From: Junio C Hamano <gitster@pobox.com>
Date: Thu, 18 Aug 2011 00:35:58 +0000 (-0700)
Subject: Merge branch 'jc/maint-smart-http-race-upload-pack'
X-Git-Tag: v1.7.7-rc0~26
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/2f5cb6aa1e2eb7b12df85d5ddc4d8bc79be47b3d?ds=inline;hp=-c

Merge branch 'jc/maint-smart-http-race-upload-pack'

* jc/maint-smart-http-race-upload-pack:
helping smart-http/stateless-rpc fetch race
---

2f5cb6aa1e2eb7b12df85d5ddc4d8bc79be47b3d
diff --combined upload-pack.c
index 267e5b1d82,a9a6c0cb24..6420918abe
--- a/upload-pack.c
+++ b/upload-pack.c
@@@ -10,6 -10,7 +10,7 @@@
  #include "revision.h"
  #include "list-objects.h"
  #include "run-command.h"
+ #include "sigchain.h"
  
  static const char upload_pack_usage[] = "git upload-pack [--strict] [--timeout=<n>] <dir>";
  
@@@ -498,11 -499,95 +499,95 @@@ static int get_common_commits(void
  	}
  }
  
+ static void check_non_tip(void)
+ {
+ 	static const char *argv[] = {
+ 		"rev-list", "--stdin", NULL,
+ 	};
+ 	static struct child_process cmd;
+ 	struct object *o;
+ 	char namebuf[42]; /* ^ + SHA-1 + LF */
+ 	int i;
+ 
+ 	/* In the normal in-process case non-tip request can never happen */
+ 	if (!stateless_rpc)
+ 		goto error;
+ 
+ 	cmd.argv = argv;
+ 	cmd.git_cmd = 1;
+ 	cmd.no_stderr = 1;
+ 	cmd.in = -1;
+ 	cmd.out = -1;
+ 
+ 	if (start_command(&cmd))
+ 		goto error;
+ 
+ 	/*
+ 	 * If rev-list --stdin encounters an unknown commit, it
+ 	 * terminates, which will cause SIGPIPE in the write loop
+ 	 * below.
+ 	 */
+ 	sigchain_push(SIGPIPE, SIG_IGN);
+ 
+ 	namebuf[0] = '^';
+ 	namebuf[41] = '\n';
+ 	for (i = get_max_object_index(); 0 < i; ) {
+ 		o = get_indexed_object(--i);
+ 		if (!(o->flags & OUR_REF))
+ 			continue;
+ 		memcpy(namebuf + 1, sha1_to_hex(o->sha1), 40);
+ 		if (write_in_full(cmd.in, namebuf, 42) < 0)
+ 			goto error;
+ 	}
+ 	namebuf[40] = '\n';
+ 	for (i = 0; i < want_obj.nr; i++) {
+ 		o = want_obj.objects[i].item;
+ 		if (o->flags & OUR_REF)
+ 			continue;
+ 		memcpy(namebuf, sha1_to_hex(o->sha1), 40);
+ 		if (write_in_full(cmd.in, namebuf, 41) < 0)
+ 			goto error;
+ 	}
+ 	close(cmd.in);
+ 
+ 	sigchain_pop(SIGPIPE);
+ 
+ 	/*
+ 	 * The commits out of the rev-list are not ancestors of
+ 	 * our ref.
+ 	 */
+ 	i = read_in_full(cmd.out, namebuf, 1);
+ 	if (i)
+ 		goto error;
+ 	close(cmd.out);
+ 
+ 	/*
+ 	 * rev-list may have died by encountering a bad commit
+ 	 * in the history, in which case we do want to bail out
+ 	 * even when it showed no commit.
+ 	 */
+ 	if (finish_command(&cmd))
+ 		goto error;
+ 
+ 	/* All the non-tip ones are ancestors of what we advertised */
+ 	return;
+ 
+ error:
+ 	/* Pick one of them (we know there at least is one) */
+ 	for (i = 0; i < want_obj.nr; i++) {
+ 		o = want_obj.objects[i].item;
+ 		if (!(o->flags & OUR_REF))
+ 			die("git upload-pack: not our ref %s",
+ 			    sha1_to_hex(o->sha1));
+ 	}
+ }
+ 
  static void receive_needs(void)
  {
  	struct object_array shallows = OBJECT_ARRAY_INIT;
  	static char line[1000];
  	int len, depth = 0;
+ 	int has_non_tip = 0;
  
