fix: restore model from session messages on load (#346)

Author: jensenojs

lua/opencode/core.lua

@@ -528,15 +528,30 @@ M.ensure_current_mode = Promise.async(function()
   return true
 end)
 
----Initialize current model if it's not already set.
----@return string|nil The current model (or the default model, if configured)
+---Initialize current model from messages or config.
+---@return string|nil The current model
 M.initialize_current_model = Promise.async(function()
+  if state.messages then
+    for i = #state.messages, 1, -1 do
+      local msg = state.messages[i]
+      if msg and msg.info and msg.info.modelID and msg.info.providerID then
+        local model_str = msg.info.providerID .. '/' .. msg.info.modelID
+        if state.current_model ~= model_str then
+          state.model.set_model(model_str)
+        end
+        if msg.info.mode and state.current_mode ~= msg.info.mode then
+          state.model.set_mode(msg.info.mode)
+        end
+        return state.current_model
+      end
+    end
+  end
+
   if state.current_model then
     return state.current_model
   end
 
   local cfg = require('opencode.config_file').get_opencode_config():await()
-
   if cfg and cfg.model and cfg.model ~= '' then
     state.model.set_model(cfg.model)
   end

lua/opencode/ui/renderer.lua

@@ -93,24 +93,6 @@ local function fetch_session()
   return require('opencode.session').get_messages(session)
 end
 
----Set the current model/mode from the most recent assistant message
-local function set_model_and_mode_from_messages()
-  if not state.messages then
-    return
-  end
-  for i = #state.messages, 1, -1 do
-    local message = state.messages[i]
-    if message and message.info and message.info.modelID and message.info.providerID then
-      state.model.set_model(message.info.providerID .. '/' .. message.info.modelID)
-      if message.info.mode then
-        state.model.set_mode(message.info.mode)
-      end
-      return
-    end
-  end
-  require('opencode.core').initialize_current_model()
-end
-
 ---Render all messages and parts from session_data into the output buffer
 ---Called after a full session fetch or when revert state changes
 ---@param session_data OpencodeMessage[]
@@ -122,7 +104,6 @@ function M._render_full_session_data(session_data)
   end
 
   local revert_index = nil
-  local set_mode_from_messages = not state.current_model
 
   flush.begin_bulk_mode()
 
@@ -163,9 +144,7 @@ function M._render_full_session_data(session_data)
   flush.flush()
   flush.end_bulk_mode()
 
-  if set_mode_from_messages then
-    set_model_and_mode_from_messages()
-  end
+  require('opencode.core').initialize_current_model()
 
   M.scroll_to_bottom(true)