From b3014e9c86c4ffc5f459ff5e0dd19e80b08d2277 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <62671086+barrettruth@users.noreply.github.com>
Date: Thu, 5 Mar 2026 15:31:47 -0500
Subject: [PATCH] fix(setup): clear output buffer when switching contests
 (#313)

## Problem

`setup_problem` only cleared the output buffer when `old_problem_id ~=
problem_id`. If two different contests share a problem with the same ID
(e.g. both have `a`), the condition is false and stale output from the
previous contest remains visible.

## Solution

Clear the output buffer at the top of `proceed()` in `setup_contest`
whenever `is_new_contest` is true, before any problem setup runs.

Closes #303.
---
 lua/cp/setup.lua | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lua/cp/setup.lua b/lua/cp/setup.lua
index eb7ba8c..7a33cd0 100644
--- a/lua/cp/setup.lua
+++ b/lua/cp/setup.lua
@@ -182,6 +182,12 @@ function M.setup_contest(platform, contest_id, problem_id, language)
   cache.load()
 
   local function proceed(contest_data)
+    if is_new_contest then
+      local io_state = state.get_io_view_state()
+      if io_state and io_state.output_buf and vim.api.nvim_buf_is_valid(io_state.output_buf) then
+        require('cp.utils').update_buffer_content(io_state.output_buf, {}, nil, nil)
+      end
+    end
     local problems = contest_data.problems
     local pid = problem_id and problem_id or problems[1].id
     M.setup_problem(pid, language)