feat(downloader): return Result from getUnpushedChanges to bubble RuntimeException

Match PHP GitDownloader::getUnpushedChanges, which returns ?string while
throwing \RuntimeException on git command failure. Change the signature to
Result<Option<String>> and replace the three panic\!() sites with
Err(RuntimeException), mirroring the get_local_changes port. Thread ? through
the clean_changes and StatusCommand call sites.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

3 files changed, 33 insertions, 28 deletions

diff --git a/crates/shirabe/src/command/status_command.rs b/crates/shirabe/src/command/status_command.rs
index dba4cc8..01c1b5e 100644
--- a/crates/shirabe/src/command/status_command.rs
+++ b/crates/shirabe/src/command/status_command.rs
@@ -199,7 +199,7 @@ impl StatusCommand {
 
             if let Some(dvcs_downloader) = downloader.as_dvcs_downloader_interface() {
                 if let Some(unpushed) =
-                    dvcs_downloader.get_unpushed_changes(package.clone(), target_dir.clone())
+                    dvcs_downloader.get_unpushed_changes(package.clone(), target_dir.clone())?
                 {
                     unpushed_changes.insert(target_dir, unpushed);
                 }
diff --git a/crates/shirabe/src/downloader/dvcs_downloader_interface.rs b/crates/shirabe/src/downloader/dvcs_downloader_interface.rs
index 4c8ebd3..59f5774 100644
--- a/crates/shirabe/src/downloader/dvcs_downloader_interface.rs
+++ b/crates/shirabe/src/downloader/dvcs_downloader_interface.rs
@@ -1,8 +1,13 @@
 //! ref: composer/src/Composer/Downloader/DvcsDownloaderInterface.php
 
+use anyhow::Result;
+
 use crate::package::PackageInterfaceHandle;
 
 pub trait DvcsDownloaderInterface {
-    fn get_unpushed_changes(&self, package: PackageInterfaceHandle, path: String)
-    -> Option<String>;
+    fn get_unpushed_changes(
+        &self,
+        package: PackageInterfaceHandle,
+        path: String,
+    ) -> Result<Option<String>>;
 }
diff --git a/crates/shirabe/src/downloader/git_downloader.rs b/crates/shirabe/src/downloader/git_downloader.rs
index acf935b..05ef096 100644
--- a/crates/shirabe/src/downloader/git_downloader.rs
+++ b/crates/shirabe/src/downloader/git_downloader.rs
@@ -461,11 +461,11 @@ impl GitDownloader {
         &self,
         _package: PackageInterfaceHandle,
         path: &str,
-    ) -> Option<String> {
+    ) -> Result<Option<String>> {
         GitUtil::clean_env(&self.inner.process);
         let path = self.normalize_path(path);
         if !self.has_metadata_repository(&path) {
-            return None;
+            return Ok(None);
         }
 
         let command = vec![
@@ -482,15 +482,15 @@ impl GitDownloader {
             .execute_args(&command, &mut output, Some(path.clone()))
             != 0
         {
-            // TODO(phase-b): bubble error via Result later
-            panic!(
-                "{}",
-                format!(
+            return Err(RuntimeException {
+                message: format!(
                     "Failed to execute {}\n\n{}",
                     implode(" ", &command),
                     self.inner.process.borrow().get_error_output(),
-                )
-            );
+                ),
+                code: 0,
+            }
+            .into());
         }
 
         let mut refs = trim(&output, None);
@@ -499,7 +499,7 @@ impl GitDownloader {
             .unwrap_or(false)
         {
             // could not match the HEAD for some reason
-            return None;
+            return Ok(None);
         }
         let head_ref = head_match
             .get(&CaptureKey::ByIndex(1))
@@ -515,7 +515,7 @@ impl GitDownloader {
         .unwrap_or(false)
         {
             // not on a branch, we are either on a not-modified tag or some sort of detached head, so skip this
-            return None;
+            return Ok(None);
         }
         let candidate_branches: Vec<String> = branches_match
             .get(&CaptureKey::ByIndex(1))
@@ -584,15 +584,15 @@ impl GitDownloader {
                         Some(path.clone()),
                     ) != 0
                     {
-                        // TODO(phase-b): bubble error via Result later
-                        panic!(
-                            "{}",
-                            format!(
+                        return Err(RuntimeException {
+                            message: format!(
                                 "Failed to execute {}\n\n{}",
                                 implode(" ", &command),
                                 self.inner.process.borrow().get_error_output(),
-                            )
-                        );
+                            ),
+                            code: 0,
+                        }
+                        .into());
                     }
 
                     let output = trim(&output, None);
@@ -629,15 +629,15 @@ impl GitDownloader {
                     Some(path.clone()),
                 ) != 0
                 {
-                    // TODO(phase-b): bubble error via Result later
-                    panic!(
-                        "{}",
-                        format!(
+                    return Err(RuntimeException {
+                        message: format!(
                             "Failed to execute {}\n\n{}",
                             implode(" ", &command),
                             self.inner.process.borrow().get_error_output(),
-                        )
-                    );
+                        ),
+                        code: 0,
+                    }
+                    .into());
                 }
                 refs = trim(&output, None);
             }
@@ -648,7 +648,7 @@ impl GitDownloader {
             }
         }
 
-        unpushed_changes
+        Ok(unpushed_changes)
     }
 
     pub(crate) async fn clean_changes(
@@ -660,7 +660,7 @@ impl GitDownloader {
         GitUtil::clean_env(&self.inner.process);
         let path = self.normalize_path(path);
 
-        let unpushed = self.get_unpushed_changes(package.clone(), &path);
+        let unpushed = self.get_unpushed_changes(package.clone(), &path)?;
         if let Some(unpushed) = unpushed.as_deref() {
             if self.inner.io.is_interactive()
                 || self
@@ -1325,7 +1325,7 @@ impl DvcsDownloaderInterface for GitDownloader {
         &self,
         package: PackageInterfaceHandle,
         path: String,
-    ) -> Option<String> {
+    ) -> Result<Option<String>> {
         GitDownloader::get_unpushed_changes(self, package, &path)
     }
 }