fix(render): fix gg E565 and gate load_more on has_unrendered

- Remove expr=true from gg keymap (causes E565 during buffer write)
- Gate scroll-to-top load_more on has_unrendered, not bare line number
- Fix load_more_messages treating nil as 'needs loading'

Author: jensenojs

lua/opencode/ui/output_window.lua

@@ -596,12 +596,11 @@ function M.setup_keymaps(windows)
 
   -- When lazy-render is active, gg only reaches the top of rendered content.
   -- Load all messages first so gg reaches the true start of history.
-  -- See tests/unit/renderer_lazy_spec.lua: "gg loads all messages and makes them searchable"
   vim.keymap.set('n', 'gg', function()
     local renderer = require('opencode.ui.renderer')
     renderer.load_all_messages()
-    return 'gg'
-  end, { buffer = windows.output_buf, expr = true, remap = true })
+    vim.api.nvim_win_set_cursor(0, { 1, 0 })
+  end, { buffer = windows.output_buf })
 end
 
 ---@param windows OpencodeWindowState
@@ -678,17 +677,22 @@ function M.setup_autocmds(windows, group)
         pcall(vim.api.nvim_win_set_cursor, windows.output_win, { 1, 0 })
       end
     end, 150)
-  vim.api.nvim_create_autocmd('WinScrolled', {
-    group = group,
-    buffer = windows.output_buf,
-    callback = function()
-      M.sync_cursor_with_viewport(windows.output_win)
-      local ok, cursor = pcall(vim.api.nvim_win_get_cursor, windows.output_win)
-      if ok and cursor and cursor[1] <= 3 then
-        debounced_load_more()
-      end
-    end,
-  })
+    vim.api.nvim_create_autocmd('WinScrolled', {
+      group = group,
+      buffer = windows.output_buf,
+      callback = function()
+        M.sync_cursor_with_viewport(windows.output_win)
+        local ctx = require('opencode.ui.renderer.ctx')
+        local has_unrendered = ctx.lazy_render_count ~= nil
+          and ctx.lazy_render_count < #state.messages
+        if has_unrendered then
+          local ok, cursor = pcall(vim.api.nvim_win_get_cursor, windows.output_win)
+          if ok and cursor and cursor[1] <= 3 then
+            debounced_load_more()
+          end
+        end
+      end,
+    })
 end
 
 ---Clear the output buffer and all namespaces.

lua/opencode/ui/renderer.lua

@@ -448,17 +448,20 @@ function M.load_more_messages()
   if not state.messages then
     return false
   end
+  -- nil means no lazy limit → all messages already rendered
+  if not ctx.lazy_render_count then
+    return false
+  end
   local total = #get_visible_session_messages(state.messages)
   if total == 0 then
     return false
   end
-  local current = ctx.lazy_render_count or math.min(get_initial_render_count(), total)
-  if current >= total then
+  if ctx.lazy_render_count >= total then
     return false
   end
 
   -- Load another viewport's worth
-  ctx.lazy_render_count = math.min(current + get_initial_render_count(), total)
+  ctx.lazy_render_count = math.min(ctx.lazy_render_count + get_initial_render_count(), total)
   M.render_from_cache(state.messages)
   return true
 end
@@ -475,8 +478,8 @@ function M.load_all_messages()
   if total == 0 then
     return false
   end
-  local current = ctx.lazy_render_count or 0
-  if current >= total then
+  -- nil means no lazy limit → all messages already rendered
+  if not ctx.lazy_render_count or ctx.lazy_render_count >= total then
     return false
   end
 

tests/unit/renderer_lazy_spec.lua

@@ -209,6 +209,67 @@ describe('lazy render', function()
     end
   end)
 
+  it('load_more_messages returns false when all messages already rendered', function()
+    -- No lazy_render_count means all messages rendered — no unrendered content
+    local session_data = make_session_data(50) -- 100 messages total
+    renderer._render_full_session_data(session_data)
+
+    -- lazy_render_count was set by _render_full_session_data; verify the guard
+    -- After full render with a lazy limit that covers everything, load_more returns false
+    ctx.lazy_render_count = 100
+    assert.is_false(renderer.load_more_messages(),
+      'should return false when lazy_render_count covers all messages')
+
+    -- nil means no lazy limit at all → nothing to load
+    ctx.lazy_render_count = nil
+    assert.is_false(renderer.load_more_messages(),
+      'should return false when lazy_render_count is nil')
+  end)
+
+  it('load_more_messages returns true only when unrendered messages exist', function()
+    local session_data = make_session_data(50) -- 100 messages total
+
+    ctx.lazy_render_count = 10
+    renderer._render_full_session_data(session_data)
+
+    -- Stub render_from_cache to avoid test-env dependency
+    local stub = require('luassert.stub')
+    local _rfc = stub(renderer, 'render_from_cache')
+
+    -- 10 rendered out of 100 → has unrendered → load_more should work
+    assert.is_true(renderer.load_more_messages(),
+      'should return true when unrendered messages exist')
+
+    _rfc:revert()
+  end)
+
+  it('has_unrendered gates scroll-to-top load_more', function()
+    -- When lazy_render_count covers all messages, scrolling to top
+    -- should NOT trigger load_more. This tests the guard condition
+    -- that prevents spurious loads when everything is already rendered.
+    local session_data = make_session_data(50) -- 100 messages total
+
+    -- Case 1: all rendered (lazy_render_count covers everything)
+    ctx.lazy_render_count = 100
+    renderer._render_full_session_data(session_data)
+    assert.is_false(renderer.load_more_messages(),
+      'no load_more when lazy_render_count covers all messages')
+
+    -- Case 2: partial render → load_more returns true
+    local stub = require('luassert.stub')
+    local _rfc = stub(renderer, 'render_from_cache')
+    ctx.lazy_render_count = 10
+    renderer._render_full_session_data(session_data)
+    assert.is_true(renderer.load_more_messages(),
+      'load_more returns true when unrendered messages exist')
+    _rfc:revert()
+
+    -- Case 3: nil (never set) → load_more returns false
+    ctx.lazy_render_count = nil
+    assert.is_false(renderer.load_more_messages(),
+      'no load_more when lazy_render_count is nil')
+  end)
+
   it('load_all_messages renders everything and makes it searchable', function()
     local session_data = make_session_data(50) -- 100 messages total