Let the callback also handle the error itself

- Also fix an unwrap in Rust.

Close #500

autoload/clap/client.vim

@@ -16,14 +16,8 @@ function! clap#client#handle(msg) abort
     return
   endif
 
-  if has_key(decoded, 'error')
-    " TODO: show the error message in preview window when it's on_move
-    call clap#helper#echo_error('[client_handle] '.string(decoded.error))
-    return
-  endif
-
   if has_key(s:handlers, decoded.id)
-    call s:handlers[decoded.id](decoded.result)
+    call s:handlers[decoded.id](get(decoded, 'result', v:null), get(decoded, 'error', v:null))
     call remove(s:handlers, decoded.id)
     return
   endif

autoload/clap/impl/on_move.vim

@@ -18,7 +18,10 @@ if clap#maple#is_available()
 
   let s:async_preview_implemented = ['files', 'git_files', 'grep', 'grep2', 'proj_tags', 'tags', 'blines', 'history']
 
-  function! s:handle_on_move_result(result) abort
+  function! s:handle_on_move_result(result, error) abort
+    if a:error isnot v:null
+      return
+    endif
     if has_key(a:result, 'lines')
       try
         call g:clap.preview.show(a:result.lines)

autoload/clap/provider/commits.vim

@@ -55,7 +55,10 @@ function! s:commits.on_move() abort
   call clap#provider#commits#on_move_common('git show '.rev)
 endfunction
 
-function! clap#provider#commits#on_move_callback(result) abort
+function! clap#provider#commits#on_move_callback(result, error) abort
+  if a:error isnot v:null
+    return
+  endif
   let lines = a:result.lines
   call clap#preview#show_lines(lines, 'diff', -1)
   call clap#preview#highlight_header()

autoload/clap/provider/filer.vim

@@ -15,7 +15,17 @@ function! clap#provider#filer#hi_empty_dir() abort
   hi default link ClapEmptyDirectory WarningMsg
 endfunction
 
-function! s:handle_result(result) abort
+function! s:handle_error(error) abort
+  let s:filer_error_cache[a:error.dir] = a:error.message
+  call g:clap.display.set_lines([a:error.message])
+  call clap#indicator#set('[??]')
+endfunction
+
+function! s:handle_result(result, error) abort
+  if a:error isnot v:null
+    call s:handle_error(a:error)
+    return
+  endif
   if a:result.total == 0
     let s:filer_empty_cache[a:result.dir] = s:DIRECTORY_IS_EMPTY
     call g:clap.display.set_lines([s:DIRECTORY_IS_EMPTY])
@@ -30,10 +40,7 @@ endfunction
 
 function! clap#provider#filer#daemon_handle(decoded) abort
   if has_key(a:decoded, 'error')
-    let error = a:decoded.error
-    let s:filer_error_cache[error.dir] = error.message
-    call g:clap.display.set_lines([error.message])
-    call clap#indicator#set('[??]')
+    call s:handle_error(a:decoded.error)
     return
   endif
 
@@ -226,7 +233,12 @@ function! s:sync_on_move_impl() abort
   endif
 endfunction
 
-function! s:filer_handle_on_move_result(result) abort
+function! s:filer_handle_on_move_result(result, error) abort
+  if a:error isnot v:null
+    call s:handle_error(a:error)
+    return
+  endif
+
   if empty(a:result.lines)
     call g:clap.preview.show(['Empty entries'])
   else

crates/stdio_server/src/filer.rs

@@ -91,7 +91,11 @@ impl HandleMessage for FilerMessageHandler {
                     context,
                     inner: OnMove::Filer(path),
                 };
-                on_move_handler.handle().unwrap();
+                if let Err(err) = on_move_handler.handle() {
+                    let error = json!({"message": format!("{}", err), "dir": msg.get_cwd()});
+                    let res = json!({ "id": msg.id, "provider_id": "filer", "error": error });
+                    write_response(res);
+                }
             }
             // TODO: handle on_typed
             RpcMessage::OnTyped(msg) => handle_message(msg),