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>

10 files changed, 195 insertions, 277 deletions

diff --git a/crates/shirabe/src/repository/vcs/forgejo_driver.rs b/crates/shirabe/src/repository/vcs/forgejo_driver.rs
index 0719701f..e4ebe379 100644
--- a/crates/shirabe/src/repository/vcs/forgejo_driver.rs
+++ b/crates/shirabe/src/repository/vcs/forgejo_driver.rs
@@ -16,6 +16,7 @@ use crate::util::ForgejoUrl;
 use crate::util::http::Response;
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     PhpMixed, RuntimeException, base64_decode, explode, extension_loaded, php_regex, urlencode,
 };
@@ -107,7 +108,7 @@ impl ForgejoDriver {
         );
         let response = self
             .get_contents(&resource_url, false)
-            .map_err(|e| anyhow::anyhow!("{}", e.message))?;
+            .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?;
         let mut resource = response.decode_json()?;
 
         // The Forgejo contents API only returns files up to 1MB as base64 encoded files;
@@ -134,7 +135,7 @@ impl ForgejoDriver {
             if let Some(git_url) = git_url {
                 resource = self
                     .get_contents(&git_url, false)
-                    .map_err(|e| anyhow::anyhow!("{}", e.message))?
+                    .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?
                     .decode_json()?;
             }
         }
@@ -157,22 +158,22 @@ impl ForgejoDriver {
             Some(b64) => match base64_decode(&b64) {
                 Some(bytes) => match String::from_utf8(bytes) {
                     Ok(s) => Ok(Some(s)),
-                    Err(_) => Err(RuntimeException {
-                        message: format!("Could not retrieve {} for {}", file, identifier),
-                        code: 0,
-                    }
+                    Err(_) => Err(RuntimeException::new(format!(
+                        "Could not retrieve {} for {}",
+                        file, identifier
+                    ))
                     .into()),
                 },
-                None => Err(RuntimeException {
-                    message: format!("Could not retrieve {} for {}", file, identifier),
-                    code: 0,
-                }
+                None => Err(RuntimeException::new(format!(
+                    "Could not retrieve {} for {}",
+                    file, identifier
+                ))
                 .into()),
             },
-            None => Err(RuntimeException {
-                message: format!("Could not retrieve {} for {}", file, identifier),
-                code: 0,
-            }
+            None => Err(RuntimeException::new(format!(
+                "Could not retrieve {} for {}",
+                file, identifier
+            ))
             .into()),
         }
     }
@@ -193,7 +194,7 @@ impl ForgejoDriver {
         );
         let commit = self
             .get_contents(&resource_url, false)
-            .map_err(|e| anyhow::anyhow!("{}", e.message))?
+            .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?
             .decode_json()?;
 
         let date_str = if let PhpMixed::Array(ref arr) = commit {
@@ -208,9 +209,8 @@ impl ForgejoDriver {
             None
         };
 
-        let date_str = date_str.ok_or_else(|| RuntimeException {
-            message: format!("Could not parse commit date for {}", identifier),
-            code: 0,
+        let date_str = date_str.ok_or_else(|| {
+            RuntimeException::new(format!("Could not parse commit date for {}", identifier))
         })?;
 
         let date: chrono::DateTime<chrono::FixedOffset> = shirabe_php_shim::date_create(&date_str)?;
@@ -243,7 +243,7 @@ impl ForgejoDriver {
             while let Some(url) = resource {
                 let response = self
                     .get_contents(&url, false)
-                    .map_err(|e| anyhow::anyhow!("{}", e.message))?;
+                    .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?;
                 let branch_data = response.decode_json()?;
                 if let PhpMixed::List(ref list) = branch_data {
                     for branch in list {
@@ -286,7 +286,7 @@ impl ForgejoDriver {
             while let Some(url) = resource {
                 let response = self
                     .get_contents(&url, false)
-                    .map_err(|e| anyhow::anyhow!("{}", e.message))?;
+                    .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?;
                 let tags_data = response.decode_json()?;
                 if let PhpMixed::List(ref list) = tags_data {
                     for tag in list {
@@ -599,7 +599,7 @@ impl ForgejoDriver {
         &mut self,
         url: &str,
         fetching_repo_data: bool,
-    ) -> anyhow::Result<Response, TransportException> {
+    ) -> anyhow::Result<Response, Box<TransportException>> {
         match self.inner.get_contents(url) {
             Ok(response) => Ok(response),
             Err(e) => match e.get_code() {
@@ -610,14 +610,7 @@ impl ForgejoDriver {
 
                     if !self.inner.io.is_interactive() {
                         self.attempt_clone_fallback()
-                            .map_err(|inner_e| TransportException {
-                                message: inner_e.to_string(),
-                                code: 0,
-                                headers: None,
-                                response: None,
-                                status_code: None,
-                                response_info: vec![],
-                            })?;
+                            .map_err(|inner_e| TransportException::new(inner_e.to_string(), 0))?;
 
