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>

3 files changed, 49 insertions, 75 deletions

diff --git a/crates/shirabe/src/json/json_file.rs b/crates/shirabe/src/json/json_file.rs
index 1d6a75ce..2d061ced 100644
--- a/crates/shirabe/src/json/json_file.rs
+++ b/crates/shirabe/src/json/json_file.rs
@@ -11,6 +11,7 @@ use crate::util::Silencer;
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
 use shirabe_external_packages::seld::json_lint::{ParsingException, ParsingExceptionDetails};
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     InvalidArgumentException, JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_UNESCAPED_UNICODE,
     PhpMixed, RuntimeException, UnexpectedValueException, dirname, file_exists, file_get_contents,
@@ -108,10 +109,9 @@ impl JsonFile {
         io: Option<std::rc::Rc<std::cell::RefCell<dyn IOInterface>>>,
     ) -> anyhow::Result<Self> {
         if http_downloader.is_none() && Preg::is_match(php_regex!(r"{^https?://}i"), &path) {
-            return Err(InvalidArgumentException {
-                message: "http urls require a HttpDownloader instance to be passed".to_string(),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(
+                "http urls require a HttpDownloader instance to be passed".to_string(),
+            )
             .into());
         }
         Ok(Self {
@@ -145,10 +145,10 @@ impl JsonFile {
                     .map(|s| s.to_string()))
             } else {
                 if !Filesystem::is_readable(&self.path) {
-                    return Err(RuntimeException {
-                        message: format!("The file \"{}\" is not readable.", self.path),
-                        code: 0,
-                    }
+                    return Err(RuntimeException::new(format!(
+                        "The file \"{}\" is not readable.",
+                        self.path
+                    ))
                     .into());
                 }
                 if let Some(io) = &self.io
@@ -173,17 +173,13 @@ impl JsonFile {
             Err(e) => {
                 // TransportException keeps its message verbatim; any other exception is wrapped
                 // with the "Could not read" prefix.
-                if let Some(te) = e.downcast_ref::<TransportException>() {
-                    return Err(RuntimeException {
-                        message: te.message.clone(),
-                        code: 0,
-                    }
-                    .into());
-                }
-                return Err(RuntimeException {
-                    message: format!("Could not read {}\n\n{}", self.path, e),
-                    code: 0,
+                if let Some(te) = e.catch::<TransportException>() {
+                    return Err(RuntimeException::new(te.get_message().to_string()).into());
                 }
+                return Err(RuntimeException::new(format!(
+                    "Could not read {}\n\n{}",
+                    self.path, e
+                ))
                 .into());
             }
         };
@@ -191,11 +187,7 @@ impl JsonFile {
         let json = match json {
             Some(j) => j,
             None => {
-                return Err(RuntimeException {
-                    message: format!("Could not read {}", self.path),
-                    code: 0,
-                }
-                .into());
+                return Err(RuntimeException::new(format!("Could not read {}", self.path)).into());
             }
         };
 
@@ -230,21 +222,18 @@ impl JsonFile {
         let dir = dirname(&self.path);
         if !is_dir(&dir) {
             if file_exists(&dir) {
-                return Err(UnexpectedValueException {
-                    message: format!(
-                        "{} exists and is not a directory.",
-                        realpath(&dir).unwrap_or_default(),
-                    ),
-                    code: 0,
-                }
+                return Err(UnexpectedValueException::new(format!(
+                    "{} exists and is not a directory.",
+                    realpath(&dir).unwrap_or_default(),
+                ))
                 .into());
             }
             // PHP: @mkdir($dir, 0777, true)
             if !Silencer::call(|| Ok(mkdir(&dir, 0o777, true))).unwrap_or(false) {
-                return Err(UnexpectedValueException {
-                    message: format!("{} does not exist and could not be created.", dir),
-                    code: 0,
-                }
+                return Err(UnexpectedValueException::new(format!(
+                    "{} does not exist and could not be created.",
+                    dir
+                ))
                 .into());
             }
         }
@@ -305,10 +294,10 @@ impl JsonFile {
     /// @return true                    true on success
     pub fn validate_schema(&self, schema: i64, schema_file: Option<&str>) -> anyhow::Result<bool> {
         if !Filesystem::is_readable(&self.path) {
-            return Err(RuntimeException {
-                message: format!("The file \"{}\" is not readable.", self.path),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "The file \"{}\" is not readable.",
+                self.path
+            ))
             .into());
         }
         let content = file_get_contents(&self.path).unwrap_or_default();
@@ -446,10 +435,8 @@ impl JsonFile {
         data: &T,
         options: JsonEncodeOptions,
     ) -> anyhow::Result<String> {
-        let json = json_encode_ex(data, options.to_flags()).map_err(|err| RuntimeException {
-            message: format!("JSON encoding failed: {}", err),
-            code: 0,
-        })?;
+        let json = json_encode_ex(data, options.to_flags())
+            .map_err(|err| RuntimeException::new(format!("JSON encoding failed: {}", err)))?;
 