  	shallow_nr = 0;
  	if (debug_fd)
@@@ -559,26 -644,30 +644,30 @@@
  		if (strstr(line+45, "include-tag"))
  			use_include_tag = 1;
  
- 		/* We have sent all our refs already, and the other end
- 		 * should have chosen out of them; otherwise they are
- 		 * asking for nonsense.
- 		 *
- 		 * Hmph.  We may later want to allow "want" line that
- 		 * asks for something like "master~10" (symbolic)...
- 		 * would it make sense?  I don't know.
- 		 */
  		o = lookup_object(sha1_buf);
- 		if (!o || !(o->flags & OUR_REF))
+ 		if (!o)
  			die("git upload-pack: not our ref %s",
  			    sha1_to_hex(sha1_buf));
  		if (!(o->flags & WANTED)) {
  			o->flags |= WANTED;
+ 			if (!(o->flags & OUR_REF))
+ 				has_non_tip = 1;
  			add_object_array(o, NULL, &want_obj);
  		}
  	}
  	if (debug_fd)
  		write_str_in_full(debug_fd, "#E\n");
  
+ 	/*
+ 	 * We have sent all our refs already, and the other end
+ 	 * should have chosen out of them. When we are operating
+ 	 * in the stateless RPC mode, however, their choice may
+ 	 * have been based on the set of older refs advertised
+ 	 * by another process that handled the initial request.
+ 	 */
+ 	if (has_non_tip)
+ 		check_non_tip();
+ 
  	if (!use_sideband && daemon_mode)
  		no_progress = 1;
  
@@@ -641,17 -730,16 +730,17 @@@ static int send_ref(const char *refname
  		" side-band-64k ofs-delta shallow no-progress"
  		" include-tag multi_ack_detailed";
  	struct object *o = parse_object(sha1);
 +	const char *refname_nons = strip_namespace(refname);
  
  	if (!o)
  		die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
  
  	if (capabilities)
 -		packet_write(1, "%s %s%c%s%s\n", sha1_to_hex(sha1), refname,
 +		packet_write(1, "%s %s%c%s%s\n", sha1_to_hex(sha1), refname_nons,
  			     0, capabilities,
  			     stateless_rpc ? " no-done" : "");
  	else
 -		packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 +		packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname_nons);
  	capabilities = NULL;
  	if (!(o->flags & OUR_REF)) {
  		o->flags |= OUR_REF;
@@@ -660,7 -748,7 +749,7 @@@
  	if (o->type == OBJ_TAG) {
  		o = deref_tag(o, refname, 0);
  		if (o)
 -			packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 +			packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname_nons);
  	}
  	return 0;
  }
@@@ -681,12 -769,12 +770,12 @@@ static void upload_pack(void
  {
  	if (advertise_refs || !stateless_rpc) {
  		reset_timeout();
 -		head_ref(send_ref, NULL);
 -		for_each_ref(send_ref, NULL);
 +		head_ref_namespaced(send_ref, NULL);
 +		for_each_namespaced_ref(send_ref, NULL);
  		packet_flush(1);
  	} else {
 -		head_ref(mark_our_ref, NULL);
 -		for_each_ref(mark_our_ref, NULL);
 +		head_ref_namespaced(mark_our_ref, NULL);
 +		for_each_namespaced_ref(mark_our_ref, NULL);
  	}
  	if (advertise_refs)
  		return;