git-linguist: Do not write cache if repo is gone

bin/git-linguist

@@ -71,17 +71,20 @@ class GitLinguist
   end
 
   def write_cache(object)
-    tmp_path = Dir::Tmpname.make_tmpname(cache_file, nil)
+    return unless File.directory? @repo_path
 
-    File.open(tmp_path, "wb") do |f|
-      marshal = Marshal.dump(object)
-      f.write(Zlib::Deflate.deflate(marshal))
+    begin
+      tmp_path = Dir::Tmpname.make_tmpname(cache_file, nil)
+      File.open(tmp_path, "wb") do |f|
+        marshal = Marshal.dump(object)
+        f.write(Zlib::Deflate.deflate(marshal))
+      end
+
+      File.rename(tmp_path, cache_file)
+    rescue => e
+      (File.unlink(tmp_path) rescue nil)
+      raise e
     end
-
-    File.rename(tmp_path, cache_file)
-    tmp_path = nil
-  ensure
-    (File.unlink(tmp_path) rescue nil) if tmp_path
   end
 
   def load_cache