fix(gitcommit): 优化参数校验与响应格式

- 增加参数校验辅助函数，提升健壮性
- 统一各工具响应格式，便于维护和扩展
- 修复部分注释与边界条件判断
- 优化错误处理，确保一致性

Author: jinzhongjia

lua/codecompanion/_extensions/gitcommit/buffer.lua

@@ -97,9 +97,12 @@ function Buffer._generate_and_insert_commit_message(bufnr)
   -- Get relevant changes (staged or amend)
   local diff, context = Git.get_contextual_diff()
   if not diff then
-    local msg = context == "no_changes"
-        and (Git.is_amending() and "No changes to amend" or "No staged changes found. Please stage your changes first.")
-      or ("Failed to get git changes, context=" .. tostring(context))
+    local msg
+    if context == "no_changes" then
+      msg = Git.is_amending() and "No changes to amend" or "No staged changes found. Please stage your changes first."
+    else
+      msg = "Failed to get git changes, context=" .. tostring(context)
+    end
     vim.notify(msg, vim.log.levels.ERROR)
     return
   end

lua/codecompanion/_extensions/gitcommit/generator.lua

@@ -122,25 +122,25 @@ function Generator._handle_response(err, data, adapter, callback)
     return callback(nil, "No response received from LLM")
   end
 
-  -- Process successful response
-  if data then
-    local result = _adapter.handlers.chat_output(_adapter, data)
-    if result and result.status then
-      if result.status == CONSTANTS.STATUS_SUCCESS then
-        local content = result.output and result.output.content
-        if content and vim.trim(content) ~= "" then
-          return callback(vim.trim(content), nil)
-        else
-          return callback(nil, "Generated content is empty")
-        end
-      elseif result.status == CONSTANTS.STATUS_ERROR then
-        local error_msg = result.output or "Unknown error occurred"
-        return callback(nil, error_msg)
-      end
-    end
+  -- Process the LLM response
+  local result = _adapter.handlers.chat_output(_adapter, data)
+  if not (result and result.status) then
+    return callback(nil, "No valid response received")
   end
 
-  return callback(nil, "No valid response received")
+  if result.status == CONSTANTS.STATUS_SUCCESS then
+    local content = result.output and result.output.content
+    if content and vim.trim(content) ~= "" then
+      return callback(vim.trim(content), nil)
+    else
+      return callback(nil, "Generated content is empty")
+    end
+  elseif result.status == CONSTANTS.STATUS_ERROR then
+    local error_msg = result.output or "Unknown error occurred"
+    return callback(nil, error_msg)
+  else
+    return callback(nil, "Unexpected response status: " .. tostring(result.status))
+  end
 end
 
 return Generator

lua/codecompanion/_extensions/gitcommit/git.lua

@@ -68,8 +68,8 @@ function Git._filter_diff(diff_content)
     end
   end
 
-  -- 如果所有涉及的文件都被排除，则返回原始 diff
-  if #all_files > 0 and #excluded_files == #all_files then
+  -- If all files are excluded, return original diff to avoid empty output
+  if #all_files > 0 and #excluded_files >= #all_files then
     return diff_content
   end
 

lua/codecompanion/_extensions/gitcommit/init.lua

@@ -20,9 +20,12 @@ function M.generate_commit_message()
   -- Get relevant changes (staged or amend)
   local diff, context = Git.get_contextual_diff()
   if not diff then
-    local msg = context == "no_changes"
-        and (Git.is_amending() and "No changes to amend" or "No staged changes found. Please stage your changes first.")
-      or "Failed to get git changes"
+    local msg
+    if context == "no_changes" then
+      msg = Git.is_amending() and "No changes to amend" or "No staged changes found. Please stage your changes first."
+    else
+      msg = "Failed to get git changes"
+    end
     vim.notify(msg, vim.log.levels.ERROR)
     return
   end