1 files changed, 270 insertions, 61 deletions

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index a01ac2096a..e0ce78e5a0 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1,4 +1,5 @@
 #include "builtin.h"
+#include "lockfile.h"
 #include "pack.h"
 #include "refs.h"
 #include "pkt-line.h"
@@ -25,7 +26,8 @@ enum deny_action {
 	DENY_UNCONFIGURED,
 	DENY_IGNORE,
 	DENY_WARN,
-	DENY_REFUSE
+	DENY_REFUSE,
+	DENY_UPDATE_INSTEAD
 };
 
 static int deny_deletes;
@@ -36,9 +38,11 @@ static int receive_fsck_objects = -1;
 static int transfer_fsck_objects = -1;
 static int receive_unpack_limit = -1;
 static int transfer_unpack_limit = -1;
+static int advertise_atomic_push = 1;
 static int unpack_limit = 100;
 static int report_status;
 static int use_sideband;
+static int use_atomic;
 static int quiet;
 static int prefer_ofs_delta = 1;
 static int auto_update_server_info;
@@ -65,6 +69,7 @@ static const char *NONCE_SLOP = "SLOP";
 static const char *nonce_status;
 static long nonce_stamp_slop;
 static unsigned long nonce_stamp_slop_limit;
+static struct ref_transaction *transaction;
 
 static enum deny_action parse_deny_action(const char *var, const char *value)
 {
@@ -75,6 +80,8 @@ static enum deny_action parse_deny_action(const char *var, const char *value)
 			return DENY_WARN;
 		if (!strcasecmp(value, "refuse"))
 			return DENY_REFUSE;
+		if (!strcasecmp(value, "updateinstead"))
+			return DENY_UPDATE_INSTEAD;
 	}
 	if (git_config_bool(var, value))
 		return DENY_REFUSE;
@@ -156,6 +163,11 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if (strcmp(var, "receive.advertiseatomic") == 0) {
+		advertise_atomic_push = git_config_bool(var, value);
+		return 0;
+	}
+
 	return git_default_config(var, value, cb);
 }
 
@@ -171,6 +183,8 @@ static void show_ref(const char *path, const unsigned char *sha1)
 
 		strbuf_addstr(&cap,
 			      "report-status delete-refs side-band-64k quiet");
+		if (advertise_atomic_push)
+			strbuf_addstr(&cap, " atomic");
 		if (prefer_ofs_delta)
 			strbuf_addstr(&cap, " ofs-delta");
 		if (push_cert_nonce)
@@ -430,7 +444,7 @@ static const char *check_nonce(const char *buf, size_t len)
 	nonce_stamp_slop = (long)ostamp - (long)stamp;
 
 	if (nonce_stamp_slop_limit &&
-	    abs(nonce_stamp_slop) <= nonce_stamp_slop_limit) {
+	    labs(nonce_stamp_slop) <= nonce_stamp_slop_limit) {
 		/*
 		 * Pretend as if the received nonce (which passes the
 		 * HMAC check, so it is not a forged by third-party)
@@ -452,7 +466,6 @@ leave:
 static void prepare_push_cert_sha1(struct child_process *proc)
 {
 	static int already_done;
-	struct argv_array env = ARGV_ARRAY_INIT;
 
