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>

15 files changed, 334 insertions, 496 deletions

diff --git a/crates/shirabe/src/downloader/archive_downloader.rs b/crates/shirabe/src/downloader/archive_downloader.rs
index 6ddf29b6..d2ee4a75 100644
--- a/crates/shirabe/src/downloader/archive_downloader.rs
+++ b/crates/shirabe/src/downloader/archive_downloader.rs
@@ -9,6 +9,7 @@ use crate::util::Filesystem;
 use crate::util::Platform;
 use indexmap::IndexMap;
 use shirabe_external_packages::symfony::finder::Finder;
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     DIRECTORY_SEPARATOR, PhpMixed, RuntimeException, bin2hex, file_exists, is_dir, random_bytes,
     realpath,
@@ -155,7 +156,7 @@ pub trait ArchiveDownloader {
                         Ok(false) => {}
                         Err(e) => {
                             // ignore error, and simply do not renameAsOne
-                            if e.downcast_ref::<RuntimeException>().is_none() {
+                            if !e.is_instanceof::<RuntimeException>() {
                                 return Err(e);
                             }
                         }
@@ -273,14 +274,11 @@ fn rename_recursively(
         );
         if is_dir(&target) {
             if !is_dir(file) {
-                return Err(RuntimeException {
-                    message: format!(
-                        "Installing {} would lead to overwriting the {} directory with a file from the package, invalid operation.",
-                        package,
-                        target.display()
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Installing {} would lead to overwriting the {} directory with a file from the package, invalid operation.",
+                    package,
+                    target.display()
+                ))
                 .into());
             }
             rename_recursively(filesystem, package.clone(), file, &target)?;
diff --git a/crates/shirabe/src/downloader/download_manager.rs b/crates/shirabe/src/downloader/download_manager.rs
index 423eda28..8c10de5d 100644
--- a/crates/shirabe/src/downloader/download_manager.rs
+++ b/crates/shirabe/src/downloader/download_manager.rs
@@ -9,6 +9,7 @@ use crate::package::PackageInterfaceHandle;
 use crate::util::Filesystem;
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::Preg;
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     InvalidArgumentException, LogicException, PhpMixed, RuntimeException, array_keys,
     array_reverse, array_shift, dirname, implode, in_array_strict, preg_quote, rtrim, str_replace,
@@ -99,14 +100,11 @@ impl DownloadManager {
     ) -> anyhow::Result<std::rc::Rc<std::cell::RefCell<dyn DownloaderInterface>>> {
         let r#type = strtolower(r#type);
         if !self.downloaders.contains_key(&r#type) {
-            return Err(InvalidArgumentException {
-                message: format!(
-                    "Unknown downloader type: {}. Available types: {}.",
-                    r#type,
-                    implode(", ", &array_keys(&self.downloaders)),
-                ),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "Unknown downloader type: {}. Available types: {}.",
+                r#type,
+                implode(", ", &array_keys(&self.downloaders)),
+            ))
             .into());
         }
 
@@ -134,28 +132,22 @@ impl DownloadManager {
         } else if installation_source.as_deref() == Some("source") {
             self.get_downloader(&package.get_source_type().unwrap_or_default())?
         } else {
-            return Err(InvalidArgumentException {
-                message: format!(
-                    "Package {} does not have an installation source set",
-                    package,
-                ),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "Package {} does not have an installation source set",
+                package,
+            ))
             .into());
         };
 
         let downloader_installation_source = downloader.borrow().get_installation_source();
         if installation_source.as_deref() != Some(&downloader_installation_source) {
-            return Err(LogicException {
-                message: format!(
-                    "Downloader \"{}\" is a {} type downloader and can not be used to download {} for package {}",
-                    downloader.borrow().php_class_name(),
-                    downloader_installation_source,
-                    installation_source.unwrap_or_default(),
-                    package,
-                ),
-                code: 0,
-            }
+            return Err(LogicException::new(format!(
+                "Downloader \"{}\" is a {} type downloader and can not be used to download {} for package {}",
+                downloader.borrow().php_class_name(),
+                downloader_installation_source,
+                installation_source.unwrap_or_default(),
+                package,
+            ))
             .into());
         }
 
@@ -227,19 +219,18 @@ impl DownloadManager {
             {
                 Ok(r) => r,
                 Err(e) => {
-                    let is_runtime = e.downcast_ref::<RuntimeException>().is_some();
-                    let is_irrecoverable =
-                        e.downcast_ref::<IrrecoverableDownloadException>().is_some();
-                    if is_runtime && !is_irrecoverable {
+                    if e.is_instanceof::<RuntimeException>()
+                        && !e.is_instanceof::<IrrecoverableDownloadException>()
+                    {
                         if sources.is_empty() {
                             return Err(e);
                         }
 
                         let message = e
-                            .downcast_ref::<RuntimeException>()
+                            .catch::<RuntimeException>()
                             .unwrap()
-                            .message
-                            .clone();
+                            .get_message()
+                            .to_string();
                         self.io.write_error3(
                             &format!(
                                 "    <warning>Failed to download {} from {}: {}</warning>",
@@ -352,17 +343,17 @@ impl DownloadManager {
                 Ok(p) => return Ok(p),
                 Err(e) => {
                     // PHP catches only \RuntimeException; other exceptions propagate uncaught.
-                    if e.downcast_ref::<RuntimeException>().is_none() {
+                    if !e.is_instanceof::<RuntimeException>() {
                         return Err(e);
                     }
                     if !self.io.is_interactive() {
                         return Err(e);
                     }
                     let message = e
-                        .downcast_ref::<RuntimeException>()
+                        .catch::<RuntimeException>()
                         .unwrap()
-                        .message
-                        .clone();
+                        .get_message()
+                        .to_string();
                     self.io.write_error3(
                         &format!("<error>    Update failed ({})</error>", message),
                         true,
@@ -477,10 +468,10 @@ impl DownloadManager {
         }
 
         if sources.is_empty() {
-            return Err(InvalidArgumentException {
-                message: format!("Package {} must have a source or dist specified", package),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "Package {} must have a source or dist specified",
+                package
+            ))
             .into());
         }
 
