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, 9 insertions, 19 deletions

diff --git a/crates/shirabe/src/dependency_resolver/solver_problems_exception.rs b/crates/shirabe/src/dependency_resolver/solver_problems_exception.rs
index 39f2b2c1..4c948608 100644
--- a/crates/shirabe/src/dependency_resolver/solver_problems_exception.rs
+++ b/crates/shirabe/src/dependency_resolver/solver_problems_exception.rs
@@ -18,14 +18,6 @@ pub struct SolverProblemsException {
 impl SolverProblemsException {
     pub const ERROR_DEPENDENCY_RESOLUTION_FAILED: i64 = 2;
 
-    pub fn get_code(&self) -> i64 {
-        self.inner.code
-    }
-
-    pub fn get_message(&self) -> &str {
-        &self.inner.message
-    }
-
     pub fn new(
         problems: Vec<Problem>,
         learned_pool: Vec<Vec<std::rc::Rc<std::cell::RefCell<Rule>>>>,
@@ -35,10 +27,7 @@ impl SolverProblemsException {
             problems.len()
         );
         Self {
-            inner: RuntimeException {
-                message,
-                code: Self::ERROR_DEPENDENCY_RESOLUTION_FAILED,
-            },
+            inner: RuntimeException::with_code(message, Self::ERROR_DEPENDENCY_RESOLUTION_FAILED),
             problems,
             learned_pool,
         }
@@ -170,10 +159,11 @@ impl SolverProblemsException {
     }
 }
 
-impl std::fmt::Display for SolverProblemsException {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.inner.message)
-    }
-}
-
-impl std::error::Error for SolverProblemsException {}
+// `learned_pool` holds `Rc<RefCell<Rule>>`, so this exception rides an inner `Result` rather than
+// an `anyhow::Error`.
+shirabe_php_shim::impl_php_exception!(
+    SolverProblemsException,
+    inner,
+    r"Composer\DependencyResolver\SolverProblemsException",
+    !Send
+);