Commit 9bbd6d585a for openssl.org

commit 9bbd6d585a164d2272bf7b354e80fb03bd5fccd7
Author: Mounir IDRASSI <mounir.idrassi@idrix.fr>
Date:   Fri Aug 14 15:00:59 2026 +0900

    test: keep QUIC RADIX diagnostics out of TAP pipe

    quic_radix_test emits several MiB of diagnostics on stderr even when
    it succeeds. In #32128 the process was observed blocked in fwrite()
    while writing this output to its inherited stderr pipe.

    As a targeted workaround, redirect stderr to a log during non-verbose
    harness runs. If the test fails, replay diagnostics from at most the
    final 32 KiB and report the log path. This preserves useful failure
    context without feeding the full multi-megabyte log back through the
    TAP pipe. Verbose and direct recipe runs remain unchanged.

    This removes the observed writer-side backpressure point without
    changing general harness behavior. The reason the harness reader
    stopped making progress remains unknown.

    Related to #32128

    Assisted-by: Codex:gpt-5.6-sel

    Reviewed-by: Neil Horman <nhorman@openssl.org>
    Reviewed-by: Saša Nedvědický <sashan@openssl.org>
    MergeDate: Mon Aug 17 20:19:49 2026
    (Merged from https://github.com/openssl/openssl/pull/32395)

diff --git a/test/recipes/70-test_quic_radix.t b/test/recipes/70-test_quic_radix.t
index f32d2f6920..9250a2b0df 100644
--- a/test/recipes/70-test_quic_radix.t
+++ b/test/recipes/70-test_quic_radix.t
@@ -1,14 +1,50 @@
 #! /usr/bin/env perl
-# Copyright 2024-2025 The OpenSSL Project Authors. All Rights Reserved.
+# Copyright 2024-2026 The OpenSSL Project Authors. All Rights Reserved.
 #
 # Licensed under the Apache License 2.0 (the "License").  You may not use
 # this file except in compliance with the License.  You can obtain a copy
 # in the file LICENSE in the source distribution or at
 # https://www.openssl.org/source/license.html

-use OpenSSL::Test qw/:DEFAULT srctop_file/;
+use OpenSSL::Test qw/:DEFAULT result_file srctop_file/;
 use OpenSSL::Test::Utils;

+sub diagnose_failure {
+    my ($log, $max_bytes) = @_;
+    my $fh;
+
+    diag("Full stderr: $log");
+    if (!open($fh, "<", $log)) {
+        diag("Could not open stderr log: $!");
+        return;
+    }
+
+    binmode($fh);
+    my $size = -s $fh;
+    if (!defined($size)) {
+        diag("Could not determine stderr log size: $!");
+        close($fh);
+        return;
+    }
+
+    my $offset = $size > $max_bytes ? $size - $max_bytes : 0;
+    if (!seek($fh, $offset, 0)) {
+        diag("Could not seek in stderr log: $!");
+        close($fh);
+        return;
+    }
+
+    # Do not start the diagnostic output with a truncated line.
+    scalar <$fh> if $offset > 0;
+
+    diag("Stderr tail (up to " . ($max_bytes / 1024) . " KiB):");
+    while (my $line = <$fh>) {
+        $line =~ s/\r?\n\z//;
+        diag($line);
+    }
+    close($fh);
+}
+
 setup("test_quic_radix");

 plan skip_all => "QUIC protocol is not supported by this OpenSSL build"
@@ -16,6 +52,13 @@ plan skip_all => "QUIC protocol is not supported by this OpenSSL build"

 plan tests => 1;

-ok(run(test(["quic_radix_test",
-             srctop_file("test", "certs", "servercert.pem"),
-             srctop_file("test", "certs", "serverkey.pem")])));
+# Keep the test's multi-megabyte diagnostics out of the TAP pipe.
+my $redirect = $ENV{HARNESS_ACTIVE} && !$ENV{HARNESS_VERBOSE};
+my $stderr_log = result_file("quic_radix_test.log");
+my $result = run(test(["quic_radix_test",
+                       srctop_file("test", "certs", "servercert.pem"),
+                       srctop_file("test", "certs", "serverkey.pem")],
+                      $redirect ? (stderr => $stderr_log) : ()));
+
+diagnose_failure($stderr_log, 32 * 1024) if !$result && $redirect;
+ok($result, "running QUIC RADIX tests");