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>

5 files changed, 55 insertions, 93 deletions

diff --git a/crates/shirabe/src/package/loader/array_loader.rs b/crates/shirabe/src/package/loader/array_loader.rs
index 0940183c..2c6d3971 100644
--- a/crates/shirabe/src/package/loader/array_loader.rs
+++ b/crates/shirabe/src/package/loader/array_loader.rs
@@ -69,23 +69,17 @@ impl ArrayLoader {
         class: &str,
     ) -> anyhow::Result<CompleteOrRootPackage> {
         if !config.contains_key("name") {
-            return Err(UnexpectedValueException {
-                message: format!(
-                    "Unknown package has no name defined ({}).",
-                    json_encode(&PhpMixed::Array(config.clone())).unwrap_or_default()
-                ),
-                code: 0,
-            }
+            return Err(UnexpectedValueException::new(format!(
+                "Unknown package has no name defined ({}).",
+                json_encode(&PhpMixed::Array(config.clone())).unwrap_or_default()
+            ))
             .into());
         }
         if !config.contains_key("version") || !is_scalar(config.get("version").unwrap()) {
-            return Err(UnexpectedValueException {
-                message: format!(
-                    "Package {} has no version defined.",
-                    config.get("name").and_then(|v| v.as_string()).unwrap_or("")
-                ),
-                code: 0,
-            }
+            return Err(UnexpectedValueException::new(format!(
+                "Package {} has no version defined.",
+                config.get("name").and_then(|v| v.as_string()).unwrap_or("")
+            ))
             .into());
         }
         let mut config_version = config.get("version").cloned().unwrap_or(PhpMixed::Null);
@@ -118,14 +112,11 @@ impl ArrayLoader {
             {
                 Ok(v) => version = v,
                 Err(e) => {
-                    return Err(UnexpectedValueException {
-                        message: format!(
-                            "Failed to normalize version for package \"{}\": {}",
-                            config.get("name").and_then(|v| v.as_string()).unwrap_or(""),
-                            e
-                        ),
-                        code: 0,
-                    }
+                    return Err(UnexpectedValueException::new(format!(
+                        "Failed to normalize version for package \"{}\": {}",
+                        config.get("name").and_then(|v| v.as_string()).unwrap_or(""),
+                        e
+                    ))
                     .into());
                 }
             }
@@ -226,18 +217,14 @@ impl ArrayLoader {
                 })
                 .unwrap_or(false);
             if !has_required {
-                return Err(UnexpectedValueException {
-                    message: format!(
-                        "Package {}'s source key should be specified as {{\"type\": ..., \"url\": ..., \"reference\": ...}},\n{} given.",
-
-                            config
-                                .get("name")
-                                .and_then(|v| v.as_string())
-                                .unwrap_or(""),
-                        json_encode(&source).unwrap_or_default(),
-                    ),
-                    code: 0,
-                }
+                return Err(UnexpectedValueException::new(format!(
+                    "Package {}'s source key should be specified as {{\"type\": ..., \"url\": ..., \"reference\": ...}},\n{} given.",
+                    config
+                        .get("name")
+                        .and_then(|v| v.as_string())
+                        .unwrap_or(""),
+                    json_encode(&source).unwrap_or_default(),
+                ))
                 .into());
             }
             let source_map = source_map.unwrap();
@@ -270,18 +257,14 @@ impl ArrayLoader {
                 .map(|m| m.contains_key("type") && m.contains_key("url"))
                 .unwrap_or(false);
             if !has_required {
-                return Err(UnexpectedValueException {
-                    message: format!(
-                        "Package {}'s dist key should be specified as {{\"type\": ..., \"url\": ..., \"reference\": ..., \"shasum\": ...}},\n{} given.",
-
-                            config
-                                .get("name")
-                                .and_then(|v| v.as_string())
-                                .unwrap_or(""),
-                        json_encode(&dist).unwrap_or_default(),
-                    ),
-                    code: 0,
-                }
+                return Err(UnexpectedValueException::new(format!(
+                    "Package {}'s dist key should be specified as {{\"type\": ..., \"url\": ..., \"reference\": ..., \"shasum\": ...}},\n{} given.",
+                    config
+                        .get("name")
+                        .and_then(|v| v.as_string())
+                        .unwrap_or(""),
+                    json_encode(&dist).unwrap_or_default(),
+                ))
                 .into());
             }
             let dist_map = dist_map.unwrap();
@@ -672,13 +655,10 @@ impl ArrayLoader {
         let parsed_constraint = match self.version_parser.parse_constraints(&constraint) {
             Ok(c) => c,
             Err(_e) => {
-                return Err(UnexpectedValueException {
-                    message: format!(
-                        "Link constraint in {} {} > {} should be a valid version constraint, got \"{}\"",
-                        source, description, target, constraint
-                    ),
-                    code: 0,
-                }
+                return Err(UnexpectedValueException::new(format!(
+                    "Link constraint in {} {} > {} should be a valid version constraint, got \"{}\"",
+                    source, description, target, constraint
+                ))
                 .into());
             }
         };
@@ -702,11 +682,9 @@ impl ArrayLoader {
         config: &IndexMap<String, PhpMixed>,
     ) -> anyhow::Result<Option<String>> {
         if !config.contains_key("version") || !is_scalar(config.get("version").unwrap()) {
-            return Err(UnexpectedValueException {
-                message: "no/invalid version defined".to_string(),
-                code: 0,
-            }
-            .into());
+            return Err(
+                UnexpectedValueException::new("no/invalid version defined".to_string()).into(),
+            );
         }
         let mut config_version = config.get("version").cloned().unwrap_or(PhpMixed::Null);
         if !is_string(&config_version) {
diff --git a/crates/shirabe/src/package/loader/invalid_package_exception.rs b/crates/shirabe/src/package/loader/invalid_package_exception.rs
index 2bd22c61..23251994 100644
--- a/crates/shirabe/src/package/loader/invalid_package_exception.rs
+++ b/crates/shirabe/src/package/loader/invalid_package_exception.rs
@@ -27,7 +27,7 @@ impl InvalidPackageException {
                 .join("\n")
         );
         Self {
-            inner: Exception { message, code: 0 },
+            inner: Exception::new(message),
             errors,
             warnings,
             data,
@@ -47,10 +47,8 @@ impl InvalidPackageException {
     }
 }
 
