feat(plugin): guard Rust-owned classes the worker has no proxy for

The worker's autoloader fell through to the real Composer source for every
Rust-owned FQCN without a proxy stub, so plugin code doing `new Filesystem()`
or subclassing `LibraryInstaller` silently ran on a second instance the Rust
side never sees. An unimplemented part of the plugin API has to fail with an
explicit error naming it, not quietly work on a disconnected copy.

The stub generator now emits a guard class for each of those FQCNs: the real
declaration, hierarchy and constants, with every constructor and method
raising an explicit error. References satisfied by the declaration alone
(`instanceof`, `X::class`, `Link::TYPE_REQUIRE`) keep working. Two FQCNs stay
resolvable to the real class, each listed with the worker-side mechanism that
makes a natively constructed instance correct.

The error had nowhere to go: `Installer::run` dropped the `Result` of both
`dispatch_script` calls, so an exception from a listener ended in exit 0.
Both propagate now, the way the exception does upstream.

Three real-plugin E2E comparisons stop at a guard and are ignored, each
naming the class it needs.

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

1 files changed, 253 insertions, 0 deletions

diff --git a/crates/shirabe-php-rpc/php/guards/Composer/Installer.php b/crates/shirabe-php-rpc/php/guards/Composer/Installer.php
new file mode 100644
index 00000000..7197f97c
--- /dev/null
+++ b/crates/shirabe-php-rpc/php/guards/Composer/Installer.php
@@ -0,0 +1,253 @@
+<?php
+
+// Generated by scripts/plugin-stub-generator; do not edit by hand.
+// Guard for Composer\Installer.
+// The Rust side owns this class and the worker has no proxy for it, so this
+// declaration shadows the real one: the constants and the hierarchy stay, while
+// constructing it or calling anything on it raises an explicit error.
+
+namespace Composer;
+
+use Composer\Advisory\AuditConfig;
+use Composer\Autoload\AutoloadGenerator;
+use Composer\DependencyResolver\LockTransaction;
+use Composer\DependencyResolver\PolicyInterface;
+use Composer\Downloader\DownloadManager;
+use Composer\EventDispatcher\EventDispatcher;
+use Composer\Filter\PlatformRequirementFilter\PlatformRequirementFilterInterface;
+use Composer\Installer\InstallationManager;
+use Composer\Installer\SuggestedPackagesReporter;
+use Composer\IO\IOInterface;
+use Composer\Package\Locker;
+use Composer\Package\RootPackageInterface;
+use Composer\Repository\InstalledRepositoryInterface;
+use Composer\Repository\PlatformRepository;
+use Composer\Repository\RepositoryInterface;
+use Composer\Repository\RepositoryManager;
+use Composer\Repository\LockArrayRepository;
+
+class Installer
+{
+    public const ERROR_NONE = 0; // no error/success state
+    public const ERROR_GENERIC_FAILURE = 1;
+    public const ERROR_NO_LOCK_FILE_FOR_PARTIAL_UPDATE = 3;
+    public const ERROR_LOCK_FILE_INVALID = 4;
+    public const ERROR_DEPENDENCY_RESOLUTION_FAILED = 2;
+    public const ERROR_AUDIT_FAILED = 5;
+    public const ERROR_TRANSPORT_EXCEPTION = 100;
+
+    public function __construct(IOInterface $io, Config $config, RootPackageInterface $package, DownloadManager $downloadManager, RepositoryManager $repositoryManager, Locker $locker, InstallationManager $installationManager, EventDispatcher $eventDispatcher, AutoloadGenerator $autoloadGenerator)
+    {
+        \ShirabeUnsupportedClass::fail(self::class, '__construct');
+    }
+
+    public function run(): int
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'run');
+    }
+
+    protected function doUpdate(InstalledRepositoryInterface $localRepo, bool $doInstall): int
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'doUpdate');
+    }
+
+    protected function extractDevPackages(LockTransaction $lockTransaction, PlatformRepository $platformRepo, array $aliases, PolicyInterface $policy, ?LockArrayRepository $lockedRepository = null): int
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'extractDevPackages');
+    }
+
+    protected function doInstall(InstalledRepositoryInterface $localRepo, bool $alreadySolved = false): int
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'doInstall');
+    }
+
+    protected function createPlatformRepo(bool $forUpdate): PlatformRepository
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'createPlatformRepo');
+    }
+
+    public static function create(IOInterface $io, Composer $composer): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'create');
+    }
+
+    public function setIgnoredTypes(array $types): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setIgnoredTypes');
+    }
+
+    public function setAllowedTypes(?array $types): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setAllowedTypes');
+    }
+