                         return Ok(Response::new(
                             "dummy".to_string(),
@@ -645,14 +638,7 @@ impl ForgejoDriver {
                         );
                         let auth_result = forgejo
                             .authorize_o_auth_interactively(&origin_url, message.as_deref())
-                            .map_err(|inner_e| TransportException {
-                                message: inner_e.to_string(),
-                                code: 0,
-                                headers: None,
-                                response: None,
-                                status_code: None,
-                                response_info: vec![],
-                            })?;
+                            .map_err(|inner_e| TransportException::new(inner_e.to_string(), 0))?;
 
                         if let Ok(true) = auth_result {
                             return self.inner.get_contents(url);
@@ -734,7 +720,7 @@ impl crate::repository::vcs::VcsDriverInterface for ForgejoDriver {
         match self.get_composer_information(identifier) {
             Ok(info) => Ok(info.is_some()),
             Err(e) => {
-                if e.downcast_ref::<TransportException>().is_some() {
+                if e.is_instanceof::<TransportException>() {
                     Ok(false)
                 } else {
                     Err(e)
diff --git a/crates/shirabe/src/repository/vcs/fossil_driver.rs b/crates/shirabe/src/repository/vcs/fossil_driver.rs
index 1b61ed4d..3795d1ca 100644
--- a/crates/shirabe/src/repository/vcs/fossil_driver.rs
+++ b/crates/shirabe/src/repository/vcs/fossil_driver.rs
@@ -12,6 +12,7 @@ use crate::util::ProcessExecutor;
 use chrono::{DateTime, FixedOffset, Utc};
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::Preg;
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     PhpMixed, RuntimeException, dirname, is_dir, is_file, is_writable, php_regex,
 };
@@ -77,10 +78,7 @@ impl FossilDriver {
                 .unwrap_or("")
                 .to_string();
             if !Cache::is_usable(&cache_repo_dir) || !Cache::is_usable(&cache_vcs_dir) {
-                return Err(RuntimeException {
-                    message: "FossilDriver requires a usable cache directory, and it looks like you set it to be disabled".to_string(),
-                    code: 0,
-                }
+                return Err(RuntimeException::new("FossilDriver requires a usable cache directory, and it looks like you set it to be disabled".to_string())
                 .into());
             }
 
@@ -105,13 +103,10 @@ impl FossilDriver {
             None,
         ) != 0
         {
-            return Err(RuntimeException {
-                message: format!(
-                    "fossil was not found, check that it is installed and in your PATH env.\n\n{}",
-                    self.inner.process.borrow().get_error_output()
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "fossil was not found, check that it is installed and in your PATH env.\n\n{}",
+                self.inner.process.borrow().get_error_output()
+            ))
             .into());
         }
         Ok(())
@@ -124,13 +119,10 @@ impl FossilDriver {
         fs.ensure_directory_exists(&self.checkout_dir)?;
 
         if !is_writable(dirname(&self.checkout_dir)) {
-            return Err(RuntimeException {
-                message: format!(
-                    "Can not clone {} to access package information. The \"{}\" directory is not writable by the current user.",
-                    self.inner.url, self.checkout_dir
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Can not clone {} to access package information. The \"{}\" directory is not writable by the current user.",
+                self.inner.url, self.checkout_dir
+            ))
             .into());
         }
 
@@ -173,13 +165,10 @@ impl FossilDriver {
             ) != 0
             {
                 let output = self.inner.process.borrow().get_error_output().to_string();
-                return Err(RuntimeException {
-                    message: format!(
-                        "Failed to clone {} to repository {}\n\n{}",
-                        self.inner.url, repo_file, output
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Failed to clone {} to repository {}\n\n{}",
+                    self.inner.url, repo_file, output
+                ))
                 .into());
             }
 
@@ -192,13 +181,10 @@ impl FossilDriver {
             ) != 0
             {
                 let output = self.inner.process.borrow().get_error_output().to_string();
-                return Err(RuntimeException {
-                    message: format!(
-                        "Failed to open repository {} in {}\n\n{}",
-                        repo_file, self.checkout_dir, output
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Failed to open repository {} in {}\n\n{}",
+                    repo_file, self.checkout_dir, output
+                ))
                 .into());
             }
         }
@@ -231,13 +217,10 @@ impl FossilDriver {
 
     pub fn get_file_content(&self, file: &str, identifier: &str) -> anyhow::Result<Option<String>> {
         if identifier.starts_with('-') {
-            return Err(RuntimeException {
-                message: format!(
-                    "Invalid fossil identifier detected. Identifier must not start with a -, given: {}",
-                    identifier
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Invalid fossil identifier detected. Identifier must not start with a -, given: {}",
+                identifier
+            ))
             .into());
         }
 
@@ -420,7 +403,7 @@ impl crate::repository::vcs::VcsDriverInterface for FossilDriver {
         match self.get_composer_information(identifier) {
             Ok(info) => Ok(info.is_some()),
             Err(e) => {
-                if e.downcast_ref::<TransportException>().is_some() {
+                if e.is_instanceof::<TransportException>() {
                     Ok(false)
                 } else {
                     Err(e)
diff --git a/crates/shirabe/src/repository/vcs/git_bitbucket_driver.rs b/crates/shirabe/src/repository/vcs/git_bitbucket_driver.rs
index 8fe93018..d833b576 100644
--- a/crates/shirabe/src/repository/vcs/git_bitbucket_driver.rs
+++ b/crates/shirabe/src/repository/vcs/git_bitbucket_driver.rs
@@ -16,6 +16,7 @@ use crate::util::http::Response;
 use chrono::{DateTime, FixedOffset};
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     InvalidArgumentException, LogicException, PhpMixed, RuntimeException, array_key_exists,
     array_search_mixed, extension_loaded, http_build_query_mixed, implode, is_array, php_regex,
@@ -90,13 +91,10 @@ impl GitBitbucketDriver {
             &self.inner.url,
             Some(&mut m),
         ) {
-            return Err(InvalidArgumentException {
-                message: format!(
-                    "The Bitbucket repository URL {} is invalid. It must be the HTTPS URL of a Bitbucket repository.",
-                    self.inner.url.clone(),
-                ),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "The Bitbucket repository URL {} is invalid. It must be the HTTPS URL of a Bitbucket repository.",
+                self.inner.url.clone(),
+            ))
             .into());
         }
 
@@ -706,7 +704,7 @@ impl GitBitbucketDriver {
                         if !self.inner.io.has_authentication(&self.inner.origin_url)
                             && bitbucket_util.authorize_oauth(&self.inner.origin_url)
                         {
-                            return self.inner.get_contents(url).map_err(anyhow::Error::from);
+                            return self.inner.get_contents(url).map_err(|e| (*e).into());
                         }
 
                         if !self.inner.io.is_interactive() && fetching_repo_data {
@@ -722,7 +720,7 @@ impl GitBitbucketDriver {
                     }
                 }
 
-                Err(e.into())
+                Err((*e).into())
             }
         }
     }
@@ -742,7 +740,7 @@ impl GitBitbucketDriver {
         match self.setup_fallback_driver(&self.generate_ssh_url()) {
             Ok(()) => Ok(true),
             Err(e) => {
-                if e.downcast_ref::<RuntimeException>().is_some() {
+                if e.is_instanceof::<RuntimeException>() {
                     self.fallback_driver = None;
 
                     self.inner.io.write_error(&format!(
@@ -799,11 +797,10 @@ impl GitBitbucketDriver {
         if self.root_identifier.is_none() {
             if !self.get_repo_data()? {
                 if self.fallback_driver.is_none() {
-                    return Err(LogicException {
-                        message: "A fallback driver should be setup if getRepoData returns false"
+                    return Err(LogicException::new(
+                        "A fallback driver should be setup if getRepoData returns false"
                             .to_string(),
-                        code: 0,
-                    }
+                    )
                     .into());
                 }
 
@@ -811,13 +808,10 @@ impl GitBitbucketDriver {
             }
 
             if self.vcs_type.as_deref() != Some("git") {
-                return Err(RuntimeException {
-                    message: format!(
-                        "{} does not appear to be a git repository, use {} but remember that Bitbucket no longer supports the mercurial repositories. https://bitbucket.org/blog/sunsetting-mercurial-support-in-bitbucket",
-                        self.inner.url, self.clone_https_url
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "{} does not appear to be a git repository, use {} but remember that Bitbucket no longer supports the mercurial repositories. https://bitbucket.org/blog/sunsetting-mercurial-support-in-bitbucket",
+                    self.inner.url, self.clone_https_url
+                ))
                 .into());
             }
 
@@ -918,7 +912,7 @@ impl crate::repository::vcs::VcsDriverInterface for GitBitbucketDriver {
         match self.get_composer_information(identifier) {
             Ok(info) => Ok(info.is_some()),
             Err(e) => {
-                if e.downcast_ref::<TransportException>().is_some() {
+                if e.is_instanceof::<TransportException>() {
                     Ok(false)
                 } else {
                     Err(e)
diff --git a/crates/shirabe/src/repository/vcs/git_driver.rs b/crates/shirabe/src/repository/vcs/git_driver.rs
index 1376ebbc..9f8a6b32 100644
--- a/crates/shirabe/src/repository/vcs/git_driver.rs
+++ b/crates/shirabe/src/repository/vcs/git_driver.rs
@@ -15,6 +15,7 @@ use chrono::TimeZone;
 use chrono::{DateTime, FixedOffset, Utc};
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     InvalidArgumentException, RuntimeException, dirname, is_dir, is_writable, realpath,
     sys_get_temp_dir,
@@ -52,13 +53,10 @@ impl GitDriver {
         if Filesystem::is_local_path(&self.inner.url) {
             self.inner.url = Preg::replace(php_regex!(r"{[\\/]\.git/?$}"), "", &self.inner.url);
             if !is_dir(&self.inner.url) {
-                return Err(RuntimeException {
-                    message: format!(
-                        "Failed to read package information from {} as the path does not exist",
-                        self.inner.url
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Failed to read package information from {} as the path does not exist",
+                    self.inner.url
+                ))
                 .into());
             }
             self.repo_dir = self.inner.url.clone();
@@ -73,10 +71,7 @@ impl GitDriver {
                 .unwrap_or("")
                 .to_string();
             if !Cache::is_usable(&cache_vcs_dir) {
-                return Err(RuntimeException {
-                    message: "GitDriver requires a usable cache directory, and it looks like you set it to be disabled".to_string(),
-                    code: 0,
-                }
+                return Err(RuntimeException::new("GitDriver requires a usable cache directory, and it looks like you set it to be disabled".to_string())
                 .into());
             }
 
@@ -96,25 +91,19 @@ impl GitDriver {
             fs.ensure_directory_exists(&dirname(&self.repo_dir))?;
 
             if !is_writable(dirname(&self.repo_dir)) {
-                return Err(RuntimeException {
-                    message: format!(
-                        "Can not clone {} to access package information. The \"{}\" directory is not writable by the current user.",
-                        self.inner.url,
-                        dirname(&self.repo_dir)
-                    ),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Can not clone {} to access package information. The \"{}\" directory is not writable by the current user.",
+                    self.inner.url,
+                    dirname(&self.repo_dir)
+                ))
                 .into());
             }
 
             if Preg::is_match(php_regex!(r"{^ssh://[^@]+@[^:]+:[^0-9]+}"), &self.inner.url) {
-                return Err(InvalidArgumentException {
-                    message: format!(
-                        "The source URL {} is invalid, ssh URLs should have a port number after \":\".\nUse ssh://git@example.com:22/path or just git@example.com:path if you do not want to provide a password or custom port.",
-                        self.inner.url
-                    ),
-                    code: 0,
-                }
+                return Err(InvalidArgumentException::new(format!(
+                    "The source URL {} is invalid, ssh URLs should have a port number after \":\".\nUse ssh://git@example.com:22/path or just git@example.com:path if you do not want to provide a password or custom port.",
+                    self.inner.url
+                ))
                 .into());
             }
 
@@ -126,13 +115,10 @@ impl GitDriver {
             );
             if !git_util.sync_mirror(&self.inner.url, &self.repo_dir)? {
                 if !is_dir(&self.repo_dir) {
-                    return Err(RuntimeException {
-                        message: format!(
-                            "Failed to clone {} to read package information from it",
-                            self.inner.url
-                        ),
-                        code: 0,
-                    }
+                    return Err(RuntimeException::new(format!(
+                        "Failed to clone {} to read package information from it",
+                        self.inner.url
+                    ))
                     .into());
                 }
                 self.inner.io.write_error3(&format!(
@@ -250,13 +236,10 @@ impl GitDriver {
         identifier: &str,
     ) -> anyhow::Result<Option<String>> {
         if identifier.starts_with('-') {
-            return Err(RuntimeException {
-                message: format!(
-                    "Invalid git identifier detected. Identifier must not start with a -, given: {}",
-                    identifier
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Invalid git identifier detected. Identifier must not start with a -, given: {}",
+                identifier
+            ))
             .into());
         }
 
@@ -283,13 +266,10 @@ impl GitDriver {
         identifier: &str,
     ) -> anyhow::Result<Option<DateTime<FixedOffset>>> {
         if identifier.starts_with('-') {
-            return Err(RuntimeException {
-                message: format!(
-                    "Invalid git identifier detected. Identifier must not start with a -, given: {}",
-                    identifier
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Invalid git identifier detected. Identifier must not start with a -, given: {}",
+                identifier
+            ))
             .into());
         }
 
@@ -459,7 +439,7 @@ impl GitDriver {
         ) {
             Ok(_) => Ok(true),
             Err(e) => {
-                if e.downcast_ref::<RuntimeException>().is_some() {
+                if e.is_instanceof::<RuntimeException>() {
                     Ok(false)
                 } else {
                     Err(e)
@@ -543,7 +523,7 @@ impl crate::repository::vcs::VcsDriverInterface for GitDriver {
         match self.get_composer_information(identifier) {
             Ok(info) => Ok(info.is_some()),
             Err(e) => {
-                if e.downcast_ref::<TransportException>().is_some() {
+                if e.is_instanceof::<TransportException>() {
                     Ok(false)
                 } else {
                     Err(e)
diff --git a/crates/shirabe/src/repository/vcs/github_driver.rs b/crates/shirabe/src/repository/vcs/github_driver.rs
index d656ae61..72bcc8ae 100644
--- a/crates/shirabe/src/repository/vcs/github_driver.rs
+++ b/crates/shirabe/src/repository/vcs/github_driver.rs
@@ -15,6 +15,7 @@ use crate::util::http::Response;
 use chrono::{DateTime, FixedOffset};
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     InvalidArgumentException, PhpMixed, RuntimeException, array_diff, array_key_exists, array_map,
     array_search_mixed, base64_decode, basename, empty, explode, extension_loaded, in_array_loose,
@@ -77,13 +78,10 @@ impl GitHubDriver {
             &self.inner.url,
             Some(&mut match_),
         ) {
-            return Err(InvalidArgumentException {
-                message: format!(
-                    "The GitHub repository URL {} is invalid.",
-                    self.inner.url.clone(),
-                ),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "The GitHub repository URL {} is invalid.",
+                self.inner.url.clone(),
+            ))
             .into());
         }
 
@@ -737,7 +735,7 @@ impl GitHubDriver {
         );
         let mut resource = self
             .get_contents(&resource_url, false)
-            .map_err(|e| anyhow::anyhow!("{}", e.message))?
+            .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?
             .decode_json()?;
 
         // The GitHub contents API only returns files up to 1MB as base64 encoded files
@@ -765,7 +763,7 @@ impl GitHubDriver {
                 .to_string();
             resource = self
                 .get_contents(&git_url, false)
-                .map_err(|e| anyhow::anyhow!("{}", e.message))?
+                .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?
                 .decode_json()?;
         }
 
@@ -789,10 +787,10 @@ impl GitHubDriver {
         let content = match content {
             Some(c) => String::from_utf8_lossy(&c).to_string(),
             None => {
-                return Err(RuntimeException {
-                    message: format!("Could not retrieve {} for {}", file, identifier),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(format!(
+                    "Could not retrieve {} for {}",
+                    file, identifier
+                ))
                 .into());
             }
         };
@@ -817,7 +815,7 @@ impl GitHubDriver {
         );
         let commit = self
             .get_contents(&resource, false)
-            .map_err(|e| anyhow::anyhow!("{}", e.message))?
+            .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?
             .decode_json()?;
 
         let date_str = match commit {
@@ -853,7 +851,7 @@ impl GitHubDriver {
             loop {
                 let response = self
                     .get_contents(resource.as_deref().unwrap_or(""), false)
-                    .map_err(|e| anyhow::anyhow!("{}", e.message))?;
+                    .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?;
                 let tags_data = response.decode_json()?;
                 if let PhpMixed::List(ref list) = tags_data {
                     for tag in list {
@@ -903,7 +901,7 @@ impl GitHubDriver {
             loop {
                 let response = self
                     .get_contents(resource.as_deref().unwrap_or(""), false)
-                    .map_err(|e| anyhow::anyhow!("{}", e.message))?;
+                    .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?;
                 let branch_data = response.decode_json()?;
                 if let PhpMixed::List(ref list) = branch_data {
                     for branch in list {
@@ -1015,7 +1013,7 @@ impl GitHubDriver {
         &mut self,
         url: &str,
         fetching_repo_data: bool,
-    ) -> anyhow::Result<Response, TransportException> {
+    ) -> anyhow::Result<Response, Box<TransportException>> {
         let response_result = self.inner.get_contents(url);
         match response_result {
             Ok(r) => Ok(r),
@@ -1028,7 +1026,7 @@ impl GitHubDriver {
                 )
                 .map_err(|err| TransportException::new(err.to_string(), 0))?;
 
-                match e.code {
+                match e.get_code() {
                     401 | 404 => {
                         // try to authorize only if we are fetching the main /repos/foo/bar data, otherwise it must be a real 404
                         if !fetching_repo_data {
@@ -1178,10 +1176,10 @@ impl GitHubDriver {
                 };
             }
             Err(e) => {
-                if e.code == 499 {
+                if e.get_code() == 499 {
                     self.attempt_clone_fallback(Some(&e))?;
                 } else {
-                    return Err(e.into());
+                    return Err((*e).into());
                 }
             }
         }
@@ -1232,13 +1230,11 @@ impl GitHubDriver {
         e: Option<&TransportException>,
     ) -> anyhow::Result<bool> {
         if !self.allow_git_fallback {
-            return Err(RuntimeException {
-                message: format!(
-                    "Fallback to git driver disabled{}",
-                    e.map(|e| format!(": {}", e.message)).unwrap_or_default()
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Fallback to git driver disabled{}",
+                e.map(|e| format!(": {}", e.get_message()))
+                    .unwrap_or_default()
+            ))
             .into());
         }
 
@@ -1269,11 +1265,9 @@ impl GitHubDriver {
 
     pub(crate) fn setup_git_driver(&mut self, url: &str) -> anyhow::Result<()> {
         if !self.allow_git_fallback {
-            return Err(RuntimeException {
-                message: "Fallback to git driver disabled".to_string(),
-                code: 0,
-            }
-            .into());
+            return Err(
+                RuntimeException::new("Fallback to git driver disabled".to_string()).into(),
+            );
         }
         let mut repo_config: IndexMap<String, PhpMixed> = IndexMap::new();
         repo_config.insert("url".to_string(), PhpMixed::String(url.to_string()));
@@ -1377,7 +1371,7 @@ impl crate::repository::vcs::VcsDriverInterface for GitHubDriver {
         match self.get_composer_information(identifier) {
             Ok(info) => Ok(info.is_some()),
             Err(e) => {
-                if e.downcast_ref::<TransportException>().is_some() {
+                if e.is_instanceof::<TransportException>() {
                     Ok(false)
                 } else {
                     Err(e)
diff --git a/crates/shirabe/src/repository/vcs/gitlab_driver.rs b/crates/shirabe/src/repository/vcs/gitlab_driver.rs
index 5fe513f6..8432ed65 100644
--- a/crates/shirabe/src/repository/vcs/gitlab_driver.rs
+++ b/crates/shirabe/src/repository/vcs/gitlab_driver.rs
@@ -16,6 +16,7 @@ use crate::util::http::Response;
 use chrono::{DateTime, FixedOffset};
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     InvalidArgumentException, LogicException, PhpMixed, RuntimeException, array_search_mixed,
     array_shift, ctype_alnum, empty, explode, extension_loaded, implode, in_array_loose, is_array,
@@ -82,13 +83,10 @@ impl GitLabDriver {
     pub fn initialize(&mut self) -> anyhow::Result<()> {
         let mut match_: IndexMap<CaptureKey, String> = IndexMap::new();
         if !Preg::is_match3(Self::URL_REGEX, &self.inner.url, Some(&mut match_)) {
-            return Err(InvalidArgumentException {
-                message: format!(
-                    "The GitLab repository URL {} is invalid. It must be the HTTP URL of a GitLab project.",
-                    self.inner.url.clone(),
-                ),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "The GitLab repository URL {} is invalid. It must be the HTTP URL of a GitLab project.",
+                self.inner.url.clone(),
+            ))
             .into());
         }
 