diff --git a/crates/shirabe/src/downloader/file_downloader.rs b/crates/shirabe/src/downloader/file_downloader.rs
index cdcf750e..9b86ee56 100644
--- a/crates/shirabe/src/downloader/file_downloader.rs
+++ b/crates/shirabe/src/downloader/file_downloader.rs
@@ -25,6 +25,7 @@ use crate::util::Silencer;
 use crate::util::Url as UrlUtil;
 use crate::util::sync_executor;
 use indexmap::IndexMap;
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     DIRECTORY_SEPARATOR, InvalidArgumentException, PATHINFO_BASENAME, PATHINFO_EXTENSION,
     PHP_URL_PATH, PhpMixed, RuntimeException, UnexpectedValueException, array_search, file_exists,
@@ -359,11 +360,9 @@ impl FileDownloader {
         url: &str,
     ) -> anyhow::Result<String> {
         if !shirabe_php_shim::extension_loaded("openssl") && Some(0) == strpos(url, "https:") {
-            return Err(RuntimeException {
-                message: "You must enable the openssl extension to download files via https"
-                    .to_string(),
-                code: 0,
-            }
+            return Err(RuntimeException::new(
+                "You must enable the openssl extension to download files via https".to_string(),
+            )
             .into());
         }
 
@@ -400,10 +399,9 @@ impl DownloaderInterface for FileDownloader {
         output: bool,
     ) -> anyhow::Result<Option<PhpMixed>> {
         if package.get_dist_url().is_none() {
-            return Err(InvalidArgumentException {
-                message: "The given package is missing url information".to_string(),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(
+                "The given package is missing url information".to_string(),
+            )
             .into());
         }
 
@@ -558,15 +556,15 @@ impl DownloaderInterface for FileDownloader {
                         }
                         self.clear_last_cache_write(package.clone());
 
-                        if e.downcast_ref::<IrrecoverableDownloadException>().is_some() {
+                        if e.is_instanceof::<IrrecoverableDownloadException>() {
                             return Err(e);
                         }
 
-                        if e.downcast_ref::<MaxFileSizeExceededException>().is_some() {
+                        if e.is_instanceof::<MaxFileSizeExceededException>() {
                             return Err(e);
                         }
 
-                        if let Some(te) = e.downcast_ref::<TransportException>() {
+                        if let Some(te) = e.catch::<TransportException>() {
                             // if we got an http response with a proper code, then requesting again will probably not help, abort
                             if 0 != te.get_code() && !matches!(te.get_code(), 500 | 502 | 503 | 504)
                             {
@@ -592,7 +590,7 @@ impl DownloaderInterface for FileDownloader {
                         }
                         if !urls.is_empty() {
                             let code = e
-                                .downcast_ref::<TransportException>()
+                                .catch::<TransportException>()
                                 .map_or(0, |te| te.get_code());
                             if self.io.borrow().is_debug() {
                                 self.io.borrow().write_error(&format!(
@@ -628,13 +626,10 @@ impl DownloaderInterface for FileDownloader {
 
             // === $result->then(verify) ===
             if !file_exists(&file_name) {
-                return Err(UnexpectedValueException {
-                    message: format!(
-                        "{} could not be saved to {}, make sure the directory is writable and you have internet connectivity",
-                        url.base, file_name
-                    ),
-                    code: 0,
-                }
+                return Err(UnexpectedValueException::new(format!(
+                    "{} could not be saved to {}, make sure the directory is writable and you have internet connectivity",
+                    url.base, file_name
+                ))
                 .into());
             }
 
@@ -642,13 +637,10 @@ impl DownloaderInterface for FileDownloader {
                 && !checksum.is_empty()
                 && hash_file("sha1", &file_name).as_deref() != Some(checksum)
             {
-                return Err(UnexpectedValueException {
-                    message: format!(
-                        "The checksum verification of the file failed (downloaded from {})",
-                        url.base
-                    ),
-                    code: 0,
-                }
+                return Err(UnexpectedValueException::new(format!(
+                    "The checksum verification of the file failed (downloaded from {})",
+                    url.base
+                ))
                 .into());
             }
 
@@ -809,10 +801,10 @@ impl DownloaderInterface for FileDownloader {
         }
         let result = Filesystem::remove_directory_async_via(&self.filesystem, path).await?;
         if !result {
-            return Err(RuntimeException {
-                message: format!("Could not completely delete {}, aborting.", path),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Could not completely delete {}, aborting.",
+                path
+            ))
             .into());
         }
 
diff --git a/crates/shirabe/src/downloader/filesystem_exception.rs b/crates/shirabe/src/downloader/filesystem_exception.rs
index f0aa831f..6e90e328 100644
--- a/crates/shirabe/src/downloader/filesystem_exception.rs
+++ b/crates/shirabe/src/downloader/filesystem_exception.rs
@@ -7,17 +7,15 @@ pub struct FilesystemException(pub Exception);
 
 impl FilesystemException {
     pub fn new(message: String, code: i64) -> Self {
-        FilesystemException(Exception {
-            message: format!("Filesystem exception: \n{}", message),
+        FilesystemException(Exception::with_code(
+            format!("Filesystem exception: \n{}", message),
             code,
-        })
+        ))
     }
 }
 
-impl std::fmt::Display for FilesystemException {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        self.0.fmt(f)
-    }
-}
-
-impl std::error::Error for FilesystemException {}
+shirabe_php_shim::impl_php_exception!(
+    FilesystemException,
+    0,
+    r"Composer\Downloader\FilesystemException"
+);
diff --git a/crates/shirabe/src/downloader/fossil_downloader.rs b/crates/shirabe/src/downloader/fossil_downloader.rs
index 72409a1f..86a44f0b 100644
--- a/crates/shirabe/src/downloader/fossil_downloader.rs
+++ b/crates/shirabe/src/downloader/fossil_downloader.rs
@@ -47,14 +47,11 @@ impl FossilDownloader {
             .execute(&command, output, cwd.as_deref())?
             != 0
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "Failed to execute {}\n\n{}",
-                    command.join(" "),
-                    self.inner.process.borrow().get_error_output()
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Failed to execute {}\n\n{}",
+                command.join(" "),
+                self.inner.process.borrow().get_error_output()
+            ))
             .into());
         }
         Ok(())
@@ -168,13 +165,10 @@ impl VcsDownloader for FossilDownloader {
         ));
 
