repo: make all base_repo() functions return &Arc<ReadonlyRepo>

This is to prepare for a `Repo` trait implemented for
`Arc<ReadonlyRepo>` (not for `ReadonlyRepo` itself).

lib/src/repo.rs

@@ -53,15 +53,15 @@ use crate::{backend, op_store};
 // RepoRef?
 #[derive(Clone, Copy)]
 pub enum RepoRef<'a> {
-    Readonly(&'a ReadonlyRepo),
+    Readonly(&'a Arc<ReadonlyRepo>),
     Mutable(&'a MutableRepo),
 }
 
 impl<'a> RepoRef<'a> {
-    pub fn base_repo(&self) -> &ReadonlyRepo {
+    pub fn base_repo(&self) -> &Arc<ReadonlyRepo> {
         match self {
-            RepoRef::Readonly(repo) => repo,
-            RepoRef::Mutable(repo) => repo.base_repo.as_ref(),
+            RepoRef::Readonly(repo) => &repo,
+            RepoRef::Mutable(repo) => &repo.base_repo,
         }
     }
 
@@ -245,7 +245,7 @@ impl ReadonlyRepo {
         }
     }
 
-    pub fn as_repo_ref(&self) -> RepoRef {
+    pub fn as_repo_ref<'a>(self: &'a Arc<Self>) -> RepoRef<'a> {
         RepoRef::Readonly(self)
     }
 

lib/src/transaction.rs

@@ -48,7 +48,7 @@ impl Transaction {
         }
     }
 
-    pub fn base_repo(&self) -> &ReadonlyRepo {
+    pub fn base_repo(&self) -> &Arc<ReadonlyRepo> {
         self.mut_repo.base_repo()
     }
 

src/cli_util.rs

@@ -1017,7 +1017,7 @@ impl WorkspaceCommandTransaction<'_> {
         self.helper
     }
 
-    pub fn base_repo(&self) -> &ReadonlyRepo {
+    pub fn base_repo(&self) -> &Arc<ReadonlyRepo> {
         self.tx.base_repo()
     }