Don't migrate from the old database if it doesn't exist

src/repo.rs

@@ -243,10 +243,9 @@ impl Repo {
             return Ok(());
         }
 
+        if let Some(old) = self::old::Old::open(path)? {
             tracing::warn!("Migrating Database from 0.3 layout to 0.4 layout");
 
-        let old = self::old::Old::open(path)?;
-
             for hash in old.hashes() {
                 match self {
                     Self::Sled(repo) => {
@@ -256,6 +255,7 @@ impl Repo {
                     }
                 }
             }
+        }
 
         self.mark_migrated().await?;
 

src/repo/old.rs

@@ -44,10 +44,9 @@ pub(super) struct Old {
 }
 
 impl Old {
-    pub(super) fn open(path: PathBuf) -> color_eyre::Result<Self> {
-        let db = migrate::LatestDb::exists(path).migrate()?;
-
-        Ok(Self {
+    pub(super) fn open(path: PathBuf) -> color_eyre::Result<Option<Self>> {
+        if let Some(db) = migrate::LatestDb::exists(path).migrate()? {
+            Ok(Some(Self {
                 alias_tree: db.open_tree("alias")?,
                 filename_tree: db.open_tree("filename")?,
                 main_tree: db.open_tree("main")?,
@@ -55,7 +54,10 @@ impl Old {
                 settings_tree: db.open_tree("settings")?,
                 identifier_tree: db.open_tree("path")?,
                 _db: db,
-        })
+            }))
+        } else {
+            Ok(None)
+        }
     }
 
     pub(super) fn setting(&self, key: &[u8]) -> color_eyre::Result<Option<sled::IVec>> {

src/repo/old/migrate.rs

@@ -60,7 +60,7 @@ impl LatestDb {
         LatestDb { root_dir, version }
     }
 
-    pub(crate) fn migrate(self) -> Result<sled::Db, Error> {
+    pub(crate) fn migrate(self) -> Result<Option<sled::Db>, Error> {
         let LatestDb { root_dir, version } = self;
 
         loop {
@@ -89,9 +89,10 @@ impl DbVersion {
         DbVersion::Fresh
     }
 
-    fn migrate(self, root: PathBuf) -> Result<sled::Db, Error> {
+    fn migrate(self, root: PathBuf) -> Result<Option<sled::Db>, Error> {
         match self {
-            DbVersion::Sled034 | DbVersion::Fresh => s034::open(root),
+            DbVersion::Sled034 => Some(s034::open(root)).transpose(),
+            DbVersion::Fresh => Ok(None),
         }
     }
 }