 	if (!push_cert.len)
 		return;
@@ -486,20 +499,26 @@ static void prepare_push_cert_sha1(struct child_process *proc)
 		nonce_status = check_nonce(push_cert.buf, bogs);
 	}
 	if (!is_null_sha1(push_cert_sha1)) {
-		argv_array_pushf(&env, "GIT_PUSH_CERT=%s", sha1_to_hex(push_cert_sha1));
-		argv_array_pushf(&env, "GIT_PUSH_CERT_SIGNER=%s",
+		argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT=%s",
+				 sha1_to_hex(push_cert_sha1));
+		argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_SIGNER=%s",
 				 sigcheck.signer ? sigcheck.signer : "");
-		argv_array_pushf(&env, "GIT_PUSH_CERT_KEY=%s",
+		argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_KEY=%s",
 				 sigcheck.key ? sigcheck.key : "");
-		argv_array_pushf(&env, "GIT_PUSH_CERT_STATUS=%c", sigcheck.result);
+		argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_STATUS=%c",
+				 sigcheck.result);
 		if (push_cert_nonce) {
-			argv_array_pushf(&env, "GIT_PUSH_CERT_NONCE=%s", push_cert_nonce);
-			argv_array_pushf(&env, "GIT_PUSH_CERT_NONCE_STATUS=%s", nonce_status);
+			argv_array_pushf(&proc->env_array,
+					 "GIT_PUSH_CERT_NONCE=%s",
+					 push_cert_nonce);
+			argv_array_pushf(&proc->env_array,
+					 "GIT_PUSH_CERT_NONCE_STATUS=%s",
+					 nonce_status);
 			if (nonce_status == NONCE_SLOP)
-				argv_array_pushf(&env, "GIT_PUSH_CERT_NONCE_SLOP=%ld",
+				argv_array_pushf(&proc->env_array,
+						 "GIT_PUSH_CERT_NONCE_SLOP=%ld",
 						 nonce_stamp_slop);
 		}
-		proc->env = env.argv;
 	}
 }
 
@@ -521,8 +540,6 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
 	proc.in = -1;
 	proc.stdout_to_stderr = 1;
 
-	prepare_push_cert_sha1(&proc);
-
 	if (use_sideband) {
 		memset(&muxer, 0, sizeof(muxer));
 		muxer.proc = copy_to_sideband;
@@ -533,6 +550,8 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
 		proc.err = muxer.in;
 	}
 
+	prepare_push_cert_sha1(&proc);
+
 	code = start_command(&proc);
 	if (code) {
 		if (use_sideband)
@@ -724,11 +743,109 @@ static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 	return 0;
 }
 
+static const char *push_to_deploy(unsigned char *sha1,
+				  struct argv_array *env,
+				  const char *work_tree)
+{
+	const char *update_refresh[] = {
+		"update-index", "-q", "--ignore-submodules", "--refresh", NULL
+	};
+	const char *diff_files[] = {
+		"diff-files", "--quiet", "--ignore-submodules", "--", NULL
+	};
+	const char *diff_index[] = {
+		"diff-index", "--quiet", "--cached", "--ignore-submodules",
+		"HEAD", "--", NULL
+	};
+	const char *read_tree[] = {
+		"read-tree", "-u", "-m", NULL, NULL
+	};
+	struct child_process child = CHILD_PROCESS_INIT;
+
+	child.argv = update_refresh;
+	child.env = env->argv;
+	child.dir = work_tree;
+	child.no_stdin = 1;
+	child.stdout_to_stderr = 1;
+	child.git_cmd = 1;
+	if (run_command(&child))
+		return "Up-to-date check failed";
+
+	/* run_command() does not clean up completely; reinitialize */
+	child_process_init(&child);
+	child.argv = diff_files;
+	child.env = env->argv;
+	child.dir = work_tree;
+	child.no_stdin = 1;
+	child.stdout_to_stderr = 1;
+	child.git_cmd = 1;
+	if (run_command(&child))
+		return "Working directory has unstaged changes";
+
+	child_process_init(&child);
+	child.argv = diff_index;
+	child.env = env->argv;
+	child.no_stdin = 1;
+	child.no_stdout = 1;
+	child.stdout_to_stderr = 0;
+	child.git_cmd = 1;
+	if (run_command(&child))
+		return "Working directory has staged changes";
+
+	read_tree[3] = sha1_to_hex(sha1);
+	child_process_init(&child);
+	child.argv = read_tree;
+	child.env = env->argv;
+	child.dir = work_tree;
+	child.no_stdin = 1;
+	child.no_stdout = 1;
+	child.stdout_to_stderr = 0;
+	child.git_cmd = 1;
+	if (run_command(&child))
+		return "Could not update working tree to new HEAD";
+
+	return NULL;
+}
+
+static const char *push_to_checkout_hook = "push-to-checkout";
+
+static const char *push_to_checkout(unsigned char *sha1,
+				    struct argv_array *env,
+				    const char *work_tree)
+{
+	argv_array_pushf(env, "GIT_WORK_TREE=%s", absolute_path(work_tree));
+	if (run_hook_le(env->argv, push_to_checkout_hook,
+			sha1_to_hex(sha1), NULL))
+		return "push-to-checkout hook declined";
+	else
+		return NULL;
+}
+
+static const char *update_worktree(unsigned char *sha1)
+{
+	const char *retval;
+	const char *work_tree = git_work_tree_cfg ? git_work_tree_cfg : "..";
+	struct argv_array env = ARGV_ARRAY_INIT;
+
+	if (is_bare_repository())
+		return "denyCurrentBranch = updateInstead needs a worktree";
+
+	argv_array_pushf(&env, "GIT_DIR=%s", absolute_path(get_git_dir()));
+
+	if (!find_hook(push_to_checkout_hook))
+		retval = push_to_deploy(sha1, &env, work_tree);
+	else
+		retval = push_to_checkout(sha1, &env, work_tree);
+
+	argv_array_clear(&env);
+	return retval;
+}
+
 static const char *update(struct command *cmd, struct shallow_info *si)
 {
 	const char *name = cmd->ref_name;
 	struct strbuf namespaced_name_buf = STRBUF_INIT;
-	const char *namespaced_name;
+	const char *namespaced_name, *ret;
 	unsigned char *old_sha1 = cmd->old_sha1;
 	unsigned char *new_sha1 = cmd->new_sha1;
 
