refactor(downloader): take &self across the downloader hierarchy

Concurrent package operations call into the same downloader instances
through Rc<RefCell<dyn DownloaderInterface>>; with &mut self methods
every call holds a RefMut across its awaits, which panics with
'already mutably borrowed' the moment two operations overlap. This is
groundwork for fanning out InstallationManager's download/install
loops (same rework HttpDownloader/CurlDownloader already got).

- DownloaderInterface/ChangeReportInterface/ArchiveDownloader/
  VcsDownloader methods now take &self; as_change_report_interface
  returns &dyn instead of &mut dyn.
- Implementors move their genuinely mutable state behind cells:
  FileDownloader.additional_cleanup_paths, the archive downloaders'
  cleanup_executed, ZipDownloader.zip_archive_object,
  VcsDownloaderBase.has_cleaned_changes, GitDownloader's stash/discard/
  cache maps and GitUtil, SvnDownloader.cache_credentials,
  PerforceDownloader.perforce. FileDownloader.io gains a RefCell layer
  so get_local_changes can keep PHP's NullIO swap under &self.
- ProcessExecutor::execute_async now returns a future that captures
  everything up front instead of borrowing the executor, and call
  sites build the future before awaiting, so no borrow on the shared
  executor is held while a subprocess runs.
- Filesystem::remove_directory_async becomes remove_directory_async_via
  taking the Rc handle: the Filesystem is only borrowed for the sync
  head/tail, never across the rm subprocess await (sync borrow_mut
  users like rename/ensure_directory_exists would otherwise collide).
- DownloadManager async call sites hold shared borrows only.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

1 files changed, 13 insertions, 13 deletions

diff --git a/crates/shirabe/tests/downloader/git_downloader_test.rs b/crates/shirabe/tests/downloader/git_downloader_test.rs
index d4f40b77..f7c82066 100644
--- a/crates/shirabe/tests/downloader/git_downloader_test.rs
+++ b/crates/shirabe/tests/downloader/git_downloader_test.rs
@@ -120,7 +120,7 @@ fn test_download_for_package_without_source_reference() {
     let package = get_package("dummy/pkg", "1.0.0", None, None);
 
     let (process, _guard) = get_process_executor_mock(vec![], false, Default::default());
-    let mut downloader = get_downloader_mock(None, None, process, None);
+    let downloader = get_downloader_mock(None, None, process, None);
 
     let result = run(async {
         downloader.download(package.clone(), "/path", None).await?;
@@ -183,7 +183,7 @@ fn test_download() {
         Default::default(),
     );
 
-    let mut downloader = get_downloader_mock(None, None, process, None);
+    let downloader = get_downloader_mock(None, None, process, None);
 
     run(async {
         downloader
@@ -303,7 +303,7 @@ fn test_download_with_cache() {
         Default::default(),
     );
 
-    let mut downloader = get_downloader_mock(None, Some(config), process, None);
+    let downloader = get_downloader_mock(None, Some(config), process, None);
 
     run(async {
         downloader
@@ -428,7 +428,7 @@ fn test_download_uses_various_protocols_and_sets_push_url_for_github() {
         Default::default(),
     );
 
-    let mut downloader = get_downloader_mock(None, None, process, None);
+    let downloader = get_downloader_mock(None, None, process, None);
 
     run(async {
         downloader
@@ -529,7 +529,7 @@ fn test_download_and_set_push_url_use_custom_various_protocols_for_github() {
         top.insert("config".to_string(), PhpMixed::Array(section));
         config.merge(&top, Config::SOURCE_UNKNOWN);
 
-        let mut downloader = get_downloader_mock(None, Some(config), process, None);
+        let downloader = get_downloader_mock(None, Some(config), process, None);
 
         run(async {
             downloader
@@ -578,7 +578,7 @@ fn test_download_throws_runtime_exception_if_git_command_fails() {
         Default::default(),
     );
 
-    let mut downloader = get_downloader_mock(None, None, process, None);
+    let downloader = get_downloader_mock(None, None, process, None);
 
     let result = run(async {
         downloader
@@ -610,7 +610,7 @@ fn test_updatefor_package_without_source_reference() {
     let source_package = get_package("dummy/pkg", "1.0.0", None, None);
 
     let (process, _guard) = get_process_executor_mock(vec![], false, Default::default());
-    let mut downloader = get_downloader_mock(None, None, process, None);
+    let downloader = get_downloader_mock(None, None, process, None);
 
     let result = run(async {
         downloader
@@ -680,7 +680,7 @@ fn test_update() {
         .unwrap();
     let working_dir_str = working_dir.path().to_string_lossy().into_owned();
 
-    let mut downloader = get_downloader_mock(None, Some(Config::new(false, None)), process, None);
+    let downloader = get_downloader_mock(None, Some(Config::new(false, None)), process, None);
 
     run(async {
         downloader
@@ -760,7 +760,7 @@ fn test_update_with_new_repo_url() {
         .unwrap();
     let working_dir_str = working_dir.path().to_string_lossy().into_owned();
 
-    let mut downloader = get_downloader_mock(None, Some(Config::new(false, None)), process, None);
+    let downloader = get_downloader_mock(None, Some(Config::new(false, None)), process, None);
 
     run(async {
         downloader
@@ -842,7 +842,7 @@ fn test_update_throws_runtime_exception_if_git_command_fails() {
 
     let config = Config::new(false, None);
 
-    let mut downloader = get_downloader_mock(None, Some(config), process, None);
+    let downloader = get_downloader_mock(None, Some(config), process, None);
 
     let result = run(async {
         downloader
@@ -945,7 +945,7 @@ fn test_update_doesnt_throws_runtime_exception_if_git_command_fails_at_first_but
         .unwrap();
     let working_dir_str = working_dir.path().to_string_lossy().into_owned();
 
-    let mut downloader = get_downloader_mock(None, Some(Config::new(false, None)), process, None);
+    let downloader = get_downloader_mock(None, Some(Config::new(false, None)), process, None);
 
     run(async {
         downloader
@@ -1001,7 +1001,7 @@ fn test_downgrade_shows_appropriate_message() {
         .unwrap();
     let working_dir_str = working_dir.path().to_string_lossy().into_owned();
 
-    let mut downloader = get_downloader_mock(Some(io), None, process, None);
+    let downloader = get_downloader_mock(Some(io), None, process, None);
 
     run(async {
         downloader
@@ -1079,7 +1079,7 @@ fn test_not_using_downgrading_with_references() {
         .unwrap();
     let working_dir_str = working_dir.path().to_string_lossy().into_owned();
 
-    let mut downloader = get_downloader_mock(Some(io), None, process, None);
+    let downloader = get_downloader_mock(Some(io), None, process, None);
 
     run(async {
         downloader