Show launch failure reason in the splash

autoload/vimspector/internal/neopopup.vim

@@ -26,24 +26,39 @@ set cpoptions&vim
 let s:db = {}
 let s:next_id = 0
 
+
+function! s:MessageToList( message ) abort
+  if type( a:message ) == type( [] )
+    let message = a:message
+  else
+    let message = [ a:message ]
+  endif
+  return message
+endfunction
+
+function! s:GetSplashConfig( message ) abort
+  let l = max( map( a:message, 'len( v:val )' ) )
+  let h = len( a:message )
+
+  return { 'relative':   'editor',
+         \ 'width':      l,
+         \ 'height':     h,
+         \ 'col':        ( &columns / 2 ) - ( l / 2 ),
+         \ 'row':        ( &lines / 2 ) - h / 2,
+         \ 'anchor':     'NW',
+         \ 'style':      'minimal',
+         \ 'focusable':  v:false,
+         \ }
+endfunction
+
 function! vimspector#internal#neopopup#DisplaySplash( message ) abort
+  let message = s:MessageToList( a:message )
   let buf = nvim_create_buf(v:false, v:true)
-  call nvim_buf_set_lines(buf, 0, -1, v:true, [ a:message ] )
+  call nvim_buf_set_lines(buf, 0, -1, v:true, message )
 
-  let l = len( a:message )
-
-  let opts = {
-        \ 'relative':   'editor',
-        \ 'width':      l,
-        \ 'height':     1,
-        \ 'col':        ( &columns / 2 ) - ( l / 2 ),
-        \ 'row':        &lines / 2,
-        \ 'anchor':     'NW',
-        \ 'style':      'minimal',
-        \ 'focusable':  v:false,
-        \ }
-  let win = nvim_open_win(buf, 0, opts)
+  let win = nvim_open_win(buf, 0, s:GetSplashConfig( message ) )
   call nvim_win_set_option(win, 'wrap', v:false)
+  call nvim_win_set_option(win, 'colorcolumn', '')
 
   let id = s:next_id
   let s:next_id += 1
@@ -53,7 +68,9 @@ endfunction
 
 function! vimspector#internal#neopopup#UpdateSplash( id, message ) abort
   let splash = s:db[ a:id ]
-  call nvim_buf_set_lines(splash.buf, 0, -1, v:true, [ a:message ] )
+  let message = s:MessageToList( a:message )
+  call nvim_buf_set_lines( splash.buf, 0, -1, v:true, message )
+  call nvim_win_set_config( splash.win, s:GetSplashConfig( message ) )
   return a:id
 endfunction
 

python3/vimspector/debug_session.py

@@ -940,13 +940,26 @@ class DebugSession( object ):
     if 'name' not in launch_config:
       launch_config[ 'name' ] = 'test'
 
+    def failure_handler( reason, msg ):
+      text = [
+        'Launch Failed',
+        '',
+        reason,
+        '',
+        'Use :VimspectorReset to close'
+      ]
+      self._splash_screen = utils.DisplaySplash( self._api_prefix,
+                                                 self._splash_screen,
+                                                 text )
+
+
     self._connection.DoRequest(
       lambda msg: self._OnLaunchComplete(),
       {
         'command': launch_config[ 'request' ],
         'arguments': launch_config
-      }
-    )
+      },
+      failure_handler )
 
 
   def _OnLaunchComplete( self ):