feat(phase-c): resolve reflection/downcast phase-b TODOs

Resolve category F phase-b TODOs (class-string, instanceof, get_class,
method_exists, __FILE__, Reflection API, downcast).

- VcsRepository: dispatch drivers through a VcsDriverKind enum
  (instantiate/supports/php_class_name) and add constructors to the
  concrete VCS drivers
- repository downcasts via RepositoryInterfaceHandle::downcast_rc and
  as_any (init/show commands, vcs ValidatingArrayLoader)
- BaseCommand::is_self_update_command override replaces an instanceof
- Factory::create narrows PartialComposer to ComposerHandle via as_full
- InstalledVersions gains set_self_dir/set_installed_is_local_dir,
  replacing Reflection-based static property mutation
- ClassLoader::as_array_iter ports the PHP (array) cast
- drop the unnecessary __FILE__ phar branch in self-update

application get_class(command) reclassified TODO(plugin); buffer_io
StreamableInputInterface downcast and the ValidatingArrayLoader trait
redesign left as tracked TODOs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

1 files changed, 7 insertions, 8 deletions

diff --git a/crates/shirabe/src/factory.rs b/crates/shirabe/src/factory.rs
index ac7c055..c9de808 100644
--- a/crates/shirabe/src/factory.rs
+++ b/crates/shirabe/src/factory.rs
@@ -15,7 +15,7 @@ use shirabe_php_shim::{
 
 use crate::autoload::AutoloadGenerator;
 use crate::cache::Cache;
-use crate::composer::{ComposerWeakHandle, PartialOrFullComposer};
+use crate::composer::{ComposerHandle, ComposerWeakHandle, PartialOrFullComposer};
 use crate::composer::{PartialComposerHandle, PartialComposerWeakHandle};
 use crate::config::Config;
 use crate::config::JsonConfigSource;
@@ -1262,7 +1262,7 @@ impl Factory {
         config: Option<LocalConfigInput>,
         disable_plugins: DisablePlugins,
         disable_scripts: bool,
-    ) -> anyhow::Result<PartialComposerHandle> {
+    ) -> anyhow::Result<ComposerHandle> {
         let factory = Self;
 
         // for BC reasons, if a config is passed in either as array or a path that is not the default composer.json path
@@ -1285,14 +1285,13 @@ impl Factory {
 
         let composer =
             factory.create_composer(io, config, disable_plugins, None, true, disable_scripts)?;
-        if !composer.is_full() {
-            // TODO(phase-b): unreachable when fullLoad=true; downcasting needs design.
-            return Err(anyhow::anyhow!(RuntimeException {
+        // fullLoad=true guarantees a full Composer; narrow PartialComposer -> Composer (PHP `: Composer`).
+        composer.as_full().ok_or_else(|| {
+            anyhow::anyhow!(RuntimeException {
                 message: "Composer expected with fullLoad=true".to_string(),
                 code: 0,
-            }));
-        }
-        Ok(composer)
+            })
+        })
     }
 
     /// If you are calling this in a plugin, you probably should instead use `$composer->getLoop()->getHttpDownloader()`