@@ -754,6 +871,11 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 			if (deny_current_branch == DENY_UNCONFIGURED)
 				refuse_unconfigured_deny();
 			return "branch is currently checked out";
+		case DENY_UPDATE_INSTEAD:
+			ret = update_worktree(new_sha1);
+			if (ret)
+				return ret;
+			break;
 		}
 	}
 
@@ -778,10 +900,13 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 				break;
 			case DENY_REFUSE:
 			case DENY_UNCONFIGURED:
+			case DENY_UPDATE_INSTEAD:
 				if (deny_delete_current == DENY_UNCONFIGURED)
 					refuse_unconfigured_deny_delete_current();
 				rp_error("refusing to delete the current branch: %s", name);
 				return "deletion of the current branch prohibited";
+			default:
+				return "Invalid denyDeleteCurrent setting";
 			}
 		}
 	}
@@ -815,6 +940,7 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 	}
 
 	if (is_null_sha1(new_sha1)) {
+		struct strbuf err = STRBUF_INIT;
 		if (!parse_object(old_sha1)) {
 			old_sha1 = NULL;
 			if (ref_exists(name)) {
@@ -824,34 +950,36 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 				cmd->did_not_exist = 1;
 			}
 		}
-		if (delete_ref(namespaced_name, old_sha1, 0)) {
-			rp_error("failed to delete %s", name);
+		if (ref_transaction_delete(transaction,
+					   namespaced_name,
+					   old_sha1,
+					   0, old_sha1 != NULL,
+					   "push", &err)) {
+			rp_error("%s", err.buf);
+			strbuf_release(&err);
 			return "failed to delete";
 		}
+		strbuf_release(&err);
 		return NULL; /* good */
 	}
 	else {
 		struct strbuf err = STRBUF_INIT;
-		struct ref_transaction *transaction;
-
 		if (shallow_update && si->shallow_ref[cmd->index] &&
 		    update_shallow_ref(cmd, si))
 			return "shallow error";
 
-		transaction = ref_transaction_begin(&err);
-		if (!transaction ||
-		    ref_transaction_update(transaction, namespaced_name,
-					   new_sha1, old_sha1, 0, 1, &err) ||
-		    ref_transaction_commit(transaction, "push", &err)) {
-			ref_transaction_free(transaction);
-
+		if (ref_transaction_update(transaction,
+					   namespaced_name,
+					   new_sha1, old_sha1,
+					   0, 1, "push",
+					   &err)) {
 			rp_error("%s", err.buf);
 			strbuf_release(&err);
+
 			return "failed to update ref";
 		}
-
-		ref_transaction_free(transaction);
 		strbuf_release(&err);
+
 		return NULL; /* good */
 	}
 }
@@ -907,7 +1035,7 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 	int flag;
 
 	strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
-	dst_name = resolve_ref_unsafe(buf.buf, sha1, 0, &flag);
+	dst_name = resolve_ref_unsafe(buf.buf, 0, sha1, &flag);
 	strbuf_release(&buf);
 
 	if (!(flag & REF_ISSYMREF))
@@ -957,7 +1085,7 @@ static void check_aliased_updates(struct command *commands)
 			string_list_append(&ref_list, cmd->ref_name);
 		item->util = (void *)cmd;
 	}
-	sort_string_list(&ref_list);
+	string_list_sort(&ref_list);
 
 	for (cmd = commands; cmd; cmd = cmd->next) {
 		if (!cmd->error_string)
@@ -1035,11 +1163,105 @@ static void reject_updates_to_hidden(struct command *commands)
 	}
 }
 
+static int should_process_cmd(struct command *cmd)
+{
+	return !cmd->error_string && !cmd->skip_update;
+}
+
+static void warn_if_skipped_connectivity_check(struct command *commands,
+					       struct shallow_info *si)
+{
+	struct command *cmd;
+	int checked_connectivity = 1;
+
+	for (cmd = commands; cmd; cmd = cmd->next) {
+		if (should_process_cmd(cmd) && si->shallow_ref[cmd->index]) {
+			error("BUG: connectivity check has not been run on ref %s",
+			      cmd->ref_name);
+			checked_connectivity = 0;
+		}
+	}
+	if (!checked_connectivity)
+		die("BUG: connectivity check skipped???");
+}
+
+static void execute_commands_non_atomic(struct command *commands,
+					struct shallow_info *si)
+{
+	struct command *cmd;
+	struct strbuf err = STRBUF_INIT;
+
+	for (cmd = commands; cmd; cmd = cmd->next) {
+		if (!should_process_cmd(cmd))
+			continue;
+
+		transaction = ref_transaction_begin(&err);
+		if (!transaction) {
+			rp_error("%s", err.buf);
+			strbuf_reset(&err);
+			cmd->error_string = "transaction failed to start";
+			continue;
+		}
+
+		cmd->error_string = update(cmd, si);
+
+		if (!cmd->error_string
+		    && ref_transaction_commit(transaction, &err)) {
+			rp_error("%s", err.buf);
+			strbuf_reset(&err);
+			cmd->error_string = "failed to update ref";
+		}
+		ref_transaction_free(transaction);
+	}
+	strbuf_release(&err);
+}
+
+static void execute_commands_atomic(struct command *commands,
+					struct shallow_info *si)
+{
+	struct command *cmd;
+	struct strbuf err = STRBUF_INIT;
+	const char *reported_error = "atomic push failure";
+
+	transaction = ref_transaction_begin(&err);
+	if (!transaction) {
+		rp_error("%s", err.buf);
+		strbuf_reset(&err);
+		reported_error = "transaction failed to start";
+		goto failure;
+	}
+
+	for (cmd = commands; cmd; cmd = cmd->next) {
+		if (!should_process_cmd(cmd))
+			continue;
+
+		cmd->error_string = update(cmd, si);
+
+		if (cmd->error_string)
+			goto failure;
+	}
+
+	if (ref_transaction_commit(transaction, &err)) {
+		rp_error("%s", err.buf);
+		reported_error = "atomic transaction failed";
+		goto failure;
+	}
+	goto cleanup;
+
+failure:
+	for (cmd = commands; cmd; cmd = cmd->next)
+		if (!cmd->error_string)
+			cmd->error_string = reported_error;
+
+cleanup:
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
+}
+
 static void execute_commands(struct command *commands,
 			     const char *unpacker_error,
 			     struct shallow_info *si)
 {
-	int checked_connectivity;
 	struct command *cmd;
 	unsigned char sha1[20];
 	struct iterate_data data;
@@ -1068,29 +1290,15 @@ static void execute_commands(struct command *commands,
 	check_aliased_updates(commands);
 
 	free(head_name_to_free);
-	head_name = head_name_to_free = resolve_refdup("HEAD", sha1, 0, NULL);
+	head_name = head_name_to_free = resolve_refdup("HEAD", 0, sha1, NULL);
 
