Regression: highlight_string() HTML still lacks Zend <pre> wrapper / uses nbsp (re-#10308, ext/standard/highlight.c) #23733

Category

Stdlib · php-src-strict · highlight_string · pillar 4

Problem

highlight_string('<?php echo 1;', true) still diverges from Zend markup. #10308 / #12401 closed earlier; still red on master 2026-07-27 vs Zend 8.4.23.

php-src reference

• php/php-src ext/standard/highlight.c — php_highlight / HTML emitter
• php/php-src ext/standard/basic_functions.c — highlight_string
• Prior: Stdlib: highlight_string() HTML markup wrong vs Zend — output length/spans differ (ext/standard/basic_functions.c) #10308, Regression: highlight_string() string literals use #0000BB not Zend #DD0000 (ext/standard/php_highlight.h, re-#10308) #12401, Stdlib: highlight_file() emits raw newlines not <br /> between lines (ext/standard/highlight.c) #17557

PHP implementation target

• ext/standard/ highlight implementation — match Zend wrapper (<pre><code style=…>), span colors, and space (not  ) emission for this input
• PHP-in-PHP; keep tokenizer path without growing runtime/ C

Repro

./script/docker-exec.sh -- bash -lc 'cat > /tmp/hl.php <<'"'"'PHP'"'"'
<?php
echo highlight_string("<?php echo 1;", true), "\n";
PHP
php bin/vm.php /tmp/hl.php'
# Compare to: docker run --rm -i \$HARNESS_DOCKER_RUN_OPTS --entrypoint php php:8.4-cli /dev/stdin < /tmp/hl.php

Done when

• highlight_string(..., true) byte-matches Zend 8.4 for the <?php echo 1; smoke (wrapper + spaces)
• highlight_file / show_source stay consistent with the same emitter
• Compliance .phpt under test/compliance/cases/
• php-src-strict; no php-compiler-strict shortcut