Add PHP 5.2 WebAssembly builds and runtime support

[JanJakes]

Summary

• Introduce LegacyPHPVersions / AllPHPVersions type system and register PHP 5.2.17 in the version registry
• Add Dockerfile and C-source changes for PHP 5.2 compilation: autoconf 2.13, pre-generated parser/scanner downloads, flex wrapper, polyfill extension compat (ZEND_FE_END/PHP_FE_END), yytext duplicate-definition handling, mysqlnd gating, CLI getopt linking, php_cli_process_title version guard
• Commit pre-built PHP 5.2 WASM binaries for all four targets (web/node × JSPI/Asyncify)
• Wire PHP 5.2 into the web worker and CLI: legacy PHP ini pre-creation (disables ini_get_all, OPcache), single-instance mode for PROXYFS, correct SQLite plugin selection, extension gating, PHP 5.2-compatible mu-plugin stub
• Support downloading non-minified legacy WordPress versions from wordpress.org (1.0–6.2)

Test plan

• npx nx recompile-php:jspi php-wasm-web -- --PHP_VERSION=5.2 succeeds
• npx nx recompile-php:asyncify php-wasm-web -- --PHP_VERSION=5.2 succeeds
• npx nx recompile-php:jspi php-wasm-node -- --PHP_VERSION=5.2 succeeds
• npx nx recompile-php:asyncify php-wasm-node -- --PHP_VERSION=5.2 succeeds
• npx nx typecheck playground-website passes
• npx nx run-many -t lint --projects=php-wasm-web,php-wasm-node,php-wasm-universal,playground-website passes

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Note

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Adds PHP 5.2.17 as a “legacy” WebAssembly runtime across web + node, and wires it through Playground (worker + CLI) to support booting older WordPress versions.

Changes:

• Introduces legacy PHP version typing/registry, loader-module wiring, and pre-boot php.ini handling for PHP 5.2.
• Adds new @php-wasm/*-5-2 build packages (web/node) plus runtime guards for unsupported extensions / multi-instance behavior.
• Updates Playground boot flow for legacy WP/PHP constraints (WP zip sourcing, SQLite plugin selection, mu-plugin stubs, WP_DEBUG gating).

