buffer: fix index defect in updateHover

Caused by a race condition when updateHover is executed after
buffer.lines.len changed in buffer but before the change has been
reported to container.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/server/buffer.nim b/src/server/buffer.nim
index cbefc5a2..e5cdf50d 100644
--- a/src/server/buffer.nim
+++ b/src/server/buffer.nim
@@ -661,7 +661,8 @@ type UpdateHoverResult* = object
   repaint*: bool
 
 proc updateHover*(buffer: Buffer, cursorx, cursory: int): UpdateHoverResult {.proxy.} =
-  if buffer.lines.len == 0: return
+  if cursory >= buffer.lines.len:
+    return
   var thisnode: StyledNode
   let i = buffer.lines[cursory].findFormatN(cursorx) - 1
   if i >= 0: