Subject: [PATCH] connect: tighten check for unexpected early hang up (Re: [PATCH v3 2/2] connect: advertized capability is not a ref)

From: Jonathan Nieder <[email-masked]>
Date: Wed, 7 Sep 2016 18:45:55 -0700

(+cc: Heiko)
Jonathan Nieder wrote:

> 'die_initial_contact' uses got_at_least_one_head to determine whether
> it was on the first line but code paths added later that use
> 'continue' don't populate it properly (see b06dcd7d, 40c155ff, and
> 1a7141ff).  We could do
>
> 	int first_line = 1;
>
> 	for (;; first_line = 0) {
> 		...
> 	}
>
> and use !first_line instead of got_at_least_one_head (removing
> got_at_least_one_head in the process since it has no other purpose).

I got the history wrong.  It looks like this was always confused
by the 'continue' cases.  Unless I'm missing something subtle ---
thoughts?

Thanks,
Jonathan

-- >8 --
Subject: connect: tighten check for unexpected early hang up

A server hanging up immediately to mark access being denied does not
send any .have refs, shallow lines, or anything else before hanging
up.  If the server has sent anything, then the hangup is unexpected.

That is, if the server hangs up after a shallow line but before sending
any refs, then git should tell me so:

	fatal: The remote end hung up upon initial contact

instead of suggesting an access control problem:

	fatal: Could not read from remote repository.
	Please make sure you have the correct access rights
	and the repository exists.

Noticed while examining this code.  This case isn't likely to come up
in practice but tightening the check makes the code easier to read and
manipulate.

Change-Id: I3cec2c160eb6c6f3efdce7dab38a4c78592f6c7f
Signed-off-by: Jonathan Nieder <[email-masked]>
---
 connect.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/connect.c b/connect.c
index 722dc3f..2c2ebef 100644
--- a/connect.c
+++ b/connect.c
@@ -43,9 +43,9 @@ int check_ref_type(const struct ref *ref, int flags)
 	return check_ref(ref->name, flags);
 }
 
-static void die_initial_contact(int got_at_least_one_head)
+static void die_initial_contact(int unexpected)
 {
-	if (got_at_least_one_head)
+	if (unexpected)
 		die("The remote end hung up upon initial contact");
 	else
 		die("Could not read from remote repository.\n\n"
@@ -115,10 +115,10 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 			      struct sha1_array *shallow_points)
 {
 	struct ref **orig_list = list;
-	int got_at_least_one_head = 0;
+	int first_line = 1;
 
 	*list = NULL;
-	for (;;) {
+	for (;; first_line = 0) {
 		struct ref *ref;
 		struct object_id old_oid;
 		char *name;
@@ -131,7 +131,7 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 				  PACKET_READ_GENTLE_ON_EOF |
 				  PACKET_READ_CHOMP_NEWLINE);
 		if (len < 0)
-			die_initial_contact(got_at_least_one_head);
+			die_initial_contact(first_line);
 
 		if (!len)
 			break;
@@ -171,7 +171,6 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 		oidcpy(&ref->old_oid, &old_oid);
 		*list = ref;
 		list = &ref->next;
-		got_at_least_one_head = 1;
 	}
 
 	annotate_refs_with_symref_info(*orig_list);
--