feat(php-shim): give ported exceptions PHP's class hierarchy

Ported exceptions were flat structs reached with `downcast_ref`, so
Composer's `catch (\RuntimeException $e)` only matched the exact leaf
type and `get_class($e)` had nothing to report. Each exception now
embeds an instance of the class it extends and travels inside an
`AnyThrowable`; `Catch::catch`/`catch_mut` walk that chain, and
`PhpClass::php_class_name` yields the PHP FQCN.

Dropping the `std::error::Error` impls from the exception types leaves
`AnyThrowable` as the only route into an `anyhow::Error`, so the walk
cannot be bypassed. A `no_exception_downcast` linter catches the
`downcast::<X>()` calls that would now silently answer `None`.

Three sites change behavior as a result: the `TransportException`
exit-code override reaches `MaxFileSizeExceededException`, the
`catch (\LogicException)` in findSimilar() reaches its subclasses, and
rendered exception titles carry the real class name rather than a
guess. `get_class_err()` is no longer a `todo!()`, which re-enables
FilesystemRepositoryTest::testCorruptedRepositoryFile.

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

1 files changed, 13 insertions, 8 deletions

diff --git a/crates/shirabe/src/repository/vcs/vcs_driver.rs b/crates/shirabe/src/repository/vcs/vcs_driver.rs
index 3321201c..42f679df 100644
--- a/crates/shirabe/src/repository/vcs/vcs_driver.rs
+++ b/crates/shirabe/src/repository/vcs/vcs_driver.rs
@@ -13,6 +13,7 @@ use crate::util::http::Response;
 use chrono::{DateTime, FixedOffset};
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::Preg;
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{DATE_RFC3339, PhpMixed, extension_loaded, php_regex};
 
 #[derive(Debug)]
@@ -66,7 +67,7 @@ impl VcsDriverBase {
         "http"
     }
 
-    pub fn get_contents(&self, url: &str) -> anyhow::Result<Response, TransportException> {
+    pub fn get_contents(&self, url: &str) -> anyhow::Result<Response, Box<TransportException>> {
         let options_mixed = self
             .repo_config
             .get("options")
@@ -79,9 +80,11 @@ impl VcsDriverBase {
         self.http_downloader
             .borrow_mut()
             .get(url, options)
-            .map_err(|e| match e.downcast::<TransportException>() {
-                Ok(te) => te,
-                Err(other) => TransportException::new(other.to_string(), 0),
+            .map_err(|e| {
+                Box::new(match e.catch::<TransportException>() {
+                    Some(te) => te.clone(),
+                    None => TransportException::new(e.to_string(), 0),
+                })
             })
     }
 
@@ -299,7 +302,7 @@ pub trait VcsDriver: VcsDriverInterface {
         "http"
     }
 
-    fn get_contents(&self, url: &str) -> anyhow::Result<Response, TransportException> {
+    fn get_contents(&self, url: &str) -> anyhow::Result<Response, Box<TransportException>> {
         let options_mixed = self
             .repo_config()
             .get("options")
@@ -312,9 +315,11 @@ pub trait VcsDriver: VcsDriverInterface {
         self.http_downloader()
             .borrow_mut()
             .get(url, options)
-            .map_err(|e| match e.downcast::<TransportException>() {
-                Ok(te) => te,
-                Err(other) => TransportException::new(other.to_string(), 0),
+            .map_err(|e| {
+                Box::new(match e.catch::<TransportException>() {
+                    Some(te) => te.clone(),
+                    None => TransportException::new(e.to_string(), 0),
+                })
             })
     }