fix(event-dispatcher): let a PHP script reach the Composer object graph

A PHP script listener that walks the event it receives (Laravel's
Illuminate\Foundation\ComposerScripts::postAutoloadDump asks for
$event->getComposer()->getConfig()->get('vendor-dir')) aborted the run
with `unknown Rust handle 2`.

The event's getComposer/getIO answers register an entity in the R table
and hand back its rhandle, but ScriptRpcDispatcher resolved only rhandle
0 and the one event handle of the call in flight, so it could not serve a
method on a handle it had just minted itself. The R-table lookup
PluginRpcDispatcher already does is now dispatch_r_table_method, shared
by both.

The stubs that graph hands out extend and implement the real Composer
contracts (Composer\Package\PackageInterface and the rest), which live in
the Composer PHP runtime and not among the generated stubs or guards, so
execute_event_php_script loads that runtime the way the plugin and
command-class paths do.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

4 files changed, 130 insertions, 0 deletions

diff --git a/crates/shirabe/tests/plugin/e2e_script_event_test.rs b/crates/shirabe/tests/plugin/e2e_script_event_test.rs
new file mode 100644
index 00000000..5a0267d7
--- /dev/null
+++ b/crates/shirabe/tests/plugin/e2e_script_event_test.rs
@@ -0,0 +1,90 @@
+//! Script event E2E compatibility check: upstream Composer and Shirabe each run `dump-autoload`
+//! in a fixture project whose `post-autoload-dump` script is a PHP static method, and the method
+//! records what the `Composer\Script\Event` it receives exposes. Upstream has no test that reads
+//! the Composer object graph out of an event from a script, so the whole fixture is
+//! Shirabe-authored (`fixtures/e2e-script-event/`) and nothing has to be fetched; the test skips
+//! only while the PHP runtime or the Composer checkout is missing.
+
+use crate::e2e_extension_installer_test::{copy_dir, upstream_composer_bin};
+use crate::php_worker::{lock_php_worker, php_runtime_available};
+use std::path::{Path, PathBuf};
+use tempfile::TempDir;
+
+fn fixture_dir() -> PathBuf {
+    Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/plugin/fixtures/e2e-script-event")
+}
+
+struct Run {
+    exit_code: i32,
+    trace: String,
+    stdout: String,
+}
+
+/// Runs `dump-autoload` in a fresh copy of the fixture and returns the exit code with what the
+/// script wrote to its trace file and through the event's IO.
+fn dump_autoload(program: &str, prefix_args: &[&str]) -> Run {
+    let work = TempDir::new().unwrap();
+    copy_dir(&fixture_dir(), work.path());
+    let project = work.path().join("project");
+    let output = std::process::Command::new(program)
+        .args(prefix_args)
+        .arg("dump-autoload")
+        .current_dir(&project)
+        .env("COMPOSER_HOME", work.path().join("home"))
+        .env("COMPOSER_CACHE_DIR", work.path().join("cache"))
+        .env("COMPOSER_NO_INTERACTION", "1")
+        .env("COLUMNS", "120")
+        .env("LINES", "30")
+        .output()
+        .unwrap();
+    Run {
+        exit_code: output.status.code().unwrap_or(-1),
+        trace: std::fs::read_to_string(project.join("script-event-trace.txt")).unwrap_or_default(),
+        stdout: String::from_utf8_lossy(&output.stdout).into_owned(),
+    }
+}
+
+#[test]
+fn test_script_event_object_graph_matches_upstream_composer() {
+    if !php_runtime_available() {
+        return;
+    }
+    let Some(composer_bin) = upstream_composer_bin() else {
+        return;
+    };
+    let _worker = lock_php_worker();
+    let composer_bin = composer_bin.to_str().unwrap().to_string();
+
+    let upstream = dump_autoload("php", &[composer_bin.as_str()]);
+    let shirabe = dump_autoload(env!("CARGO_BIN_EXE_shirabe"), &[]);
+
+    assert_eq!(0, upstream.exit_code, "upstream dump-autoload must succeed");
+    assert_eq!(upstream.exit_code, shirabe.exit_code);
+    assert_eq!(upstream.trace, shirabe.trace);
+
+    // Pinned as well as compared, so a run where neither side dispatches the script cannot pass.
+    assert_eq!(
+        "\
+event=post-autoload-dump
+dev=0
+root=shirabe/e2e-script-event
+vendor-dir=vendor
+bin-dir=bin
+",
+        upstream.trace
+    );
+
+    let io_line = |run: &Run| -> String {
+        run.stdout
+            .lines()
+            .find(|line| line.starts_with("script-event: "))
+            .unwrap_or_default()
+            .to_string()
+    };
+    assert_eq!(io_line(&upstream), io_line(&shirabe));
+    assert_eq!(
+        "script-event: event=post-autoload-dump dev=0 root=shirabe/e2e-script-event \
+         vendor-dir=vendor bin-dir=bin",
+        io_line(&upstream)
+    );
+}
diff --git a/crates/shirabe/tests/plugin/fixtures/e2e-script-event/project/composer.json b/crates/shirabe/tests/plugin/fixtures/e2e-script-event/project/composer.json
new file mode 100644
index 00000000..59fc8f13
--- /dev/null
+++ b/crates/shirabe/tests/plugin/fixtures/e2e-script-event/project/composer.json
@@ -0,0 +1,17 @@
+{
+    "name": "shirabe/e2e-script-event",
+    "description": "E2E fixture project: record what a post-autoload-dump PHP script sees on its Event.",
+    "repositories": [
+        {
+            "packagist.org": false
+        }
+    ],
+    "autoload": {
+        "psr-4": {
+            "Shirabe\\E2e\\": "src/"
+        }
+    },
+    "scripts": {
+        "post-autoload-dump": "Shirabe\\E2e\\ScriptEventRecorder::postAutoloadDump"
+    }
+}
diff --git a/crates/shirabe/tests/plugin/fixtures/e2e-script-event/project/src/ScriptEventRecorder.php b/crates/shirabe/tests/plugin/fixtures/e2e-script-event/project/src/ScriptEventRecorder.php
new file mode 100644
index 00000000..84fa0da9
--- /dev/null
+++ b/crates/shirabe/tests/plugin/fixtures/e2e-script-event/project/src/ScriptEventRecorder.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace Shirabe\E2e;
+
+use Composer\Script\Event;
+
+class ScriptEventRecorder
+{
+    public static function postAutoloadDump(Event $event): void
+    {
+        $composer = $event->getComposer();
+        $lines = [
+            'event=' . $event->getName(),
+            'dev=' . ($event->isDevMode() ? '1' : '0'),
+            'root=' . $composer->getPackage()->getName(),
+            'vendor-dir=' . basename($composer->getConfig()->get('vendor-dir')),
+            'bin-dir=' . basename($composer->getConfig()->get('bin-dir')),
+        ];
+        $event->getIO()->write('script-event: ' . implode(' ', $lines));
+        file_put_contents(__DIR__ . '/../script-event-trace.txt', implode("\n", $lines) . "\n");
+    }
+}
diff --git a/crates/shirabe/tests/plugin/main.rs b/crates/shirabe/tests/plugin/main.rs
index d8defcbc..000ca3a9 100644
--- a/crates/shirabe/tests/plugin/main.rs
+++ b/crates/shirabe/tests/plugin/main.rs
@@ -13,6 +13,7 @@ mod e2e_installers_test;
 mod e2e_normalize_test;
 mod e2e_package_event_test;
 mod e2e_script_command_test;
+mod e2e_script_event_test;
 mod plugin_installer_test;
 mod subscriber_test;
 mod value_round_trip_test;