+    public function setAdditionalFixedRepository(RepositoryInterface $additionalFixedRepository): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setAdditionalFixedRepository');
+    }
+
+    public function setTemporaryConstraints(array $constraints): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setTemporaryConstraints');
+    }
+
+    public function setDryRun(bool $dryRun = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setDryRun');
+    }
+
+    public function isDryRun(): bool
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'isDryRun');
+    }
+
+    public function setDownloadOnly(bool $downloadOnly = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setDownloadOnly');
+    }
+
+    public function setPreferSource(bool $preferSource = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setPreferSource');
+    }
+
+    public function setPreferDist(bool $preferDist = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setPreferDist');
+    }
+
+    public function setOptimizeAutoloader(bool $optimizeAutoloader): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setOptimizeAutoloader');
+    }
+
+    public function setClassMapAuthoritative(bool $classMapAuthoritative): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setClassMapAuthoritative');
+    }
+
+    public function setApcuAutoloader(bool $apcuAutoloader, ?string $apcuAutoloaderPrefix = null): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setApcuAutoloader');
+    }
+
+    public function setUpdate(bool $update): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setUpdate');
+    }
+
+    public function setInstall(bool $install): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setInstall');
+    }
+
+    public function setDevMode(bool $devMode = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setDevMode');
+    }
+
+    public function setDumpAutoloader(bool $dumpAutoloader = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setDumpAutoloader');
+    }
+
+    public function setRunScripts(bool $runScripts = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setRunScripts');
+    }
+
+    public function setConfig(Config $config): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setConfig');
+    }
+
+    public function setVerbose(bool $verbose = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setVerbose');
+    }
+
+    public function isVerbose(): bool
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'isVerbose');
+    }
+
+    public function setIgnorePlatformRequirements($ignorePlatformReqs): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setIgnorePlatformRequirements');
+    }
+
+    public function setPlatformRequirementFilter(PlatformRequirementFilterInterface $platformRequirementFilter): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setPlatformRequirementFilter');
+    }
+
+    public function setUpdateMirrors(bool $updateMirrors): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setUpdateMirrors');
+    }
+
+    public function setUpdateAllowList(array $packages): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setUpdateAllowList');
+    }
+
+    public function setUpdateAllowTransitiveDependencies(int $updateAllowTransitiveDependencies): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setUpdateAllowTransitiveDependencies');
+    }
+
+    public function setPreferStable(bool $preferStable = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setPreferStable');
+    }
+
+    public function setPreferLowest(bool $preferLowest = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setPreferLowest');
+    }
+
+    public function setMinimalUpdate(bool $minimalUpdate = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setMinimalUpdate');
+    }
+
+    public function setWriteLock(bool $writeLock = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setWriteLock');
+    }
+
+    public function setExecuteOperations(bool $executeOperations = true): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setExecuteOperations');
+    }
+
+    public function setAudit(bool $audit): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setAudit');
+    }
+
+    public function setErrorOnAudit(bool $errorOnAudit): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setErrorOnAudit');
+    }
+
+    public function setAuditFormat(string $auditFormat): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setAuditFormat');
+    }
+
+    public function setAuditConfig(AuditConfig $auditConfig): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setAuditConfig');
+    }
+
+    public function disablePlugins(): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'disablePlugins');
+    }
+
+    public function setSuggestedPackagesReporter(SuggestedPackagesReporter $suggestedPackagesReporter): self
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'setSuggestedPackagesReporter');
+    }
+}