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, 7 insertions, 10 deletions

diff --git a/crates/shirabe/src/command/script_alias_command.rs b/crates/shirabe/src/command/script_alias_command.rs
index e6a13545..e3faf3a6 100644
--- a/crates/shirabe/src/command/script_alias_command.rs
+++ b/crates/shirabe/src/command/script_alias_command.rs
@@ -36,12 +36,10 @@ impl ScriptAliasCommand {
 
         for alias in &aliases {
             if !is_string(&PhpMixed::String(alias.clone())) {
-                return Err(InvalidArgumentException {
-                    message:
-                        r#""scripts-aliases" element array values should contain only strings"#
-                            .to_string(),
-                    code: 0,
-                }
+                return Err(InvalidArgumentException::new(
+                    r#""scripts-aliases" element array values should contain only strings"#
+                        .to_string(),
+                )
                 .into());
             }
         }
@@ -123,10 +121,9 @@ impl Command for ScriptAliasCommand {
         // TODO(phase-c): InputInterface has_to_string/get_class_name not modeled in Rust
         // TODO remove for Symfony 6+ as it is then in the interface
         if false {
-            return Err(LogicException {
-                message: "Expected an Input instance that is stringable".to_string(),
-                code: 0,
-            }
+            return Err(LogicException::new(
+                "Expected an Input instance that is stringable".to_string(),
+            )
             .into());
         }