         if !self.has_metadata_repository(path) {
-            return Err(RuntimeException {
-                message: format!(
-                    "The .fslckout file is missing from {}, see https://getcomposer.org/commit-deps for more information",
-                    path
-                ),
-                code: 0,
-            }.into());
+            return Err(RuntimeException::new(format!(
+                "The .fslckout file is missing from {}, see https://getcomposer.org/commit-deps for more information",
+                path
+            )).into());
         }
 
         let real_path = shirabe_php_shim::realpath(path);
diff --git a/crates/shirabe/src/downloader/git_downloader.rs b/crates/shirabe/src/downloader/git_downloader.rs
index 275050fd..0a32d2fd 100644
--- a/crates/shirabe/src/downloader/git_downloader.rs
+++ b/crates/shirabe/src/downloader/git_downloader.rs
@@ -86,14 +86,11 @@ impl GitDownloader {
             .execute_args(&command, &mut output, Some(&path))
             != 0
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "Failed to execute {}\n\n{}",
-                    implode(" ", &command),
-                    self.inner.process.borrow().get_error_output(),
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Failed to execute {}\n\n{}",
+                implode(" ", &command),
+                self.inner.process.borrow().get_error_output(),
+            ))
             .into());
         }
 
@@ -186,14 +183,11 @@ impl GitDownloader {
                         Some(&path),
                     ) != 0
                     {
-                        return Err(RuntimeException {
-                            message: format!(
-                                "Failed to execute {}\n\n{}",
-                                implode(" ", &command),
-                                self.inner.process.borrow().get_error_output(),
-                            ),
-                            code: 0,
-                        }
+                        return Err(RuntimeException::new(format!(
+                            "Failed to execute {}\n\n{}",
+                            implode(" ", &command),
+                            self.inner.process.borrow().get_error_output(),
+                        ))
                         .into());
                     }
 
@@ -232,14 +226,11 @@ impl GitDownloader {
                     .execute_args(&command, &mut output, Some(&path))
                     != 0
                 {
-                    return Err(RuntimeException {
-                        message: format!(
-                            "Failed to execute {}\n\n{}",
-                            implode(" ", &command),
-                            self.inner.process.borrow().get_error_output(),
-                        ),
-                        code: 0,
-                    }
+                    return Err(RuntimeException::new(format!(
+                        "Failed to execute {}\n\n{}",
+                        implode(" ", &command),
+                        self.inner.process.borrow().get_error_output(),
+                    ))
                     .into());
                 }
                 refs = trim(&output, None);
@@ -486,15 +477,12 @@ impl GitDownloader {
 
         let command = format!("{} && {}", implode(" ", &command1), implode(" ", &command2));
 
-        Err(RuntimeException {
-            message: Url::sanitize(format!(
-                "Failed to execute {}\n\n{}{}",
-                command,
-                self.inner.process.borrow().get_error_output(),
-                exception_extra,
-            )),
-            code: 0,
-        }
+        Err(RuntimeException::new(Url::sanitize(format!(
+            "Failed to execute {}\n\n{}{}",
+            command,
+            self.inner.process.borrow().get_error_output(),
+            exception_extra,
+        )))
         .into())
     }
 
@@ -570,11 +558,9 @@ impl GitDownloader {
             Some(&path),
         ) != 0
         {
-            return Err(RuntimeException {
-                message: format!("Could not reset changes\n\n:{}", output),
-                code: 0,
-            }
-            .into());
+            return Err(
+                RuntimeException::new(format!("Could not reset changes\n\n:{}", output)).into(),
+            );
         }
         let mut output = String::new();
         if self.inner.process.borrow_mut().execute_args(
@@ -583,11 +569,9 @@ impl GitDownloader {
             Some(&path),
         ) != 0
         {
-            return Err(RuntimeException {
-                message: format!("Could not reset changes\n\n:{}", output),
-                code: 0,
-            }
-            .into());
+            return Err(
+                RuntimeException::new(format!("Could not reset changes\n\n:{}", output)).into(),
+            );
         }
 
         self.has_discarded_changes.borrow_mut().insert(path, true);
@@ -609,11 +593,9 @@ impl GitDownloader {
             Some(&path),
         ) != 0
         {
-            return Err(RuntimeException {
-                message: format!("Could not stash changes\n\n:{}", output),
-                code: 0,
-            }
-            .into());
+            return Err(
+                RuntimeException::new(format!("Could not stash changes\n\n:{}", output)).into(),
+            );
         }
 
         self.has_stashed_changes.borrow_mut().insert(path, true);
@@ -631,11 +613,9 @@ impl GitDownloader {
             Some(&path),
         ) != 0
         {
-            return Err(RuntimeException {
-                message: format!("Could not view diff\n\n:{}", output),
-                code: 0,
-            }
-            .into());
+            return Err(
+                RuntimeException::new(format!("Could not view diff\n\n:{}", output)).into(),
+            );
         }
 
         self.inner
@@ -692,10 +672,10 @@ impl GitDownloader {
         path: &str,
     ) -> anyhow::Result<()> {
         if self.get_local_changes(package, path)?.is_some() {
-            return Err(RuntimeException {
-                message: format!("Source directory {} has uncommitted changes.", path),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Source directory {} has uncommitted changes.",
+                path
+            ))
             .into());
         }
 
@@ -738,14 +718,11 @@ impl ChangeReportInterface for GitDownloader {
             .execute_args(&command, &mut output, Some(path))
             != 0
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "Failed to execute {}\n\n{}",
-                    implode(" ", &command),
-                    self.inner.process.borrow().get_error_output(),
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Failed to execute {}\n\n{}",
+                implode(" ", &command),
+                self.inner.process.borrow().get_error_output(),
+            ))
             .into());
         }
 
@@ -848,10 +825,9 @@ impl VcsDownloader for GitDownloader {
                     .insert(r#ref.as_deref().unwrap_or("").to_string(), true);
             }
         } else if git_version.is_none() {
-            return Err(RuntimeException {
-                message: "git was not found in your PATH, skipping source download".to_string(),
-                code: 0,
-            }
+            return Err(RuntimeException::new(
+                "git was not found in your PATH, skipping source download".to_string(),
+            )
             .into());
         }
 
