fix(ui): add defensive guards for async window/buffer operations (#264)

- topbar: pcall wrap winbar setting + win_is_valid check before render
- loading_animation: buf_is_valid guard + pcall for extmark operations
- curl: explicit is_running boolean flag instead of job.pid check
  (job.pid persists after process exit, causing false health check positives)
- Add curl lifecycle tests

Author: jensenojs

lua/opencode/curl.lua

@@ -78,6 +78,8 @@ function M.request(opts)
 
   if opts.stream then
     local buffer = ''
+    -- job.pid is not cleared on process exit
+    local is_running = true
 
     local job_opts = {
       stdout = function(err, chunk)
@@ -114,20 +116,26 @@ function M.request(opts)
       job_opts.stdin = opts.body
     end
 
-    local job = vim.system(args, job_opts, opts.on_exit and function(result)
-      -- Flush any remaining buffer content
+    local job = vim.system(args, job_opts, function(result)
+      is_running = false
+
       if buffer and buffer ~= '' then
         opts.stream(nil, buffer)
       end
-      opts.on_exit(result.code, result.signal)
-    end or nil)
+
+      if opts.on_exit then
+        opts.on_exit(result.code, result.signal)
+      end
+    end)
 
     return {
       _job = job,
       is_running = function()
-        return job and job.pid ~= nil
+        return is_running
       end,
       shutdown = function()
+        -- Flip state before kill so callers immediately observe shutdown.
+        is_running = false
         if job and job.pid then
           pcall(function()
             job:kill(15) -- SIGTERM

lua/opencode/ui/loading_animation.lua

@@ -97,8 +97,8 @@ end
 function M.stop()
   M._clear_animation_timer()
   M._animation.current_frame = 1
-  if state.windows and state.windows.footer_buf then
-    vim.api.nvim_buf_clear_namespace(state.windows.footer_buf, M._animation.ns_id, 0, -1)
+  if state.windows and state.windows.footer_buf and vim.api.nvim_buf_is_valid(state.windows.footer_buf) then
+    pcall(vim.api.nvim_buf_clear_namespace, state.windows.footer_buf, M._animation.ns_id, 0, -1)
   end
 end
 

lua/opencode/ui/topbar.lua

@@ -16,7 +16,10 @@ local function format_token_info()
   if state.current_model then
     if config.ui.display_context_size then
       local provider, model = state.current_model:match('^(.-)/(.+)$')
-      local model_info = config_file.get_model_info(provider, model)
+      local ok, model_info = pcall(config_file.get_model_info, provider, model)
+      if not ok then
+        model_info = nil
+      end
       local limit = state.tokens_count and model_info and model_info.limit and model_info.limit.context or 0
       table.insert(parts, util.format_number(state.tokens_count) or nil)
       if limit > 0 then
@@ -92,7 +95,7 @@ function M.render()
       return
     end
     local win = state.windows.output_win
-    if not win then
+    if not win or not vim.api.nvim_win_is_valid(win) then
       return
     end
 

tests/unit/curl_spec.lua

@@ -0,0 +1,57 @@
+local curl = require('opencode.curl')
+
+describe('curl stream handle lifecycle', function()
+  local original_system
+
+  before_each(function()
+    original_system = vim.system
+  end)
+
+  after_each(function()
+    vim.system = original_system
+  end)
+
+  it('marks stream handle as stopped after process exit', function()
+    local on_complete
+
+    vim.system = function(_, _, cb)
+      on_complete = cb
+      return {
+        pid = 123,
+        kill = function() end,
+      }
+    end
+
+    local handle = curl.request({
+      url = 'http://127.0.0.1:1/event',
+      stream = function() end,
+    })
+
+    assert.is_true(handle.is_running())
+    on_complete({ code = 0, signal = 0 })
+    assert.is_false(handle.is_running())
+  end)
+
+  it('marks stream handle as stopped on shutdown', function()
+    local killed = false
+
+    vim.system = function(_, _, _)
+      return {
+        pid = 123,
+        kill = function()
+          killed = true
+        end,
+      }
+    end
+
+    local handle = curl.request({
+      url = 'http://127.0.0.1:1/event',
+      stream = function() end,
+    })
+
+    handle.shutdown()
+
+    assert.is_true(killed)
+    assert.is_false(handle.is_running())
+  end)
+end)