-impl std::fmt::Display for InvalidPackageException {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.inner.message)
-    }
-}
-
-impl std::error::Error for InvalidPackageException {}
+shirabe_php_shim::impl_php_exception!(
+    InvalidPackageException,
+    inner,
+    r"Composer\Package\Loader\InvalidPackageException"
+);
diff --git a/crates/shirabe/src/package/loader/json_loader.rs b/crates/shirabe/src/package/loader/json_loader.rs
index c30fbe07..d9e7100a 100644
--- a/crates/shirabe/src/package/loader/json_loader.rs
+++ b/crates/shirabe/src/package/loader/json_loader.rs
@@ -34,10 +34,7 @@ impl JsonLoader {
         let config: IndexMap<String, PhpMixed> = match config {
             PhpMixed::Array(m) => m,
             _ => {
-                return Err(TypeError {
-                    message: "Composer\\Package\\Loader\\LoaderInterface::load(): Argument #1 ($config) must be of type array".to_string(),
-                    code: 0,
-                }
+                return Err(TypeError::new("Composer\\Package\\Loader\\LoaderInterface::load(): Argument #1 ($config) must be of type array".to_string())
                 .into());
             }
         };
diff --git a/crates/shirabe/src/package/loader/root_package_loader.rs b/crates/shirabe/src/package/loader/root_package_loader.rs
index 284bb175..e26a7e95 100644
--- a/crates/shirabe/src/package/loader/root_package_loader.rs
+++ b/crates/shirabe/src/package/loader/root_package_loader.rs
@@ -78,10 +78,7 @@ impl RootPackageLoader {
             config["name"].as_string().unwrap_or(""),
             false,
         ) {
-            return Err(anyhow::anyhow!(RuntimeException {
-                message: format!("Your package name {}", err),
-                code: 0,
-            }));
+            return Err(RuntimeException::new(format!("Your package name {}", err)).into());
         }
 
         let mut auto_versioned = false;
@@ -197,13 +194,10 @@ impl RootPackageLoader {
 
                 let package_name = config["name"].as_string().unwrap_or("").to_string();
                 if links.contains_key(&package_name) {
-                    return Err(anyhow::anyhow!(RuntimeException {
-                        message: format!(
-                            "Root package '{}' cannot require itself in its composer.json\nDid you accidentally name your root package after an external package?",
-                            package_name
-                        ),
-                        code: 0,
-                    }));
+                    return Err(RuntimeException::new(format!(
+                        "Root package '{}' cannot require itself in its composer.json\nDid you accidentally name your root package after an external package?",
+                        package_name
+                    )).into());
                 }
             }
         }
@@ -216,10 +210,7 @@ impl RootPackageLoader {
                     if let Some(err) =
                         ValidatingArrayLoader::has_package_naming_error(link_name, true)
                     {
-                        return Err(anyhow::anyhow!(RuntimeException {
-                            message: format!("{}.{}", link_type, err),
-                            code: 0,
-                        }));
+                        return Err(RuntimeException::new(format!("{}.{}", link_type, err)).into());
                     }
                 }
             }
@@ -291,14 +282,11 @@ impl RootPackageLoader {
                 return {
                     panic!(
                         "{}",
-                        UnexpectedValueException {
-                            message: format!(
+                        UnexpectedValueException::new(format!(
                                 "Invalid alias definition in \"{}\": \"{}\". Aliases should be in the form \"exact-version as other-exact-version\".",
                                 req_name, req_version
-                            ),
-                            code: 0,
-                        }
-                        .message
+                            ))
+                        .get_message()
                     )
                 };
             }
diff --git a/crates/shirabe/src/package/loader/validating_array_loader.rs b/crates/shirabe/src/package/loader/validating_array_loader.rs
index a050f2d7..fc8eed00 100644
--- a/crates/shirabe/src/package/loader/validating_array_loader.rs
+++ b/crates/shirabe/src/package/loader/validating_array_loader.rs
@@ -1583,11 +1583,12 @@ impl LoaderInterface for ValidatingArrayLoader {
         }
 
         if !self.errors.borrow().is_empty() {
-            return Err(anyhow::anyhow!(InvalidPackageException::new(
+            return Err(InvalidPackageException::new(
                 self.errors.borrow().clone(),
                 self.warnings.borrow().clone(),
                 config.iter().map(|(k, v)| (k.clone(), v.clone())).collect(),
-            )));
+            )
+            .into());
         }
 
         let package = self.loader.load(