From: Tiburce GIROUX <tgiroux@haproxy.com>
Date: Mon, 9 Nov 2026 18:13:37 +0000 (+0100)
Subject: BUG/MEDIUM: flt-decomp: preserve pending output before decoding again
X-Git-Url: https://git.kaiwu.me/$%7BGITURL%7D$%7Bcid%7D?a=commitdiff_plain;h=66e4be2fd0b47948b232f4a720fc8a9ac0ad8fb3;p=haproxy.git

BUG/MEDIUM: flt-decomp: preserve pending output before decoding again

The HTTP no-input path tries to drain the decompressor's pending output,
then may call add_data() with an empty input even when the drain was only
partial. decomp_uslz_add_data() replaces drain and drain_len with the new
result, so this can discard output that has not yet been forwarded.

Only call the decoder again after the previous output has been fully
drained, as the TCP decompression path already does.
---

diff --git a/src/flt_decomp.c b/src/flt_decomp.c
index 670095845..8c1823439 100644
--- a/src/flt_decomp.c
+++ b/src/flt_decomp.c
@@ -382,7 +382,8 @@ static int decomp_stream_blk(struct stream *s, struct filter *f, struct channel
 		ret = decomp_stream_blk_drain(s, f, chn, NULL, NULL, 0);
 		total += ret;
 
-		if (!(st->decomp_ctx->flags & DECOMP_CTX_FL_DONE)) {
+		if (!st->decomp_ctx->drain_len &&
+		    !(st->decomp_ctx->flags & DECOMP_CTX_FL_DONE)) {
 			char *data = "";
 
 			/* ensure there isn't remaining data in the decomp state buffer: