make relative links when the canonical and new db paths are in the same directory

blockstore/badger/blockstore.go

@@ -355,7 +355,7 @@ func (b *Blockstore) movingGC() error {
 		panic(fmt.Errorf("error renaming old badger db dir from %s to %s: %w; USER ACTION REQUIRED", dbPath, backupPath, err)) //nolint
 	}
 
-	if err = os.Symlink(newPath, dbPath); err != nil {
+	if err = b.symlink(newPath, dbPath); err != nil {
 		// same here; the db path is pointing to the void. panic and let the user fix.
 		panic(fmt.Errorf("error symlinking new badger db dir from %s to %s: %w; USER ACTION REQUIRED", newPath, dbPath, err)) //nolint
 	}
@@ -367,6 +367,18 @@ func (b *Blockstore) movingGC() error {
 	return nil
 }
 
+// symlink creates a symlink from path to linkPath; the link is relative if the two are
+// in the same directory
+func (b *Blockstore) symlink(path, linkTo string) error {
+	pathDir := filepath.Dir(path)
+	linkDir := filepath.Dir(linkTo)
+	if pathDir == linkDir {
+		path = filepath.Base(path)
+	}
+
+	return os.Symlink(path, linkTo)
+}
+
 // doCopy copies a badger blockstore to another, with an optional filter; if the filter
 // is not nil, then only cids that satisfy the filter will be copied.
 func (b *Blockstore) doCopy(from, to *badger.DB) error {