From: Willy Tarreau <w@1wt.eu>
Date: Wed, 17 Apr 2024 07:36:33 +0000 (+0200)
Subject: BUILD: cache: fix a build warning with gcc < 7
X-Git-Tag: v3.0-dev8~37
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1c944eab08458b220861da4c17d32858534be6b2;p=thirdparty%2Fhaproxy.git

BUILD: cache: fix a build warning with gcc < 7

Gcc before 7 does really not like direct operations on cast pointers
such as "((struct a*)b)->c += d;". It turns our that we have exactly
that construct in 3.0 since commit 5baa9ea168 ("MEDIUM: cache: Save
body size of cached objects and track it on delivery").

It's generally sufficient to use an intermediary variable such as :
"({ (struct a*) _ = b; _; })->c +=d;" but that's ugly. Fortunately
DISGUISE() implicitly does something very similar and works fine, so
let's use that.

No backport is needed.
---

diff --git a/src/cache.c b/src/cache.c
index caa072ff22..4a9992a19c 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -820,7 +820,8 @@ cache_store_http_payload(struct stream *s, struct filter *filter, struct http_ms
 		goto no_cache;
 	}
 
-	((struct cache_entry *)st->first_block->data)->body_size += data_len;
+	/* disguise below to shut a warning on */
+	DISGUISE((struct cache_entry *)st->first_block->data)->body_size += data_len;
 	ret = shctx_row_data_append(shctx, st->first_block,
 				    (unsigned char *)b_head(&trash), b_data(&trash));
 	if (ret < 0)