@@ -134,13 +132,10 @@ impl GitLabDriver {
         let origin = match origin {
             Some(o) => o,
             None => {
-                return Err(LogicException {
-                    message: format!(
-                        "It should not be possible to create a gitlab driver with an unparsable origin URL ({})",
-                        self.inner.url
-                    ),
-                    code: 0,
-                }
+                return Err(LogicException::new(format!(
+                    "It should not be possible to create a gitlab driver with an unparsable origin URL ({})",
+                    self.inner.url
+                ))
                 .into());
             }
         };
@@ -153,10 +148,9 @@ impl GitLabDriver {
         {
             // https treated as a synonym for http.
             if !matches!(protocol, "git" | "http" | "https") {
-                return Err(RuntimeException {
-                    message: "gitlab-protocol must be one of git, http.".to_string(),
-                    code: 0,
-                }
+                return Err(RuntimeException::new(
+                    "gitlab-protocol must be one of git, http.".to_string(),
+                )
                 .into());
             }
             self.protocol = if protocol == "git" {
@@ -424,8 +418,8 @@ impl GitLabDriver {
         let content = match self.get_contents(&resource, false) {
             Ok(response) => response.get_body().map(|s| s.to_string()),
             Err(e) => {
-                if e.code != 404 {
-                    return Err(e.into());
+                if e.get_code() != 404 {
+                    return Err((*e).into());
                 }
 
                 return Ok(None);
@@ -617,7 +611,7 @@ impl GitLabDriver {
         loop {
             let response = self
                 .get_contents(resource.as_deref().unwrap_or(""), false)
-                .map_err(|e| anyhow::anyhow!("{}", e.message))?;
+                .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?;
             let data = response.decode_json()?;
 
             if let PhpMixed::List(ref list) = data {
@@ -676,7 +670,7 @@ impl GitLabDriver {
         let resource = self.get_api_url();
         let project = self
             .get_contents(&resource, true)
-            .map_err(|e| anyhow::anyhow!("{}", e.message))?
+            .map_err(|e| anyhow::anyhow!("{}", e.get_message()))?
             .decode_json()?;
         self.project = match project {
             PhpMixed::Array(m) => Some(m),
@@ -769,7 +763,7 @@ impl GitLabDriver {
         &mut self,
         url: &str,
         fetching_repo_data: bool,
-    ) -> anyhow::Result<Response, TransportException> {
+    ) -> anyhow::Result<Response, Box<TransportException>> {
         let response_result = self.inner.get_contents(url);
         match response_result {
             Ok(response) => {
@@ -839,21 +833,21 @@ impl GitLabDriver {
                             .and_then(|v| v.as_string())
                             == Some("disabled")
                         {
-                            return Err(TransportException::new(
+                            return Err(Box::new(TransportException::new(
                                 "The GitLab repository is disabled in the project".to_string(),
                                 400,
-                            ));
+                            )));
                         }
 
                         if !empty(&json_map.get("id").cloned().unwrap_or(PhpMixed::Null)) {
                             self.is_private = false;
                         }
 
-                        return Err(TransportException::new(
+                        return Err(Box::new(TransportException::new(
                             "GitLab API seems to not be authenticated as it did not return a default_branch"
                                     .to_string(),
                             401,
-                        ));
+                        )));
                     }
                 }
 
@@ -868,7 +862,7 @@ impl GitLabDriver {
                 )
                 .map_err(|err| TransportException::new(err.to_string(), 0))?;
 
-                match e.code {
+                match e.get_code() {
                     401 | 404 => {
                         // try to authorize only if we are fetching the main /repos/foo/bar data, otherwise it must be a real 404
                         if !fetching_repo_data {
@@ -901,7 +895,9 @@ impl GitLabDriver {
                         self.inner.io.write_error3(
                             &format!(
                                 "<warning>Failed to download {}/{}:{}</warning>",
-                                self.namespace, self.repository, e.message
+                                self.namespace,
+                                self.repository,
+                                e.get_message()
                             ),
                             true,
                             io_interface::NORMAL,
@@ -1142,7 +1138,7 @@ impl crate::repository::vcs::VcsDriverInterface for GitLabDriver {
         match self.get_composer_information(identifier) {
             Ok(info) => Ok(info.is_some()),
             Err(e) => {
-                if e.downcast_ref::<TransportException>().is_some() {
+                if e.is_instanceof::<TransportException>() {
                     Ok(false)
                 } else {
                     Err(e)
diff --git a/crates/shirabe/src/repository/vcs/hg_driver.rs b/crates/shirabe/src/repository/vcs/hg_driver.rs
index 0283ed38..41aeebd9 100644
--- a/crates/shirabe/src/repository/vcs/hg_driver.rs
+++ b/crates/shirabe/src/repository/vcs/hg_driver.rs
@@ -12,6 +12,7 @@ use crate::util::Url;
 use chrono::{DateTime, FixedOffset, Utc};
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{PhpMixed, RuntimeException, dirname, is_dir, is_writable, php_regex};
 
