Handle writes to closed language-server pipes

A language server can exit and close its communication pipe before
vis-lspc sends its next RPC message. The resulting Lua file-handle error
escapes the RPC function and interrupts editing. Catch failures from write
and flush, log the server name and error, and return false instead.

1 files changed, 9 insertions, 2 deletions

diff --git a/init.lua b/init.lua
index 447b9bb..383d599 100644
--- a/init.lua
+++ b/init.lua
@@ -668,8 +668,15 @@ function LanguageServer:rpc(req)
   local msg = header_part .. '\r\n\r\n' .. content_part
   lspc:log('LSPC Sending -> ' .. self.name .. ': ' .. msg)
 
-  self.fd:write(msg)
-  self.fd:flush()
+  local ok, err = pcall(function()
+    self.fd:write(msg)
+    self.fd:flush()
+  end)
+  if not ok then
+    lspc:warn('Could not send message to ' .. self.name .. ': ' .. tostring(err))
+    return false
+  end
+  return true
 end
 
 --- Send a RPC notification to the language server