Stdlib: mail() — send message via sendmail/MTA (ext/standard/mail.c parity)

[PurHur]

Category

stdlib

Problem

mail() is missing. Many PHP apps use it for simple outbound email (web forms, alerts). php-src implements it in ext/standard (not a separate extension).

function_exists('mail') is false under bin/vm.php (verified 2026-06-04).

Duplicate tracker: consolidate with #5092 — implement on this issue (#3285); close #5092 when merged.

php-src reference

• php/php-src ext/standard/mail.c — PHP_FUNCTION(mail), php_mail(), php_mail_build_headers()
• php/php-src ext/standard/headers.c — additional header validation
• php/php-src main/php_ini.c — sendmail_path, mail.add_x_header, mail.mixed_lf_and_crlf

Repro (failure today)

<?php
if (!function_exists('mail')) {
    fwrite(STDERR, "MISSING: mail\n");
    exit(1);
}
$ok = @mail(
    'user@example.com',
    'Subject',
    "Body line\n",
    "From: noreply@example.com\r\n"
);
var_export($ok);

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php8.2 -r "var_export(function_exists(\"mail\")); echo PHP_EOL;"
php bin/vm.php -r "var_export(function_exists(\"mail\")); echo PHP_EOL;"
php bin/vm.php repro.php
'

Runtime	function_exists('mail')	repro exit
Zend	true	var_export bool (may be false without MTA)
VM	false	exit 1 MISSING: mail

php-src-strict probes (after implementation)

• Non-string $to / $subject → TypeError per mail.c
• Invalid additional headers → ValueError / E_WARNING per Zend version

Scope (PHP-in-PHP)

Path	Work
ext/standard/mail.php	VM builtin; v1 delegate to host mail() when available (bootstrap), native sendmail pipe follow-up
ext/standard/Module.php	Register
Tests	test/compliance/cases/stdlib/mail_exists.phpt (existence + arg validation subset)
Matrix	script/capability-matrix.php

No permanent mail transport logic in runtime/*.c unless thin sendmail pipe ABI is unavoidable.

Done when

• function_exists('mail') true on VM
• Repro runs without MISSING: mail fatal; accepts Zend-like bool return without MTA
• At least one TypeError probe for non-string recipient matches Zend
• ./script/ci-fast.sh --filter mail_exists green
• Close Stdlib: mail() — sendmail wrapper missing from ext/standard (mail.c parity) #5092 when merged

Related

• Stdlib: openlog() / syslog() / closelog() — Unix syslog (ext/standard/syslog.c parity) #3676 syslog · Stdlib: getmxrr() — MX record lookup (ext/standard/dns.c parity) #3662 getmxrr · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

Cleanup bot: Also duplicates #3493 — #3674 was filed with the same scope. Canonical tracker for implementation: #3493.

[PurHur]

claim: PHP Compiler STD Lib Advanced — batch (issues #3285 + mail transport depth children)

Sequential PRs under ext/standard/mail.c:

1. Stdlib: mail() — send message via sendmail/MTA (ext/standard/mail.c parity) #3285 — real sendmail_path popen transport (upgrade always-false stub from Stdlib: mail() not registered on VM (ext/standard/mail.c) #12482)
2. child — additional_headers array|string + php_mail_build_headers ValueError
3. child — mail.add_x_header / X-PHP-Originating-Script
4. child — additional_params shell escape + mail.force_extra_parameters

Starting #3285.

[PurHur]

Merged #21435

Verification

• php bin/vm.php -d sendmail_path=…/mock_sendmail.sh test/repro/issue_3285_mail_sendmail.php → true / OK
• vendor/bin/phpunit test/compliance/VMTest.php --filter 'mail_sendmail_transport|mail_registered' → OK (4)
• php script/bootstrap-inventory.php --check → OK 6163/6163

Next in batch: #21432 (array headers) → #21433 (add_x_header) → #21434 (additional_params).

[PurHur]

Advanced stdlib mail transport batch (this run)

Issue	PR	Status
#3285 sendmail_path popen	#21435	merged
#21432 array headers	#21436	merged
#21433 mail.add_x_header	#21437	merged

Filed + claimed next: #21434 (mail.force_extra_parameters — escapeshellcmd for arg 5 already landed with #3285).