b/advice.c
index f0a3d32d20..164742305f 100644
--- a/advice.c
+++ b/advice.c
@@ -11,6 +11,7 @@ int advice_push_already_exists = 1;
 int advice_push_fetch_first = 1;
 int advice_push_needs_force = 1;
 int advice_push_unqualified_ref_name = 1;
+int advice_push_ref_needs_update = 1;
 int advice_status_hints = 1;
 int advice_status_u_option = 1;
 int advice_status_ahead_behind_warning = 1;
@@ -72,6 +73,7 @@ static struct {
 	{ "pushFetchFirst", &advice_push_fetch_first },
 	{ "pushNeedsForce", &advice_push_needs_force },
 	{ "pushUnqualifiedRefName", &advice_push_unqualified_ref_name },
+	{ "pushRefNeedsUpdate", &advice_push_ref_needs_update },
 	{ "statusHints", &advice_status_hints },
 	{ "statusUoption", &advice_status_u_option },
 	{ "statusAheadBehindWarning", &advice_status_ahead_behind_warning },
@@ -116,6 +118,7 @@ static struct {
 	[ADVICE_PUSH_ALREADY_EXISTS]			= { "pushAlreadyExists", 1 },
 	[ADVICE_PUSH_FETCH_FIRST]			= { "pushFetchFirst", 1 },
 	[ADVICE_PUSH_NEEDS_FORCE]			= { "pushNeedsForce", 1 },
+	[ADVICE_PUSH_REF_NEEDS_UPDATE]			= { "pushRefNeedsUpdate", 1 },
 
 	/* make this an alias for backward compatibility */
 	[ADVICE_PUSH_UPDATE_REJECTED_ALIAS]		= { "pushNonFastForward", 1 },
diff --git a/advice.h b/advice.h
index 16f2c11642..bc2432980a 100644
--- a/advice.h
+++ b/advice.h
@@ -11,6 +11,7 @@ extern int advice_push_already_exists;
 extern int advice_push_fetch_first;
 extern int advice_push_needs_force;
 extern int advice_push_unqualified_ref_name;
+extern int advice_push_ref_needs_update;
 extern int advice_status_hints;
 extern int advice_status_u_option;
 extern int advice_status_ahead_behind_warning;
@@ -60,6 +61,7 @@ extern int advice_add_empty_pathspec;
 	ADVICE_PUSH_UNQUALIFIED_REF_NAME,
 	ADVICE_PUSH_UPDATE_REJECTED_ALIAS,
 	ADVICE_PUSH_UPDATE_REJECTED,
+	ADVICE_PUSH_REF_NEEDS_UPDATE,
 	ADVICE_RESET_QUIET_WARNING,
 	ADVICE_RESOLVE_CONFLICT,
 	ADVICE_RM_HINTS,
diff --git a/builtin/push.c b/builtin/push.c
index 0eeb2c8dd5..908b557edb 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -290,6 +290,12 @@ static const char message_advice_ref_needs_force[] =
 	   "or update a remote ref to make it point at a non-commit object,\n"
 	   "without using the '--force' option.\n");
 
+static const char message_advice_ref_needs_update[] =
+	N_("Updates were rejected because the tip of the remote-tracking\n"
+	   "branch has been updated since the last checkout. You may want\n"
+	   "to integrate those changes locally (e.g., 'git pull ...')\n"
+	   "before forcing an update.\n");
+
 static void advise_pull_before_push(void)
 {
 	if (!advice_push_non_ff_current || !advice_push_update_rejected)
@@ -325,6 +331,13 @@ static void advise_ref_needs_force(void)
 	advise(_(message_advice_ref_needs_force));
 }
 