 #[derive(Debug)]
@@ -53,10 +54,7 @@ impl HgDriver {
                 .unwrap_or("")
                 .to_string();
             if !Cache::is_usable(&cache_vcs_dir) {
-                return Err(RuntimeException {
-                    message: "HgDriver requires a usable cache directory, and it looks like you set it to be disabled".to_string(),
-                    code: 0,
-                }.into());
+                return Err(RuntimeException::new("HgDriver requires a usable cache directory, and it looks like you set it to be disabled".to_string()).into());
             }
 
             let sanitized = Preg::replace(
@@ -70,13 +68,10 @@ impl HgDriver {
             fs.ensure_directory_exists(&cache_vcs_dir)?;
 
             if !is_writable(dirname(&self.repo_dir)) {
-                return Err(RuntimeException {
-                    message: format!(
-                        "Can not clone {} to access package information. The \"{}\" directory is not writable by the current user.",
-                        self.inner.url, cache_vcs_dir
-                    ),
-                    code: 0,
-                }.into());
+                return Err(RuntimeException::new(format!(
+                    "Can not clone {} to access package information. The \"{}\" directory is not writable by the current user.",
+                    self.inner.url, cache_vcs_dir
+                )).into());
             }
 
             self.inner.config.borrow_mut().prohibit_url_by_config(
@@ -167,13 +162,10 @@ impl HgDriver {
 
     pub fn get_file_content(&self, file: &str, identifier: &str) -> anyhow::Result<Option<String>> {
         if identifier.starts_with('-') {
-            return Err(RuntimeException {
-                message: format!(
-                    "Invalid hg identifier detected. Identifier must not start with a -, given: {}",
-                    identifier
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Invalid hg identifier detected. Identifier must not start with a -, given: {}",
+                identifier
+            ))
             .into());
         }
 
@@ -203,13 +195,10 @@ impl HgDriver {
         identifier: &str,
     ) -> anyhow::Result<Option<DateTime<FixedOffset>>> {
         if identifier.starts_with('-') {
-            return Err(RuntimeException {
-                message: format!(
-                    "Invalid hg identifier detected. Identifier must not start with a -, given: {}",
-                    identifier
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "Invalid hg identifier detected. Identifier must not start with a -, given: {}",
+                identifier
+            ))
             .into());
         }
 
@@ -443,7 +432,7 @@ impl crate::repository::vcs::VcsDriverInterface for HgDriver {
         match self.get_composer_information(identifier) {
             Ok(info) => Ok(info.is_some()),
             Err(e) => {
-                if e.downcast_ref::<TransportException>().is_some() {
+                if e.is_instanceof::<TransportException>() {
                     Ok(false)
                 } else {
                     Err(e)
diff --git a/crates/shirabe/src/repository/vcs/perforce_driver.rs b/crates/shirabe/src/repository/vcs/perforce_driver.rs
index 452ac5a2..af16cd8c 100644
--- a/crates/shirabe/src/repository/vcs/perforce_driver.rs
+++ b/crates/shirabe/src/repository/vcs/perforce_driver.rs
@@ -79,10 +79,7 @@ impl PerforceDriver {
             .unwrap_or("")
             .to_string();
         if !Cache::is_usable(&cache_vcs_dir) {
-            return Err(RuntimeException {
-                message: "PerforceDriver requires a usable cache directory, and it looks like you set it to be disabled".to_string(),
-                code: 0,
-            }.into());
+            return Err(RuntimeException::new("PerforceDriver requires a usable cache directory, and it looks like you set it to be disabled".to_string()).into());
         }
 
         let repo_dir = format!("{}/{}", cache_vcs_dir, self.depot);
@@ -180,11 +177,10 @@ impl PerforceDriver {
     }
 
     pub fn get_contents(&self, _url: &str) -> anyhow::Result<Response> {
-        Err(BadMethodCallException {
-            message: "Not implemented/used in PerforceDriver".to_string(),
-            code: 0,
-        }
-        .into())
+        Err(
+            BadMethodCallException::new("Not implemented/used in PerforceDriver".to_string())
+                .into(),
+        )
     }
 
