transport-helper: mention helper name when it dies

When we try to read from a remote-helper and get EOF or an
error, we print a message indicating that the helper died.
However, users may not know that a remote helper was in use
(e.g., when using git-over-http), or even what a remote
helper is.

Let's print the name of the helper (e.g., "git-remote-https");
this makes it more obvious what the program is for, and
provides a useful token for reporting bugs or searching for
more information (e.g., in manpages).

Signed-off-by: Jeff King <[email protected]>
Acked-by: Sverre Rabbelier <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

t/t5801-remote-helpers.sh

@@ -182,7 +182,7 @@ test_expect_success 'proper failure checks for pushing' '
 	cd local &&
 	test_must_fail git push --all 2> error &&
 	cat error &&
-	grep -q "Reading from remote helper failed" error
+	grep -q "Reading from helper .git-remote-testgit. failed" error
 	)
 '
 

transport-helper.c

@@ -46,15 +46,15 @@ static void sendline(struct helper_data *helper, struct strbuf *buffer)
 		die_errno("Full write to remote helper failed");
 }
 
-static int recvline_fh(FILE *helper, struct strbuf *buffer)
+static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
 {
 	strbuf_reset(buffer);
 	if (debug)
 		fprintf(stderr, "Debug: Remote helper: Waiting...\n");
 	if (strbuf_getline(buffer, helper, '\n') == EOF) {
 		if (debug)
 			fprintf(stderr, "Debug: Remote helper quit.\n");
-		die("Reading from remote helper failed");
+		die("Reading from helper 'git-remote-%s' failed", name);
 	}
 
 	if (debug)
@@ -64,7 +64,7 @@ static int recvline_fh(FILE *helper, struct strbuf *buffer)
 
 static int recvline(struct helper_data *helper, struct strbuf *buffer)
 {
-	return recvline_fh(helper->out, buffer);
+	return recvline_fh(helper->out, buffer, helper->name);
 }
 
 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
@@ -536,7 +536,7 @@ static int process_connect_service(struct transport *transport,
 		goto exit;
 
 	sendline(data, &cmdbuf);
-	recvline_fh(input, &cmdbuf);
+	recvline_fh(input, &cmdbuf, name);
 	if (!strcmp(cmdbuf.buf, "")) {
 		data->no_disconnect_req = 1;
 		if (debug)