+static void advise_ref_needs_update(void)
+{
+	if (!advice_push_ref_needs_update || !advice_push_update_rejected)
+		return;
+	advise(_(message_advice_ref_needs_update));
+}
+
 static int push_with_options(struct transport *transport, struct refspec *rs,
 			     int flags)
 {
@@ -374,6 +387,8 @@ static int push_with_options(struct transport *transport, struct refspec *rs,
 		advise_ref_fetch_first();
 	} else if (reject_reasons & REJECT_NEEDS_FORCE) {
 		advise_ref_needs_force();
+	} else if (reject_reasons & REJECT_REF_NEEDS_UPDATE) {
+		advise_ref_needs_update();
 	}
 
 	return 1;
@@ -510,6 +525,12 @@ static int git_push_config(const char *k, const char *v, void *cb)
 		if (!v)
 			return config_error_nonbool(k);
 		return color_parse(v, push_colors[slot]);
+	} else if (!strcmp(k, "push.useforceifincludes")) {
+		if (git_config_bool(k, v))
+			*flags |= TRANSPORT_PUSH_FORCE_IF_INCLUDES;
+		else
+			*flags &= ~TRANSPORT_PUSH_FORCE_IF_INCLUDES;
+		return 0;
 	}
 
 	return git_default_config(k, v, NULL);
@@ -541,6 +562,9 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 		OPT_CALLBACK_F(0, CAS_OPT_NAME, &cas, N_("<refname>:<expect>"),
 			       N_("require old value of ref to be at this value"),
 			       PARSE_OPT_OPTARG | PARSE_OPT_LITERAL_ARGHELP, parseopt_push_cas_option),
+		OPT_BIT(0, TRANS_OPT_FORCE_IF_INCLUDES, &flags,
+			N_("require remote updates to be integrated locally"),
+			TRANSPORT_PUSH_FORCE_IF_INCLUDES),
 		OPT_CALLBACK(0, "recurse-submodules", &recurse_submodules, "(check|on-demand|no)",
 			     N_("control recursive pushing of submodules"), option_parse_recurse_submodules),
 		OPT_BOOL_F( 0 , "thin", &thin, N_("use thin pack"), PARSE_OPT_NOCOMPLETE),
@@ -625,6 +649,9 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 	if ((flags & TRANSPORT_PUSH_ALL) && (flags & TRANSPORT_PUSH_MIRROR))
 		die(_("--all and --mirror are incompatible"));
 
+	if (!is_empty_cas(&cas) && (flags & TRANSPORT_PUSH_FORCE_IF_INCLUDES))
+		cas.use_force_if_includes = 1;
+
 	for_each_string_list_item(item, push_options)
 		if (strchr(item->string, '\n'))
 			die(_("push options must not have new line characters"));
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index 516cba7336..a7e01667b0 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -178,6 +178,7 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
 	int progress = -1;
 	int from_stdin = 0;
 	struct push_cas_option cas = {0};
+	int force_if_includes = 0;
 	struct packet_reader reader;
 
 	struct option options[] = {
@@ -203,6 +204,8 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
 		OPT_CALLBACK_F(0, CAS_OPT_NAME, &cas, N_("<refname>:<expect>"),
 		  N_("require old value of ref to be at this value"),
 		  PARSE_OPT_OPTARG, parseopt_push_cas_option),
+		OPT_BOOL(0, TRANS_OPT_FORCE_IF_INCLUDES, &force_if_includes,
+			 N_("require remote updates to be integrated locally")),
 		OPT_END()
 	};
 
@@ -304,6 +307,9 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
 	if (!is_empty_cas(&cas))
 		apply_push_cas(&cas, remote, remote_refs);
 
+	if (!is_empty_cas(&cas) && force_if_includes)
+		cas.use_force_if_includes = 1;
+
 	set_ref_status_for_push(remote_refs, args.send_mirror,
 		args.force_update);
 
diff --git a/remote-curl.c b/remote-curl.c
index 32cc4a0c55..0290b04891 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -44,7 +44,8 @@ struct options {
 		from_promisor : 1,
 
 		atomic : 1,
-		object_format : 1;
+		object_format : 1,
+		force_if_includes : 1;
 	const struct git_hash_algo *hash_algo;
 };
 static struct options options;
@@ -131,6 +132,14 @@ static int set_option(const char *name, const char *value)
 		string_list_append(&cas_options, val.buf);
 		strbuf_release(&val);
 		return 0;
+	} else if (!strcmp(name, TRANS_OPT_FORCE_IF_INCLUDES)) {
+		if (!strcmp(value, "true"))
+			options.force_if_includes = 1;
+		else if (!strcmp(value, "false"))
+			options.force_if_includes = 0;
+		else
+			return -1;
+		return 0;
 	} else if (!strcmp(name, "cloning")) {
 		if (!strcmp(value, "true"))
 			options.cloning = 1;
@@ -1318,6 +1327,9 @@ static int push_git(struct discovery *heads, int nr_spec, const char **specs)
 		strvec_push(&args, cas_option->string);
 	strvec_push(&args, url.buf);
 
