[PATCH] http-backend: Treat empty CONTENT_LENGTH as zero

[Max Kirillov <max@max630.net>]

From: Jeff King <peff@peff.net>
Subject: [PATCH] http-backend: Treat empty CONTENT_LENGTH as zero

There is no known case where empty body it used by a server as
instruction to read until EOF, so there is no need to violate the RFC.
Make get_content_length() return 0 in this case.

Currently there is no practical difference, as the GET request
where it can be empty is handled without actual reading the body
(in get_info_refs() function), but it is better to stick to the correct
behavior.

Signed-off-by: Max Kirillov <max@max630.net>
---
The incremental. Hopefully I described the reason right. Needs "signed-off-by"
 http-backend.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/http-backend.c b/http-backend.c
index 458642ef72..ea36a52118 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -353,8 +353,28 @@ static ssize_t get_content_length(void)
 	ssize_t val = -1;
 	const char *str = getenv("CONTENT_LENGTH");
 
-	if (str && *str && !git_parse_ssize_t(str, &val))
-		die("failed to parse CONTENT_LENGTH: %s", str);
+	if (!str) {
+		/*
+		 * RFC3875 says this must mean "no body", but in practice we
+		 * receive chunked encodings with no CONTENT_LENGTH. Tell the
+		 * caller to read until EOF.
+		 */
+		val = -1;
+	} else if (!*str) {
+		/*
+		 * An empty length should be treated as "no body" according to
+		 * RFC3875, and this seems to hold in practice.
+		 */
+		val = 0;
+	} else {
+		/*
+		 * We have a non-empty CONTENT_LENGTH; trust what's in it as long
+		 * as it can be parsed.
+		 */
+		if (!git_parse_ssize_t(str, &val))
+			die("failed to parse CONTENT_LENGTH: '%s'", str);
+	}
+
 	return val;
 }
 
-- 
2.17.0.1185.g782057d875