@@ -975,13 +951,10 @@ impl VcsDownloader for GitDownloader {
                 ],
             ];
             if Platform::get_env("COMPOSER_DISABLE_NETWORK").is_some() {
-                return Err(RuntimeException {
-                    message: format!(
-                        "The required git reference for {} is not in cache and network is disabled, aborting",
-                        package.get_name(),
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "The required git reference for {} is not in cache and network is disabled, aborting",
+                    package.get_name(),
+                ))
                 .into());
             }
         }
@@ -1022,13 +995,10 @@ impl VcsDownloader for GitDownloader {
         GitUtil::clean_env(&self.inner.process);
         let path = self.normalize_path(path);
         if !self.has_metadata_repository(&path) {
-            return Err(RuntimeException {
-                message: format!(
-                    "The .git directory is missing from {}, see https://getcomposer.org/commit-deps for more information",
-                    path
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "The .git directory is missing from {}, see https://getcomposer.org/commit-deps for more information",
+                path
+            ))
             .into());
         }
 
@@ -1060,13 +1030,10 @@ impl VcsDownloader for GitDownloader {
             msg = format!("Checking out {}", self.get_short_hash(&r#ref));
             remote_url = "%url%".to_string();
             if Platform::get_env("COMPOSER_DISABLE_NETWORK").is_some() {
-                return Err(RuntimeException {
-                    message: format!(
-                        "The required git reference for {} is not in cache and network is disabled, aborting",
-                        target.get_name(),
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "The required git reference for {} is not in cache and network is disabled, aborting",
+                    target.get_name(),
+                ))
                 .into());
             }
         }
@@ -1196,13 +1163,10 @@ impl VcsDownloader for GitDownloader {
                     .as_bool()
                     != Some(true))
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "Source directory {} has unpushed changes on the current branch: \n{}",
-                    path, unpushed
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Source directory {} has unpushed changes on the current branch: \n{}",
+                path, unpushed
+            ))
             .into());
         }
 
@@ -1285,11 +1249,7 @@ impl VcsDownloader for GitDownloader {
                     }
                 }
                 Some("n") => {
-                    return Err(RuntimeException {
-                        message: "Update aborted".to_string(),
-                        code: 0,
-                    }
-                    .into());
+                    return Err(RuntimeException::new("Update aborted".to_string()).into());
                 }
                 Some("v") => {
                     self.inner
@@ -1362,13 +1322,10 @@ impl VcsDownloader for GitDownloader {
                 Some(&path),
             ) != 0
             {
-                return Err(RuntimeException {
-                    message: format!(
-                        "Failed to apply stashed changes:\n\n{}",
-                        self.inner.process.borrow().get_error_output()
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Failed to apply stashed changes:\n\n{}",
+                    self.inner.process.borrow().get_error_output()
+                ))
                 .into());
             }
         }
@@ -1399,14 +1356,11 @@ impl VcsDownloader for GitDownloader {
             .execute_args(&command, &mut output, Some(&path))
             != 0
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "Failed to execute {}\n\n{}",
-                    implode(" ", &command),
-                    self.inner.process.borrow().get_error_output(),
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Failed to execute {}\n\n{}",
+                implode(" ", &command),
+                self.inner.process.borrow().get_error_output(),
+            ))
             .into());
         }
 
diff --git a/crates/shirabe/src/downloader/gzip_downloader.rs b/crates/shirabe/src/downloader/gzip_downloader.rs
index b0494479..9473deff 100644
--- a/crates/shirabe/src/downloader/gzip_downloader.rs
+++ b/crates/shirabe/src/downloader/gzip_downloader.rs
@@ -127,10 +127,7 @@ impl ArchiveDownloader for GzipDownloader {
                 implode(" ", &command),
                 self.inner.process.borrow().get_error_output(),
             );
-            return Err(anyhow::anyhow!(RuntimeException {
-                message: process_error,
-                code: 0
-            }));
+            return Err(RuntimeException::new(process_error).into());
         }
 
         self.extract_using_ext(file, &target_filepath);
diff --git a/crates/shirabe/src/downloader/hg_downloader.rs b/crates/shirabe/src/downloader/hg_downloader.rs
index e555ccf5..dfd25618 100644
--- a/crates/shirabe/src/downloader/hg_downloader.rs
+++ b/crates/shirabe/src/downloader/hg_downloader.rs
@@ -64,10 +64,9 @@ impl VcsDownloader for HgDownloader {
         _prev_package: Option<PackageInterfaceHandle>,
     ) -> anyhow::Result<Option<PhpMixed>> {
         if HgUtils::get_version(&self.inner.process).is_none() {
-            return Err(RuntimeException {
-                message: "hg was not found in your PATH, skipping source download".to_string(),
-                code: 0,
-            }
+            return Err(RuntimeException::new(
+                "hg was not found in your PATH, skipping source download".to_string(),
+            )
             .into());
         }
 
@@ -111,14 +110,11 @@ impl VcsDownloader for HgDownloader {
             shirabe_php_shim::realpath(path).as_deref(),
         ) != 0
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "Failed to execute {}\n\n{}",
-                    command.join(" "),
-                    self.inner.process.borrow().get_error_output()
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Failed to execute {}\n\n{}",
+                command.join(" "),
+                self.inner.process.borrow().get_error_output()
+            ))
             .into());
         }
 
@@ -145,13 +141,10 @@ impl VcsDownloader for HgDownloader {
         ));
 
         if !self.has_metadata_repository(path) {
-            return Err(RuntimeException {
-                message: format!(
-                    "The .hg directory is missing from {}, see https://getcomposer.org/commit-deps for more information",
-                    path
-                ),
-                code: 0,
-            }.into());
+            return Err(RuntimeException::new(format!(
+                "The .hg directory is missing from {}, see https://getcomposer.org/commit-deps for more information",
+                path
+            )).into());
         }
 
         let pull_command = |url: String| -> Vec<String> {
@@ -195,14 +188,11 @@ impl VcsDownloader for HgDownloader {
             shirabe_php_shim::realpath(path).as_deref(),
         ) != 0
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "Failed to execute {}\n\n{}",
-                    command.join(" "),
-                    self.inner.process.borrow().get_error_output()
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Failed to execute {}\n\n{}",
+                command.join(" "),
+                self.inner.process.borrow().get_error_output()
+            ))
             .into());
         }
 
diff --git a/crates/shirabe/src/downloader/max_file_size_exceeded_exception.rs b/crates/shirabe/src/downloader/max_file_size_exceeded_exception.rs
index ebec74df..7a730ff2 100644
--- a/crates/shirabe/src/downloader/max_file_size_exceeded_exception.rs
+++ b/crates/shirabe/src/downloader/max_file_size_exceeded_exception.rs
@@ -1,6 +1,6 @@
 //! ref: composer/src/Composer/Downloader/MaxFileSizeExceededException.php
 