+	if (options.force_if_includes)
+		strvec_push(&args, "--force-if-includes");
+
 	strvec_push(&args, "--stdin");
 	for (i = 0; i < nr_spec; i++)
 		packet_buf_write(&preamble, "%s\n", specs[i]);
diff --git a/transport-helper.c b/transport-helper.c
index 6157de30c7..5f6e0b3bd8 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -938,6 +938,11 @@ static void set_common_push_options(struct transport *transport,
 		if (set_helper_option(transport, TRANS_OPT_ATOMIC, "true") != 0)
 			die(_("helper %s does not support --atomic"), name);
 
+	if (flags & TRANSPORT_PUSH_FORCE_IF_INCLUDES)
+		if (set_helper_option(transport, TRANS_OPT_FORCE_IF_INCLUDES, "true") != 0)
+			die(_("helper %s does not support --%s"),
+			    name, TRANS_OPT_FORCE_IF_INCLUDES);
+
 	if (flags & TRANSPORT_PUSH_OPTIONS) {
 		struct string_list_item *item;
 		for_each_string_list_item(item, transport->push_options)
diff --git a/transport.c b/transport.c
index 65fcd22b20..47da955e4f 100644
--- a/transport.c
+++ b/transport.c
@@ -748,6 +748,8 @@ void transport_print_push_status(const char *dest, struct ref *refs,
 			*reject_reasons |= REJECT_FETCH_FIRST;
 		} else if (ref->status == REF_STATUS_REJECT_NEEDS_FORCE) {
 			*reject_reasons |= REJECT_NEEDS_FORCE;
+		} else if (ref->status == REF_STATUS_REJECT_REMOTE_UPDATED) {
+			*reject_reasons |= REJECT_REF_NEEDS_UPDATE;
 		}
 	}
 	free(head);
diff --git a/transport.h b/transport.h
index ca409ea1e4..24558c027d 100644
--- a/transport.h
+++ b/transport.h
@@ -136,6 +136,7 @@ struct transport {
 #define TRANSPORT_PUSH_ATOMIC			(1<<13)
 #define TRANSPORT_PUSH_OPTIONS			(1<<14)
 #define TRANSPORT_RECURSE_SUBMODULES_ONLY	(1<<15)
+#define TRANSPORT_PUSH_FORCE_IF_INCLUDES	(1<<16)
 
 int transport_summary_width(const struct ref *refs);
 
@@ -208,6 +209,9 @@ void transport_check_allowed(const char *type);
 /* Request atomic (all-or-nothing) updates when pushing */
 #define TRANS_OPT_ATOMIC "atomic"
 
+/* Require remote changes to be integrated locally. */
+#define TRANS_OPT_FORCE_IF_INCLUDES "force-if-includes"
+
 /**
  * Returns 0 if the option was used, non-zero otherwise. Prints a
  * message to stderr if the option is not used.
@@ -217,11 +221,12 @@ int transport_set_option(struct transport *transport, const char *name,
 void transport_set_verbosity(struct transport *transport, int verbosity,
 	int force_progress);
 
-#define REJECT_NON_FF_HEAD     0x01
-#define REJECT_NON_FF_OTHER    0x02
-#define REJECT_ALREADY_EXISTS  0x04
-#define REJECT_FETCH_FIRST     0x08
-#define REJECT_NEEDS_FORCE     0x10
+#define REJECT_NON_FF_HEAD      0x01
+#define REJECT_NON_FF_OTHER     0x02
+#define REJECT_ALREADY_EXISTS   0x04
+#define REJECT_FETCH_FIRST      0x08
+#define REJECT_NEEDS_FORCE      0x10
+#define REJECT_REF_NEEDS_UPDATE 0x20
 
 int transport_push(struct repository *repo,
 		   struct transport *connection,