feat(vcs): add mozart-vcs crate for VCS repository support

Implement VCS driver/downloader infrastructure mirroring Composer's VCS
subsystem. Includes drivers for GitHub, GitLab, Bitbucket, Forgejo, Git,
Hg, and SVN with API-based metadata resolution, plus source downloaders
for Git/Hg/SVN. Integrates into mozart-registry via vcs_bridge module to
scan VCS repositories and feed discovered packages into the SAT resolver.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/crates/mozart-vcs/src/downloader/svn.rs b/crates/mozart-vcs/src/downloader/svn.rs
new file mode 100644
index 0000000..5222b06
--- /dev/null
+++ b/crates/mozart-vcs/src/downloader/svn.rs
@@ -0,0 +1,64 @@
+use std::path::Path;
+
+use anyhow::Result;
+
+use crate::util::svn::SvnUtil;
+
+use super::VcsDownloader;
+
+/// SVN downloader using checkout/switch.
+pub struct SvnDownloader {
+    svn_util: SvnUtil,
+}
+
+impl SvnDownloader {
+    pub fn new(svn_util: SvnUtil) -> Self {
+        Self { svn_util }
+    }
+}
+
+impl VcsDownloader for SvnDownloader {
+    fn download(&self, _url: &str, _reference: &str, _target: &Path) -> Result<()> {
+        // SVN doesn't need a pre-download step
+        Ok(())
+    }
+
+    fn install(&self, url: &str, reference: &str, target: &Path) -> Result<()> {
+        let target_str = target.to_string_lossy().to_string();
+        let svn_url = format!("{url}@{reference}");
+        self.svn_util
+            .execute(&["checkout", &svn_url, &target_str], None)?;
+        Ok(())
+    }
+
+    fn update(&self, url: &str, _old_ref: &str, new_ref: &str, target: &Path) -> Result<()> {
+        let svn_url = format!("{url}@{new_ref}");
+        self.svn_util
+            .execute(&["switch", "--ignore-ancestry", &svn_url], Some(target))?;
+        Ok(())
+    }
+
+    fn remove(&self, target: &Path) -> Result<()> {
+        if target.exists() {
+            std::fs::remove_dir_all(target)?;
+        }
+        Ok(())
+    }
+
+    fn local_changes(&self, target: &Path) -> Result<Option<String>> {
+        let output = self.svn_util.execute(&["status"], Some(target))?;
+        if output.stdout.trim().is_empty() {
+            Ok(None)
+        } else {
+            Ok(Some(output.stdout))
+        }
+    }
+
+    fn commit_logs(&self, from: &str, to: &str, target: &Path) -> Result<String> {
+        let range = format!("{from}:{to}");
+        let output = self
+            .svn_util
+            .execute(&["log", "-r", &range], Some(target))?;
+        Ok(output.stdout)
+    }
+}