-use crate::downloader::TransportException;
+use crate::downloader::transport_exception::TransportException;
 
 #[derive(Debug)]
 pub struct MaxFileSizeExceededException(pub TransportException);
@@ -11,10 +11,8 @@ impl MaxFileSizeExceededException {
     }
 }
 
-impl std::fmt::Display for MaxFileSizeExceededException {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        self.0.fmt(f)
-    }
-}
-
-impl std::error::Error for MaxFileSizeExceededException {}
+shirabe_php_shim::impl_php_exception!(
+    MaxFileSizeExceededException,
+    0,
+    r"Composer\Downloader\MaxFileSizeExceededException"
+);
diff --git a/crates/shirabe/src/downloader/path_downloader.rs b/crates/shirabe/src/downloader/path_downloader.rs
index f10da72a..9449e74a 100644
--- a/crates/shirabe/src/downloader/path_downloader.rs
+++ b/crates/shirabe/src/downloader/path_downloader.rs
@@ -85,17 +85,14 @@ impl PathDownloader {
         package: PackageInterfaceHandle,
         path: &str,
     ) -> anyhow::Result<String> {
-        let url = package.get_dist_url().ok_or_else(|| RuntimeException {
-            message: format!(
+        let url = package.get_dist_url().ok_or_else(|| {
+            RuntimeException::new(format!(
                 "The package {} has no dist url configured, cannot install.",
                 package.get_pretty_name()
-            ),
-            code: 0,
-        })?;
-        let real_url = realpath(&url).ok_or_else(|| RuntimeException {
-            message: format!("Failed to realpath {}", url),
-            code: 0,
+            ))
         })?;
+        let real_url = realpath(&url)
+            .ok_or_else(|| RuntimeException::new(format!("Failed to realpath {}", url)))?;
 
         if realpath(path).as_deref() == Some(&real_url) {
             return Ok(": Source already present".to_string());
@@ -157,10 +154,7 @@ impl PathDownloader {
             && !self.safe_junctions()
         {
             if !allowed_strategies.contains(&Self::STRATEGY_MIRROR) {
-                return Err(RuntimeException {
-                    message: "You are on an old Windows / old PHP combo which does not allow Composer to use junctions/symlinks and this path repository has symlink:true in its options so copying is not allowed".to_string(),
-                    code: 0,
-                }
+                return Err(RuntimeException::new("You are on an old Windows / old PHP combo which does not allow Composer to use junctions/symlinks and this path repository has symlink:true in its options so copying is not allowed".to_string())
                 .into());
             }
             current_strategy = Self::STRATEGY_MIRROR;
@@ -173,10 +167,7 @@ impl PathDownloader {
             && !function_exists("symlink")
         {
             if !allowed_strategies.contains(&Self::STRATEGY_MIRROR) {
-                return Err(RuntimeException {
-                    message: "Your PHP has the symlink() function disabled which does not allow Composer to use symlinks and this path repository has symlink:true in its options so copying is not allowed".to_string(),
-                    code: 0,
-                }
+                return Err(RuntimeException::new("Your PHP has the symlink() function disabled which does not allow Composer to use symlinks and this path repository has symlink:true in its options so copying is not allowed".to_string())
                 .into());
             }
             current_strategy = Self::STRATEGY_MIRROR;
@@ -243,26 +234,22 @@ impl DownloaderInterface for PathDownloader {
         output: bool,
     ) -> anyhow::Result<Option<PhpMixed>> {
         let path = Filesystem::trim_trailing_slash(path);
-        let url = package.get_dist_url().ok_or_else(|| RuntimeException {
-            message: format!(
+        let url = package.get_dist_url().ok_or_else(|| {
+            RuntimeException::new(format!(
                 "The package {} has no dist url configured, cannot download.",
                 package.get_pretty_name()
-            ),
-            code: 0,
+            ))
         })?;
         let real_url = realpath(&url);
         if real_url.is_none()
             || !file_exists(real_url.as_deref().unwrap_or(""))
             || !is_dir(real_url.as_deref().unwrap_or(""))
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "Source path \"{}\" is not found for package {}",
-                    url,
-                    package.get_name()
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Source path \"{}\" is not found for package {}",
+                url,
+                package.get_name()
+            ))
             .into());
         }
         let real_url = real_url.unwrap();
@@ -282,15 +269,12 @@ impl DownloaderInterface for PathDownloader {
             //
             // Please see https://github.com/composer/composer/pull/5974 and https://github.com/composer/composer/pull/6174
             // for previous attempts that were shut down because they did not work well enough or introduced too many risks.
-            return Err(RuntimeException {
-                message: format!(
-                    "Package {} cannot install to \"{}\" inside its source at \"{}\"",
-                    package.get_name(),
-                    realpath(&path).unwrap_or_default(),
-                    real_url
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Package {} cannot install to \"{}\" inside its source at \"{}\"",
+                package.get_name(),
+                realpath(&path).unwrap_or_default(),
+                real_url
+            ))
             .into());
         }
 