Reviewed changes

Copilot reviewed 50 out of 60 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
tsconfig.base.json	Adds TS path aliases for new @php-wasm/*-5-2 packages.
packages/playground/remote/src/lib/playground-worker-endpoint.ts	Limits instances for legacy PHP and swaps mu-plugin stub for PHP 5.2.
packages/playground/remote/src/lib/playground-worker-endpoint-blueprints-v1.ts	Downloads non-minified WP from wordpress.org; selects legacy SQLite; gates WP_DEBUG.
packages/playground/remote/src/lib/playground-mu-plugin/playground-includes/wp_http_fetch.php	Replaces null-coalescing for PHP 5.2 compatibility.
packages/playground/remote/src/lib/playground-mu-plugin/0-playground.php	Adds PHP/WP version guards and PHP-5.2-safe fallbacks.
packages/playground/remote/src/lib/playground-mu-plugin/0-playground-php52.php	Adds PHP 5.2-compatible mu-plugin stub (named callbacks + dummy transport).
packages/playground/client/src/blueprints-v1-handler.ts	Skips update-check prefetch for legacy WordPress versions.
packages/playground/cli/tests/run-cli.spec.ts	Adjusts tests to avoid legacy WP versions in “supported” CLI boot test.
packages/playground/cli/src/run-cli.ts	Accepts legacy PHP versions; gates WP_DEBUG defaults/extensions for legacy; adds loader logic tweaks.
packages/playground/cli/src/blueprints-v1/worker-thread-v1.ts	Passes phpVersion through V1 worker boot and request-handler creation.
packages/playground/cli/src/blueprints-v1/download.ts	Allows selecting SQLite integration zip version (including php52 variant).
packages/playground/cli/src/blueprints-v1/blueprints-v1-handler.ts	Selects legacy SQLite integration zip for legacy PHP; passes phpVersion to worker boot.
packages/playground/blueprints/src/lib/v1/types.ts	Expands Blueprint PHP version typing to include legacy PHP.
packages/playground/blueprints/src/lib/v1/compile.ts	Uses AllPHPVersions for compilation-time version selection.
packages/playground/blueprints/src/lib/types.ts	Updates RuntimeConfiguration to AllPHPVersion.
packages/playground/blueprints/public/blueprint-schema.json	Adds LegacyPHPVersion/AllPHPVersion to schema and references them.
packages/php-wasm/web/src/lib/load-runtime.ts	Supports legacy php.ini preRun and throws on intl with legacy PHP.
packages/php-wasm/web/src/lib/get-php-loader-module.ts	Adds dynamic import for @php-wasm/web-5-2.
packages/php-wasm/web-builds/5-2/tsconfig.lib.json	New TS config for @php-wasm/web-5-2 build.
packages/php-wasm/web-builds/5-2/tsconfig.json	New TS project references for web 5.2 package.
packages/php-wasm/web-builds/5-2/src/index.ts	Implements JSPI/Asyncify loader selection for web PHP 5.2.
packages/php-wasm/web-builds/5-2/project.json	Nx targets for building/publishing web PHP 5.2 binaries.
packages/php-wasm/web-builds/5-2/package.json	Defines new @php-wasm/web-5-2 package metadata/exports.
packages/php-wasm/web-builds/5-2/build.js	esbuild bundling script for web PHP 5.2 package.
packages/php-wasm/universal/src/lib/supported-php-versions.ts	Adds legacy/all version lists + type guard isLegacyPHPVersion.
packages/php-wasm/universal/src/lib/proxy-file-system.ts	Skips PROXYFS mmap patch for legacy PHP instances due to parser bug.
packages/php-wasm/universal/src/lib/legacy-php-ini.ts	Adds legacy PHP pre-boot php.ini + preRun writer.
packages/php-wasm/universal/src/lib/index.ts	Re-exports legacy version helpers and legacy ini helpers.
packages/php-wasm/supported-php-versions.mjs	Registers PHP 5.2.17 in version metadata list.
packages/php-wasm/node/src/lib/load-runtime.ts	Supports legacy php.ini preRun and rejects extensions on legacy PHP.
packages/php-wasm/node/src/lib/get-php-loader-module.ts	Adds dynamic import for @php-wasm/node-5-2.
packages/php-wasm/node/src/lib/extensions/memcached/get-memcached-extension-module.ts	Refactors imports formatting (no functional change).
packages/php-wasm/node-builds/5-2/tsconfig.lib.json	New TS config for @php-wasm/node-5-2 build.
packages/php-wasm/node-builds/5-2/tsconfig.json	New TS project references for node 5.2 package.
packages/php-wasm/node-builds/5-2/src/index.ts	Implements JSPI/Asyncify loader selection for node PHP 5.2; stubs extension paths.
packages/php-wasm/node-builds/5-2/project.json	Nx targets for building/publishing node PHP 5.2 binaries.
packages/php-wasm/node-builds/5-2/package.json	Defines new @php-wasm/node-5-2 package metadata/exports.
packages/php-wasm/node-builds/5-2/build.js	esbuild bundling script for node PHP 5.2 package.
packages/php-wasm/compile/php/proc_open.h	Adds include guard and PHP 5.x pipe type compatibility.
packages/php-wasm/compile/php/proc_open.c	Adds PHP 5.x stub implementation for proc_* APIs.
packages/php-wasm/compile/php/php_wasm.c	Adds PHP-version guards for headers/APIs and PHP 5.x compatibility fixes.
packages/php-wasm/compile/php/php5.2.patch	Adds PHP 5.2 fixes (empty copy() crash; libxml buffer accessors).
packages/php-wasm/compile/php/php5.2-openssl-compat.patch	Adds OpenSSL 1.1+ compatibility shims for PHP 5.2 openssl extension.
packages/php-wasm/compile/php/apply-mysqlnd-patch.sh	Tolerates missing mysqlnd in older PHP versions; improves messaging/failure behavior.
packages/php-wasm/compile/php/Dockerfile	Adds PHP 5.2-specific build steps (autoconf 2.13, parser sources, flags, feature gating).
packages/php-wasm/compile/php-wasm-memory-storage/wasm_memory_storage.c	Disables custom memory storage for PHP < 7 with no-op init/shutdown.
packages/php-wasm/compile/php-wasm-dns-polyfill/dns_polyfill.h	Moves arginfo definitions out of header (compat).
packages/php-wasm/compile/php-wasm-dns-polyfill/dns_polyfill.c	Adds PHP 5.2 compat for macros/TSRMLS and restores arginfo definitions.
packages/php-wasm/compile/php-post-message-to-js/post_message_to_js.h	Moves arginfo definitions out of header (compat).
packages/php-wasm/compile/php-post-message-to-js/post_message_to_js.c	Adds PHP 5.2 compat for macros/TSRMLS and return handling.