         if options.pretty_print && options.indent != Self::INDENT_DEFAULT {
             // Pretty printing and not using default indentation
diff --git a/crates/shirabe/src/json/json_manipulator.rs b/crates/shirabe/src/json/json_manipulator.rs
index eec823b6..d66fe645 100644
--- a/crates/shirabe/src/json/json_manipulator.rs
+++ b/crates/shirabe/src/json/json_manipulator.rs
@@ -36,10 +36,9 @@ impl JsonManipulator {
             contents = "{}".to_string();
         }
         if !Preg::is_match3(php_regex!("#^\\{(.*)\\}$#s"), &contents, None) {
-            return Err(InvalidArgumentException {
-                message: "The json file must be an object ({})".to_string(),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(
+                "The json file must be an object ({})".to_string(),
+            )
             .into());
         }
         let newline = if strpos(&contents, "\r\n").is_some() {
@@ -823,10 +822,10 @@ impl JsonManipulator {
                     );
                 }
             } else {
-                return Err(LogicException {
-                    message: format!("Nothing matched above for: {}", children),
-                    code: 0,
-                }
+                return Err(LogicException::new(format!(
+                    "Nothing matched above for: {}",
+                    children
+                ))
                 .into());
             }
         }
@@ -940,10 +939,7 @@ impl JsonManipulator {
             children_clean = Some(children.clone());
         }
 
-        let children_clean = children_clean.ok_or_else(|| InvalidArgumentException {
-            message: "JsonManipulator: $childrenClean is not defined. Please report at https://github.com/composer/composer/issues/new.".to_string(),
-            code: 0,
-        })?;
+        let children_clean = children_clean.ok_or_else(|| InvalidArgumentException::new("JsonManipulator: $childrenClean is not defined. Please report at https://github.com/composer/composer/issues/new.".to_string()))?;
 
         // no child data left, $name was the only key in
         let mut empty_match: IndexMap<String, String> = IndexMap::new();
@@ -1113,11 +1109,9 @@ impl JsonManipulator {
                 );
             }
         } else {
-            return Err(LogicException {
-                message: format!("Nothing matched above for: {}", children),
-                code: 0,
-            }
-            .into());
+            return Err(
+                LogicException::new(format!("Nothing matched above for: {}", children)).into(),
+            );
         }
 
         self.contents = format!("{}{}{}", node_start, children, node_end);
@@ -1132,10 +1126,9 @@ impl JsonManipulator {
         index: i64,
     ) -> anyhow::Result<bool> {
         if index < 0 {
-            return Err(InvalidArgumentException {
-                message: "Index can only be positive integer".to_string(),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(
+                "Index can only be positive integer".to_string(),
+            )
             .into());
         }
 
diff --git a/crates/shirabe/src/json/json_validation_exception.rs b/crates/shirabe/src/json/json_validation_exception.rs
index a63edda3..cb7370d2 100644
--- a/crates/shirabe/src/json/json_validation_exception.rs
+++ b/crates/shirabe/src/json/json_validation_exception.rs
@@ -11,7 +11,7 @@ pub struct JsonValidationException {
 impl JsonValidationException {
     pub fn new(message: String, errors: Vec<String>) -> Self {
         Self {
-            inner: Exception { message, code: 0 },
+            inner: Exception::new(message),
             errors,
         }
     }
@@ -19,16 +19,10 @@ impl JsonValidationException {
     pub fn get_errors(&self) -> &Vec<String> {
         &self.errors
     }
-
-    pub fn get_message(&self) -> &str {
-        &self.inner.message
-    }
-}
-
-impl std::fmt::Display for JsonValidationException {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.inner.message)
-    }
 }
 
-impl std::error::Error for JsonValidationException {}
+shirabe_php_shim::impl_php_exception!(
+    JsonValidationException,
+    inner,
+    r"Composer\Json\JsonValidationException"
+);