@@ -316,17 +300,14 @@ impl DownloaderInterface for PathDownloader {
         output: bool,
     ) -> anyhow::Result<Option<PhpMixed>> {
         let path = Filesystem::trim_trailing_slash(path);
-        let url = package.get_dist_url().ok_or_else(|| RuntimeException {
-            message: format!(
+        let url = package.get_dist_url().ok_or_else(|| {
+            RuntimeException::new(format!(
                 "The package {} has no dist url configured, cannot install.",
                 package.get_pretty_name()
-            ),
-            code: 0,
-        })?;
-        let real_url = realpath(&url).ok_or_else(|| RuntimeException {
-            message: format!("Failed to realpath {}", url),
-            code: 0,
+            ))
         })?;
+        let real_url = realpath(&url)
+            .ok_or_else(|| RuntimeException::new(format!("Failed to realpath {}", url)))?;
 
         if realpath(&path).as_deref() == Some(&real_url) {
             if output {
@@ -442,13 +423,10 @@ impl DownloaderInterface for PathDownloader {
                         current_strategy = Self::STRATEGY_MIRROR;
                         is_fallback = true;
                     } else {
-                        return Err(RuntimeException {
-                            message: format!(
-                                "Symlink from \"{}\" to \"{}\" failed!",
-                                real_url, path
-                            ),
-                            code: 0,
-                        }
+                        return Err(RuntimeException::new(format!(
+                            "Symlink from \"{}\" to \"{}\" failed!",
+                            real_url, path
+                        ))
                         .into());
                     }
                 }
@@ -537,25 +515,21 @@ impl DownloaderInterface for PathDownloader {
                     true,
                     io_interface::NORMAL,
                 );
-                return Err(RuntimeException {
-                    message: format!(
-                        "Could not reliably remove junction for package {}",
-                        package.get_name()
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Could not reliably remove junction for package {}",
+                    package.get_name()
+                ))
                 .into());
             }
 
             return Ok(None);
         }
 
-        let url = package.get_dist_url().ok_or_else(|| RuntimeException {
-            message: format!(
+        let url = package.get_dist_url().ok_or_else(|| {
+            RuntimeException::new(format!(
                 "The package {} has no dist url configured, cannot remove.",
                 package.get_pretty_name()
-            ),
-            code: 0,
+            ))
         })?;
 
         // ensure that the source path (dist url) is not the same as the install path, which
diff --git a/crates/shirabe/src/downloader/rar_downloader.rs b/crates/shirabe/src/downloader/rar_downloader.rs
index ee0148c7..f4f601bc 100644
--- a/crates/shirabe/src/downloader/rar_downloader.rs
+++ b/crates/shirabe/src/downloader/rar_downloader.rs
@@ -114,39 +114,30 @@ impl ArchiveDownloader for RarDownloader {
                     process_error.as_deref().unwrap_or(""),
                 )
             };
-            return Err(RuntimeException {
-                message: error,
-                code: 0,
-            }
-            .into());
+            return Err(RuntimeException::new(error).into());
         }
 
         let rar_archive = RarArchive::open(file);
         if rar_archive.is_none() {
-            return Err(UnexpectedValueException {
-                message: format!("Could not open RAR archive: {}", file),
-                code: 0,
-            }
+            return Err(UnexpectedValueException::new(format!(
+                "Could not open RAR archive: {}",
+                file
+            ))
             .into());
         }
         let rar_archive = rar_archive.unwrap();
 
         let entries = rar_archive.get_entries();
         if entries.is_none() {
-            return Err(RuntimeException {
-                message: "Could not retrieve RAR archive entries".to_string(),
-                code: 0,
-            }
+            return Err(RuntimeException::new(
+                "Could not retrieve RAR archive entries".to_string(),
+            )
             .into());
         }
 
         for entry in entries.unwrap() {
             if !entry.extract(path) {
-                return Err(RuntimeException {
-                    message: "Could not extract entry".to_string(),
-                    code: 0,
-                }
-                .into());
+                return Err(RuntimeException::new("Could not extract entry".to_string()).into());
             }
         }
 
diff --git a/crates/shirabe/src/downloader/svn_downloader.rs b/crates/shirabe/src/downloader/svn_downloader.rs
index 6a8bdf0e..cb748a93 100644
--- a/crates/shirabe/src/downloader/svn_downloader.rs
+++ b/crates/shirabe/src/downloader/svn_downloader.rs
@@ -75,13 +75,10 @@ impl SvnDownloader {
             Some(path),
         ) != 0
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "Could not reset changes\n\n:{}",
-                    self.inner.process.borrow().get_error_output()
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Could not reset changes\n\n:{}",
+                self.inner.process.borrow().get_error_output()
+            ))
             .into());
         }
 
@@ -96,10 +93,10 @@ impl SvnDownloader {
         path: &str,
     ) -> anyhow::Result<()> {
         if self.get_local_changes(package, path)?.is_some() {
-            return Err(RuntimeException {
-                message: format!("Source directory {} has uncommitted changes.", path),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Source directory {} has uncommitted changes.",
+                path
+            ))
             .into());
         }
 
@@ -143,10 +140,9 @@ impl VcsDownloader for SvnDownloader {
             Some(self.inner.process.clone()),
         );
         if util.binary_version().is_none() {
-            return Err(RuntimeException {
-                message: "svn was not found in your PATH, skipping source download".to_string(),
-                code: 0,
-            }
+            return Err(RuntimeException::new(
+                "svn was not found in your PATH, skipping source download".to_string(),
+            )
             .into());
         }
 
@@ -206,13 +202,10 @@ impl VcsDownloader for SvnDownloader {
         let r#ref = target.get_source_reference();
 
         if !self.has_metadata_repository(path) {
-            return Err(RuntimeException {
-                message: format!(
-                    "The .svn directory is missing from {}, see https://getcomposer.org/commit-deps for more information",
-                    path
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "The .svn directory is missing from {}, see https://getcomposer.org/commit-deps for more information",
+                path
+            ))
             .into());
         }
 
@@ -324,11 +317,7 @@ impl VcsDownloader for SvnDownloader {
                     break;
                 }
                 Some("n") => {
-                    return Err(RuntimeException {
-                        message: "Update aborted".to_string(),
-                        code: 0,
-                    }
-                    .into());
+                    return Err(RuntimeException::new("Update aborted".to_string()).into());
                 }
                 Some("v") => {
                     for line in &changes {
@@ -384,14 +373,11 @@ impl VcsDownloader for SvnDownloader {
                 .execute_args(&command, &mut output, Some(path))
                 != 0
             {
-                return Err(RuntimeException {
-                    message: format!(
-                        "Failed to execute {}\n\n{}",
-                        command.join(" "),
-                        self.inner.process.borrow().get_error_output()
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Failed to execute {}\n\n{}",
+                    command.join(" "),
+                    self.inner.process.borrow().get_error_output()
+                ))
                 .into());
             }
 