     pub fn supports(
diff --git a/crates/shirabe/src/repository/vcs/svn_driver.rs b/crates/shirabe/src/repository/vcs/svn_driver.rs
index 716b1943..84e3a20d 100644
--- a/crates/shirabe/src/repository/vcs/svn_driver.rs
+++ b/crates/shirabe/src/repository/vcs/svn_driver.rs
@@ -14,6 +14,7 @@ use crate::util::Url;
 use chrono::{DateTime, FixedOffset, Utc};
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     PhpMixed, RuntimeException, php_regex, stripos, strrpos, strtr, substr, trim,
 };
@@ -199,14 +200,14 @@ impl SvnDriver {
                 Ok(c) => c,
                 Err(e) => {
                     // PHP catches only TransportException; other exceptions propagate uncaught.
-                    if e.downcast_ref::<TransportException>().is_none() {
+                    if !e.is_instanceof::<TransportException>() {
                         return Err(e);
                     }
                     let message = e
-                        .downcast_ref::<TransportException>()
+                        .catch::<TransportException>()
                         .unwrap()
-                        .message
-                        .clone();
+                        .get_message()
+                        .to_string();
                     if stripos(&message, "path not found").is_none()
                         && stripos(&message, "svn: warning: W160013").is_none()
                     {
@@ -277,8 +278,8 @@ impl SvnDriver {
         ) {
             Ok(o) => o,
             Err(e) => {
-                if let Some(e) = e.downcast_ref::<RuntimeException>() {
-                    return Err(TransportException::new(e.message.clone(), 0).into());
+                if let Some(e) = e.catch::<RuntimeException>() {
+                    return Err(TransportException::new(e.get_message().to_string(), 0).into());
                 }
                 return Err(e);
             }
@@ -567,24 +568,18 @@ impl SvnDriver {
             Ok(o) => Ok(o),
             Err(e) => {
                 if self.util.as_mut().unwrap().binary_version().is_none() {
-                    return Err(RuntimeException {
-                        message: format!(
-                            "Failed to load {}, svn was not found, check that it is installed and in your PATH env.\n\n{}",
-                            self.inner.url,
-                            self.inner.process.borrow().get_error_output(),
-                        ),
-                        code: 0,
-                    }
+                    return Err(RuntimeException::new(format!(
+                        "Failed to load {}, svn was not found, check that it is installed and in your PATH env.\n\n{}",
+                        self.inner.url,
+                        self.inner.process.borrow().get_error_output(),
+                    ))
                     .into());
                 }
 
-                Err(RuntimeException {
-                    message: format!(
-                        "Repository {} could not be processed, {}",
-                        self.inner.url, e,
-                    ),
-                    code: 0,
-                }
+                Err(RuntimeException::new(format!(
+                    "Repository {} could not be processed, {}",
+                    self.inner.url, e,
+                ))
                 .into())
             }
         }
@@ -655,7 +650,7 @@ impl crate::repository::vcs::VcsDriverInterface for SvnDriver {
         match self.get_composer_information(identifier) {
             Ok(info) => Ok(info.is_some()),
             Err(e) => {
-                if e.downcast_ref::<TransportException>().is_some() {
+                if e.is_instanceof::<TransportException>() {
                     Ok(false)
                 } else {
                     Err(e)
diff --git a/crates/shirabe/src/repository/vcs/vcs_driver.rs b/crates/shirabe/src/repository/vcs/vcs_driver.rs
index 3321201c..42f679df 100644
--- a/crates/shirabe/src/repository/vcs/vcs_driver.rs
+++ b/crates/shirabe/src/repository/vcs/vcs_driver.rs
@@ -13,6 +13,7 @@ use crate::util::http::Response;
 use chrono::{DateTime, FixedOffset};
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::Preg;
+use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{DATE_RFC3339, PhpMixed, extension_loaded, php_regex};
 
 #[derive(Debug)]
@@ -66,7 +67,7 @@ impl VcsDriverBase {
         "http"
     }
 
-    pub fn get_contents(&self, url: &str) -> anyhow::Result<Response, TransportException> {
+    pub fn get_contents(&self, url: &str) -> anyhow::Result<Response, Box<TransportException>> {
         let options_mixed = self
             .repo_config
             .get("options")
@@ -79,9 +80,11 @@ impl VcsDriverBase {
         self.http_downloader
             .borrow_mut()
             .get(url, options)
-            .map_err(|e| match e.downcast::<TransportException>() {
-                Ok(te) => te,
-                Err(other) => TransportException::new(other.to_string(), 0),
+            .map_err(|e| {
+                Box::new(match e.catch::<TransportException>() {
+                    Some(te) => te.clone(),
+                    None => TransportException::new(e.to_string(), 0),
+                })
             })
     }
 
@@ -299,7 +302,7 @@ pub trait VcsDriver: VcsDriverInterface {
         "http"
     }
 
-    fn get_contents(&self, url: &str) -> anyhow::Result<Response, TransportException> {
+    fn get_contents(&self, url: &str) -> anyhow::Result<Response, Box<TransportException>> {
         let options_mixed = self
             .repo_config()
             .get("options")
@@ -312,9 +315,11 @@ pub trait VcsDriver: VcsDriverInterface {
         self.http_downloader()
             .borrow_mut()
             .get(url, options)
-            .map_err(|e| match e.downcast::<TransportException>() {
-                Ok(te) => te,
-                Err(other) => TransportException::new(other.to_string(), 0),
+            .map_err(|e| {
+                Box::new(match e.catch::<TransportException>() {
+                    Some(te) => te.clone(),
+                    None => TransportException::new(e.to_string(), 0),
+                })
             })
     }