[exim/exim] [Bug]: S=0 when using no_return_message in autoreply transport (Issue #3197)

What is the problem environment ?
---------------------------------

Exim version 4.99 #1 built 07-Jan-2026 09:44:32
Copyright ( c ) University of Cambridge, 1995 - 2018
( c ) The Exim Maintainers and contributors in ACKNOWLEDGMENTS file, 2007 - 2025
Support for : Content_Scanning Exim_filter Sieve_filter crypteq Expand_dlfunc iconv () IPv6 PAM Perl move_frozen_messages OpenSSL TLS_resume DANE DKIM DMARC DNSSEC ESMTP_Limits ESMTP_Wellknown Event I18N OCSP PIPECONNECT PRDR PROXY Queue_Ramp SPF TCP_Fast_Open Experimental_ARC
Lookups ( built-in ) : lsearch wildlsearch nwildlsearch iplsearch dbm dbmjz dbmnz dnsdb dsearch mysql passwd redis spf
Authenticators ( built-in ) : dovecot plaintext spa tls
Routers ( built-in ) : accept dnslookup ipliteral iplookup manualroute redirect queryprogram
Transports ( built-in ) : appendfile autoreply lmtp pipe smtp
Malware: f-protd f-prot6d drweb fsecure sophie clamd avast sock cmdline
Fixed never_users: 0
Configure owner: 0:0
Size of off_t: 8
Compiler: GCC [ 14.2.0 ]
Library version: Glibc: Compile: 2.41
                       Runtime: 2.41
Hints DB:
Library version: BDB: Compile: Berkeley DB 5.3.28: ( September  9, 2013 )
                      Runtime: Berkeley DB 5.3.28: ( September  9, 2013 )
Library version: OpenSSL: Compile: OpenSSL 3.5.4 30 Sep 2025
                         Runtime: OpenSSL 3.5.4 30 Sep 2025
                                : built on: Sat Nov  1 11:22:59 2025 UTC
Library version: IDN: Compile: 1.43
                     Runtime: 1.43
Library version: PCRE2: Compile: 10.46
                       Runtime: 10.46 2025-08-27
Library version: REDIS: Compile: 1 [ 2 ]
Library version: MySQL: Compile: 110803 11.8.3 [ mariadb-11.8 ]
                       Runtime: 30407 3.4.7
WHITELIST_D_MACROS unset
TRUSTED_CONFIG_LIST unset
Configuration file is /etc/exim/exim.conf

What happened?
--------------

userautoreply:
driver = autoreply
no_return_message
text = "${lookup mysql{}}"

causes the following log line

2026-02-12 15:09:56 1vqYKK-00000000eBs-2GYh => ooooo <[email protected]>;; F=<[email protected]>;; R=userautoreply T=userautoreply S=0

The S=0 is unexpected.

Relevant log output
-------------------

2026-02-12 15:09:56 1vqYKK-00000000eBs-2GYh = > ooooo <[email protected]> ;; F = <[email protected]> ;; R = userautoreply T = userautoreply S = 0

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View it on Exim Forgejo ( https://code.exim.org/exim/exim/issues/3197 ) or reply to this email directly.