@@ -403,10 +389,10 @@ impl VcsDownloader for SvnDownloader {
                     .cloned()
                     .unwrap_or_default()
             } else {
-                return Err(RuntimeException {
-                    message: format!("Unable to determine svn url for path {}", path),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Unable to determine svn url for path {}",
+                    path
+                ))
                 .into());
             };
 
@@ -431,10 +417,11 @@ impl VcsDownloader for SvnDownloader {
             util.set_cache_credentials(self.cache_credentials.get());
             util.execute_local(command.clone(), path, None, self.inner.io.is_verbose())
                 .map_err(|e| {
-                    RuntimeException {
-                        message: format!("Failed to execute {}\n\n{}", command.join(" "), e),
-                        code: 0,
-                    }
+                    RuntimeException::new(format!(
+                        "Failed to execute {}\n\n{}",
+                        command.join(" "),
+                        e
+                    ))
                     .into()
                 })
         } else {
diff --git a/crates/shirabe/src/downloader/transport_exception.rs b/crates/shirabe/src/downloader/transport_exception.rs
index 155a5ce4..da8b4c50 100644
--- a/crates/shirabe/src/downloader/transport_exception.rs
+++ b/crates/shirabe/src/downloader/transport_exception.rs
@@ -1,11 +1,10 @@
 //! ref: composer/src/Composer/Downloader/TransportException.php
 
-use shirabe_php_shim::PhpMixed;
+use shirabe_php_shim::{PhpMixed, RuntimeException};
 
 #[derive(Debug, Clone)]
 pub struct TransportException {
-    pub message: String,
-    pub code: i64,
+    inner: RuntimeException,
     pub(crate) headers: Option<Vec<String>>,
     pub(crate) response: Option<String>,
     pub(crate) status_code: Option<i64>,
@@ -15,8 +14,7 @@ pub struct TransportException {
 impl TransportException {
     pub fn new(message: String, code: i64) -> Self {
         Self {
-            message,
-            code,
+            inner: RuntimeException::with_code(message, code),
             headers: None,
             response: None,
             status_code: None,
@@ -24,20 +22,6 @@ impl TransportException {
         }
     }
 
-    /// PHP exposes ($message, $code = 0) — alias of `new` used at call sites where the
-    /// status/exception code is provided up-front.
-    pub fn new_with_code(message: String, code: i64) -> Self {
-        Self::new(message, code)
-    }
-
-    pub fn get_code(&self) -> i64 {
-        self.code
-    }
-
-    pub fn get_message(&self) -> &str {
-        &self.message
-    }
-
     pub fn set_headers(&mut self, headers: Vec<String>) {
         self.headers = Some(headers);
     }
@@ -71,10 +55,8 @@ impl TransportException {
     }
 }
 
-impl std::fmt::Display for TransportException {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.message)
-    }
-}
-
-impl std::error::Error for TransportException {}
+shirabe_php_shim::impl_php_exception!(
+    TransportException,
+    inner,
+    r"Composer\Downloader\TransportException"
+);
diff --git a/crates/shirabe/src/downloader/vcs_downloader.rs b/crates/shirabe/src/downloader/vcs_downloader.rs
index 45ca0e3a..56bdea60 100644
--- a/crates/shirabe/src/downloader/vcs_downloader.rs
+++ b/crates/shirabe/src/downloader/vcs_downloader.rs
@@ -18,8 +18,9 @@ use crate::util::Filesystem;
 use crate::util::ProcessExecutor;
 use indexmap::IndexMap;
 use shirabe_php_shim::{
-    InvalidArgumentException, PhpMixed, RuntimeException, array_map, array_shift, explode,
-    get_class_err, implode, rawurldecode, realpath, str_replace, strlen, strpos, substr, trim,
+    AnyThrowable, InvalidArgumentException, PhpClass as _, PhpMixed, RuntimeException, array_map,
+    array_shift, explode, implode, rawurldecode, realpath, str_replace, strlen, strpos, substr,
+    trim,
 };
 
 #[derive(Debug)]
@@ -129,13 +130,10 @@ pub trait VcsDownloader:
         prev_package: Option<PackageInterfaceHandle>,
     ) -> anyhow::Result<Option<PhpMixed>> {
         if package.get_source_reference().is_none() {
-            return Err(InvalidArgumentException {
-                message: format!(
-                    "Package {} is missing reference information",
-                    package.get_pretty_name(),
-                ),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "Package {} is missing reference information",
+                package.get_pretty_name(),
+            ))
             .into());
         }
 
@@ -157,7 +155,13 @@ pub trait VcsDownloader:
                     }
                     if self.io().is_debug() {
                         self.io().write_error3(
-                            &format!("Failed: [{}] {}", get_class_err(&e), e),
+                            &format!(
+                                "Failed: [{}] {}",
+                                AnyThrowable::of(e.as_ref())
+                                    .expect("PHP reaches this only with a caught \\Throwable")
+                                    .php_class_name(),
+                                e
+                            ),
                             true,
                             io_interface::NORMAL,
                         );
@@ -232,13 +236,10 @@ pub trait VcsDownloader:
         path: &str,
     ) -> anyhow::Result<Option<PhpMixed>> {
         if package.get_source_reference().is_none() {
-            return Err(InvalidArgumentException {
-                message: format!(
-                    "Package {} is missing reference information",
-                    package.get_pretty_name(),
-                ),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "Package {} is missing reference information",
+                package.get_pretty_name(),
+            ))
             .into());
         }
 
@@ -264,7 +265,13 @@ pub trait VcsDownloader:
                     }
                     if self.io().is_debug() {
                         self.io().write_error3(
-                            &format!("Failed: [{}] {}", get_class_err(&e), e),
+                            &format!(
+                                "Failed: [{}] {}",
+                                AnyThrowable::of(e.as_ref())
+                                    .expect("PHP reaches this only with a caught \\Throwable")
+                                    .php_class_name(),
+                                e
+                            ),
                             true,
                             io_interface::NORMAL,
                         );
@@ -292,13 +299,10 @@ pub trait VcsDownloader:
         path: &str,
     ) -> anyhow::Result<Option<PhpMixed>> {
         if target.get_source_reference().is_none() {
-            return Err(InvalidArgumentException {
-                message: format!(
-                    "Package {} is missing reference information",
-                    target.get_pretty_name(),
-                ),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "Package {} is missing reference information",
+                target.get_pretty_name(),
+            ))
             .into());
         }
 