Comments suppressed due to low confidence (1)

packages/php-wasm/node/src/lib/load-runtime.ts:1

• Setting preRun: ... : undefined after spreading options.emscriptenOptions overwrites any caller-supplied preRun hook (even for non-legacy PHP), and for legacy PHP it replaces rather than appends to existing preRun steps. Prefer preserving existing preRun(s) and only adding createLegacyPhpIniPreRunStep() when legacy (e.g., normalize the existing preRun into an array, append the legacy step, and avoid writing preRun: undefined for non-legacy).

import {

---

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[adamziel]

should we remove closures from 0-playground.php and use the same file everywhere? Or would that just complicate things?

[JanJakes]

Claude's opinion:

The two files serve quite different environments, not just different PHP syntax:

0-playground.php (PHP 5.3+, modern WP) has login message, networking-disabled admin UI, link rewriting, URL reporting to parent frame, pattern picker disable, client-side media disable, Fetch or Dummy HTTP transport, uses \WpOrg\Requests\Requests (namespaced, PHP 5.3+), uses str_ends_with (PHP 8.0+), and 9 closures.

0-playground-php52.php (PHP 5.2, old WP) has Dummy HTTP transport only (the fetch transport files use PHP 5.3+ syntax), WP Cron disable, uses class_exists('Requests') (no namespace), and uses substr instead of str_ends_with.

Removing closures is the easy part — just convert to named functions. The hard part is that most features in the main file don't apply to PHP 5.2 + old WordPress:

• get_current_user_id() may not exist in WP 2.x
• The networking UI assumes modern admin screens
• str_ends_with is PHP 8.0+
• The Requests namespace class is PHP 5.3+
• Fetch transport files themselves won't parse on PHP 5.2

Unifying would mean wrapping most of the file in version_compare guards, making it harder to read than having two separate files. Keeping them separate seems cleaner given how different the two environments are.

[adamziel]

should we support PHP 5.2 in that plugin? Or have a branch where Rector automatically downgrades the codebase to 5.2?

[JanJakes]

@adamziel This is now in #3490. It appears that the split into two PRs was imperfect. Rector has no rules to downgrade below PHP 7.2, so the agent wrote its own logic using PHP parsers and some more patches. We could move it to the SQLite repo later, I guess that would make sense.

[adamziel]

Is it legacy PHP, or is it us? Those sites worked back then, perhaps proxyfs is flawed? I think we can merge this PR as is, but wdyt about rephrasing this comment and getting some long-running agent to identify the root cause?

[JanJakes]

Addressed in 1add040.

[JanJakes]

Actually, this was incorrectly distilled from the previous 5.6 attempts. The correct fix is already done. Improved in 5f425d4 + 99c1b66.

[adamziel]

Looks great! My only real concern was the pointer cast thing and it appears like EMULATE_POINTER_CASTS solved that. I'm still concerned about the overhead part of it:

Use EMULATE_FUNCTION_POINTER_CASTS. When you build with -sEMULATE_FUNCTION_POINTER_CASTS, Emscripten emits code to emulate function pointer casts at runtime, adding extra arguments/dropping them/changing their type/adding or dropping a return type/etc. This can add significant runtime overhead, so it is not recommended, but is worth trying.

It would be interesting to measure that somehow and explore alternatives if anything is significantly slower. That's not a blocker here at all. Thank you @JanJakes!

[mho22]

Looks great! My only real concern was the pointer cast thing and it appears like EMULATE_POINTER_CASTS solved that. I'm still concerned about the overhead part of it:

@adamziel EMULATE_FUNCTION_POINTER_CASTS was removed from the PHP Dockerfile. So there is no potential overhead anymore.

[mho22]

We could use the same approach as for node/load-runtime.ts with :

	if (
		isLegacy &&
		(loaderOptions?.withIntl)
	) {
		throw new Error(
			`Extensions (intl) are not ` +
				`available for legacy PHP ${phpVersion}.`
		);
	}
	
	if (!isLegacy) {
	....

maybe?

[JanJakes]

Addressed in 04c7b03.

[adamziel]

The failing test looks like a flake, let's ship!

[mho22]

It looks like the implementation of TSRMLS_CC breaks the PHP.wasm Node 8.5 compilation. I am working on a fix.