fix(config,loader): wire JsonValidationException catch; drop unportable chain TODOs

JsonConfigSource::manipulate_json now downcasts the validate_schema error
to JsonValidationException (matching PHP's specific catch), restores the
original contents, and surfaces e.get_errors(); other errors propagate.

ArrayLoader's two version-parse catch sites only had TODOs for preserving
the original exception as 'previous'. shirabe_semver raises generic
anyhow errors (not shim exception types), so the existing catch-all is
already faithful to PHP's catch (\UnexpectedValueException), and the flat
shim exception structs intentionally hold no previous field; the wrapped
message already carries the original cause. Remove the stale TODOs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

2 files changed, 5 insertions, 8 deletions

diff --git a/crates/shirabe/src/config/json_config_source.rs b/crates/shirabe/src/config/json_config_source.rs
index 7b5fc03..28481db 100644
--- a/crates/shirabe/src/config/json_config_source.rs
+++ b/crates/shirabe/src/config/json_config_source.rs
@@ -207,19 +207,19 @@ impl JsonConfigSource {
             )?;
         }
 
-        // TODO(phase-b): use anyhow::Result<Result<T, E>> to model PHP try/catch
         match self.file.validate_schema(JsonFile::LAX_SCHEMA, None) {
             Ok(_) => {}
             Err(e) => {
-                // TODO(phase-b): downcast e to JsonValidationException to match the specific catch
-                let _jve: &JsonValidationException = todo!("downcast e to JsonValidationException");
+                let Some(jve) = e.downcast_ref::<JsonValidationException>() else {
+                    return Err(e);
+                };
                 // restore contents to the original state
                 file_put_contents(self.file.get_path(), contents.as_bytes());
                 return Err(RuntimeException {
                     message: format!(
                         "Failed to update composer.json with a valid format, reverting to the original content. Please report an issue to us with details (command you run and a copy of your composer.json). {}{}",
                         PHP_EOL,
-                        implode(PHP_EOL, todo!("e.get_errors()")),
+                        implode(PHP_EOL, jve.get_errors()),
                     ),
                     code: 0,
                 }
diff --git a/crates/shirabe/src/package/loader/array_loader.rs b/crates/shirabe/src/package/loader/array_loader.rs
index e1cc60b..634bef8 100644
--- a/crates/shirabe/src/package/loader/array_loader.rs
+++ b/crates/shirabe/src/package/loader/array_loader.rs
@@ -195,7 +195,6 @@ impl ArrayLoader {
             {
                 Ok(v) => version = v,
                 Err(e) => {
-                    // TODO(phase-b): preserve original exception chain via anyhow::Error::context
                     return Err(UnexpectedValueException {
                         message: format!(
                             "Failed to normalize version for package \"{}\": {}",
@@ -761,9 +760,7 @@ impl ArrayLoader {
 
         let parsed_constraint = match self.version_parser.parse_constraints(&constraint) {
             Ok(c) => c,
-            Err(e) => {
-                // TODO(phase-b): preserve original exception chain
-                let _ = &e;
+            Err(_e) => {
                 return Err(UnexpectedValueException {
                     message: format!(
                         "Link constraint in {} {} > {} should be a valid version constraint, got \"{}\"",