@@ -333,7 +337,13 @@ pub trait VcsDownloader:
                     }
                     if self.io().is_debug() {
                         self.io().write_error3(
-                            &format!("Failed: [{}] {}", get_class_err(&e), e),
+                            &format!(
+                                "Failed: [{}] {}",
+                                AnyThrowable::of(e.as_ref())
+                                    .expect("PHP reaches this only with a caught \\Throwable")
+                                    .php_class_name(),
+                                e
+                            ),
                             true,
                             io_interface::NORMAL,
                         );
@@ -400,10 +410,10 @@ pub trait VcsDownloader:
 
         let result = Filesystem::remove_directory_async_via(self.filesystem(), path).await?;
         if !result {
-            return Err(RuntimeException {
-                message: format!("Could not completely delete {}, aborting.", path),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Could not completely delete {}, aborting.",
+                path
+            ))
             .into());
         }
 
@@ -441,10 +451,10 @@ pub trait VcsDownloader:
     ) -> anyhow::Result<Option<PhpMixed>> {
         // the default implementation just fails if there are any changes, override in child classes to provide stash-ability
         if self.get_local_changes(package, path)?.is_some() {
-            return Err(RuntimeException {
-                message: format!("Source directory {} has uncommitted changes.", path),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Source directory {} has uncommitted changes.",
+                path
+            ))
             .into());
         }
 
diff --git a/crates/shirabe/src/downloader/zip_downloader.rs b/crates/shirabe/src/downloader/zip_downloader.rs
index 8870194c..84ed4c9e 100644
--- a/crates/shirabe/src/downloader/zip_downloader.rs
+++ b/crates/shirabe/src/downloader/zip_downloader.rs
@@ -10,6 +10,7 @@ use crate::util::Platform;
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
 use shirabe_external_packages::symfony::process::ExecutableFinder;
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     CmpOp, DIRECTORY_SEPARATOR, ErrorException, PhpMixed, RuntimeException,
     UnexpectedValueException, ZipArchive, bin2hex, class_exists, file_exists, file_get_contents,
@@ -146,13 +147,10 @@ impl ZipDownloader {
                         .borrow()
                         .contains_key(&package.get_name())
                     {
-                        return Err(RuntimeException {
-                            message: format!(
-                                "Failed to extract {} as the installation was aborted by another package operation.",
-                                package.get_name()
-                            ),
-                            code: 0,
-                        }
+                        return Err(RuntimeException::new(format!(
+                            "Failed to extract {} as the installation was aborted by another package operation.",
+                            package.get_name()
+                        ))
                         .into());
                     }
 
@@ -162,19 +160,16 @@ impl ZipDownloader {
 
                     return self
                         .try_fallback(
-                            RuntimeException {
-                                message: format!(
-                                    "Failed to extract {}: ({}) {}\n\n{}",
-                                    package.get_name(),
-                                    process
-                                        .get_exit_code()
-                                        .map(|c| c.to_string())
-                                        .unwrap_or_default(),
-                                    command.join(" "),
-                                    output
-                                ),
-                                code: 0,
-                            }
+                            RuntimeException::new(format!(
+                                "Failed to extract {}: ({}) {}\n\n{}",
+                                package.get_name(),
+                                process
+                                    .get_exit_code()
+                                    .map(|c| c.to_string())
+                                    .unwrap_or_default(),
+                                command.join(" "),
+                                output
+                            ))
                             .into(),
                             is_last_chance,
                             file,
@@ -337,13 +332,10 @@ impl ZipDownloader {
                             && total_size > archive_sz * 100
                             && total_size > 50 * 1024 * 1024
                         {
-                            return Err(RuntimeException {
-                                message: format!(
-                                    "Invalid zip file for \"{}\" with compression ratio >99% (possible zip bomb)",
-                                    package.get_name(),
-                                ),
-                                code: 0,
-                            }.into());
+                            return Err(RuntimeException::new(format!(
+                                "Invalid zip file for \"{}\" with compression ratio >99% (possible zip bomb)",
+                                package.get_name(),
+                            )).into());
                         }
                     }
 
@@ -354,32 +346,26 @@ impl ZipDownloader {
                         return Ok(None);
                     }
 
-                    Err(RuntimeException {
-                        message: format!(
-                            "There was an error extracting the ZIP file for \"{}\", it is either corrupted or using an invalid format.",
-                            package.get_name(),
-                        ),
-                        code: 0,
-                    }.into())
+                    Err(RuntimeException::new(format!(
+                        "There was an error extracting the ZIP file for \"{}\", it is either corrupted or using an invalid format.",
+                        package.get_name(),
+                    )).into())
                 }
-                Err(code) => Err(UnexpectedValueException {
-                    message: self.get_error_message(code, file).trim_end().to_string(),
+                Err(code) => Err(UnexpectedValueException::with_code(
+                    self.get_error_message(code, file).trim_end().to_string(),
                     code,
-                }
+                )
                 .into()),
             }
         })();
 
         result.map_err(|e| {
-            if let Some(err) = e.downcast_ref::<ErrorException>() {
-                RuntimeException {
-                    message: format!(
-                        "The archive for \"{}\" may contain identical file names with different capitalization (which fails on case insensitive filesystems): {}",
-                        package.get_name(),
-                        err.message,
-                    ),
-                    code: 0,
-                }.into()
+            if let Some(err) = e.catch::<ErrorException>() {
+                RuntimeException::new(format!(
+                    "The archive for \"{}\" may contain identical file names with different capitalization (which fails on case insensitive filesystems): {}",
+                    package.get_name(),
+                    err.get_message(),
+                )).into()
             } else {
                 e
             }
@@ -578,11 +564,7 @@ impl crate::downloader::DownloaderInterface for ZipDownloader {
                     ini_message
                 )
             };
-            return Err(RuntimeException {
-                message: error,
-                code: 0,
-            }
-            .into());
+            return Err(RuntimeException::new(error).into());
         }
 
         {