-	checked_connectivity = 1;
-	for (cmd = commands; cmd; cmd = cmd->next) {
-		if (cmd->error_string)
-			continue;
-
-		if (cmd->skip_update)
-			continue;
-
-		cmd->error_string = update(cmd, si);
-		if (shallow_update && !cmd->error_string &&
-		    si->shallow_ref[cmd->index]) {
-			error("BUG: connectivity check has not been run on ref %s",
-			      cmd->ref_name);
-			checked_connectivity = 0;
-		}
-	}
+	if (use_atomic)
+		execute_commands_atomic(commands, si);
+	else
+		execute_commands_non_atomic(commands, si);
 
-	if (shallow_update && !checked_connectivity)
-		error("BUG: run 'git fsck' for safety.\n"
-		      "If there are errors, try to remove "
-		      "the reported refs above");
+	if (shallow_update)
+		warn_if_skipped_connectivity_check(commands, si);
 }
 
 static struct command **queue_command(struct command **tail,
@@ -1172,6 +1380,9 @@ static struct command *read_head_info(struct sha1_array *shallow)
 				use_sideband = LARGE_PACKET_MAX;
 			if (parse_feature_request(feature_list, "quiet"))
 				quiet = 1;
+			if (advertise_atomic_push
+			    && parse_feature_request(feature_list, "atomic"))
+				use_atomic = 1;
 		}
 
 		if (!strcmp(line, "push-cert")) {
@@ -1229,7 +1440,6 @@ static const char *pack_lockfile;
 static const char *unpack(int err_fd, struct shallow_info *si)
 {
 	struct pack_header hdr;
-	struct argv_array av = ARGV_ARRAY_INIT;
 	const char *hdr_err;
 	int status;
 	char hdr_arg[38];
@@ -1252,16 +1462,16 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 
 	if (si->nr_ours || si->nr_theirs) {
 		alt_shallow_file = setup_temporary_shallow(si->shallow);
-		argv_array_pushl(&av, "--shallow-file", alt_shallow_file, NULL);
+		argv_array_push(&child.args, "--shallow-file");
+		argv_array_push(&child.args, alt_shallow_file);
 	}
 
 	if (ntohl(hdr.hdr_entries) < unpack_limit) {
-		argv_array_pushl(&av, "unpack-objects", hdr_arg, NULL);
+		argv_array_pushl(&child.args, "unpack-objects", hdr_arg, NULL);
 		if (quiet)
-			argv_array_push(&av, "-q");
+			argv_array_push(&child.args, "-q");
 		if (fsck_objects)
-			argv_array_push(&av, "--strict");
-		child.argv = av.argv;
+			argv_array_push(&child.args, "--strict");
 		child.no_stdout = 1;
 		child.err = err_fd;
 		child.git_cmd = 1;
@@ -1276,13 +1486,12 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 		if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 			strcpy(keep_arg + s, "localhost");
 
-		argv_array_pushl(&av, "index-pack",
+		argv_array_pushl(&child.args, "index-pack",
 				 "--stdin", hdr_arg, keep_arg, NULL);
 		if (fsck_objects)
-			argv_array_push(&av, "--strict");
+			argv_array_push(&child.args, "--strict");
 		if (fix_thin)
-			argv_array_push(&av, "--fix-thin");
-		child.argv = av.argv;
+			argv_array_push(&child.args, "--fix-thin");
 		child.out = -1;
 		child.err = err_fd;
 		child.git_cmd = 1;