Document PHP 7.4 WASM limitation

Author: adamziel

.github/workflows/wasm-spike.yml

@@ -27,6 +27,8 @@ jobs:
       fail-fast: false
       max-parallel: 1
       matrix:
+        # The Rust WASM path uses ext-php-rs 0.15, which depends on PHP 8
+        # Zend APIs. PHP 7.4 cannot be added here by extending the matrix.
         php: ['8.5', '8.4', '8.3', '8.2', '8.1', '8.0']
         async-mode: ['jspi']
 

packages/php-ext-wp-mysql-parser/README.md

@@ -30,3 +30,12 @@ Load it for local test runs with:
 ```bash
 php -d extension=/path/to/libwp_mysql_parser.so vendor/bin/phpunit
 ```
+
+## PHP.wasm side-module build
+
+The experimental PHP.wasm side-module build lives in `wasm-spike/` and is
+verified in CI for PHP `8.0` through `8.5`.
+
+PHP `7.4` is not supported by this Rust WASM path. The build uses
+`ext-php-rs` `0.15`, which depends on PHP 8 Zend APIs and does not compile
+against PHP `7.4` headers.

packages/php-ext-wp-mysql-parser/wasm-spike/RESULT.md

@@ -9,6 +9,14 @@ through Playground's compile-extension test harness and running a native lexer
 smoke test. PHP 7.4 is outside this Rust path because `ext-php-rs` 0.15
 depends on PHP 8 Zend APIs and does not compile against PHP 7.4 headers.
 
+## PHP version scope
+
+This spike intentionally builds only PHP 8.0 through PHP 8.5. Adding PHP 7.4
+would require a different binding layer, or real PHP 7.4 support in
+`ext-php-rs`; it is not a workflow-only change. The failures are in the
+generated/wrapped Zend API surface itself, including PHP 8-only symbols and
+struct fields.
+
 The build uses the upstream Playground compile-extension tooling for the
 phpize side-module build, static archive force-linking, wasm-opt pass, and
 manifest generation. The local glue that remains is Rust-specific: build

packages/php-ext-wp-mysql-parser/wasm-spike/build-in-docker-rust.sh

@@ -36,8 +36,14 @@ case "$PHP_VERSION" in
   8.3) PHP_API_VERSION=20230831 ;;
   8.4) PHP_API_VERSION=20240924 ;;
   8.5) PHP_API_VERSION=20250925 ;;
+  7.4)
+    echo "Unsupported PHP_VERSION: 7.4" >&2
+    echo "The WASM Rust build uses ext-php-rs 0.15, which depends on PHP 8 Zend APIs and does not compile against PHP 7.4 headers." >&2
+    exit 1
+    ;;
   *)
-    echo "Unsupported PHP_VERSION: $PHP_VERSION" >&2
+    echo "Unsupported PHP_VERSION: $PHP_VERSION. Supported values: 8.0, 8.1, 8.2, 8.3, 8.4, 8.5." >&2
+    echo "PHP 7.4 is outside this WASM Rust path because ext-php-rs 0.15 requires PHP 8 Zend APIs." >&2
     exit 1
     ;;
 esac