refactor(gitcommit): address Gemini code review feedback

- Remove duplicate is_windows/shell_quote from command.lua, import from git_utils
- Refactor contributors() to limit results in Lua instead of platform-specific pipes
- Simplify filter_diff() by consolidating file path extraction logic

Author: jinzhongjia

lua/codecompanion/_extensions/gitcommit/git_utils.lua

@@ -118,27 +118,12 @@ function M.filter_diff(diff_content, exclude_patterns)
   local skip_current_file = false
 
   for _, line in ipairs(lines) do
-    local file_match = line:match("^diff %-%-git a/(.*) b/")
-    if file_match then
-      current_file = file_match
-      table.insert(all_files, current_file)
-      skip_current_file = M.should_exclude_file(current_file, exclude_patterns)
-      if skip_current_file then
-        table.insert(excluded_files, current_file)
-      end
-    end
+    local file_path = line:match("^diff %-%-git a/(.*) b/")
+      or line:match("^%+%+%+ b/(.*)")
+      or line:match("^%-%-%-a/(.*)")
 
-    local plus_file = line:match("^%+%+%+ b/(.*)")
-    local minus_file = line:match("^%-%-%-a/(.*)")
-    if plus_file then
-      current_file = plus_file
-      table.insert(all_files, current_file)
-      skip_current_file = M.should_exclude_file(current_file, exclude_patterns)
-      if skip_current_file then
-        table.insert(excluded_files, current_file)
-      end
-    elseif minus_file then
-      current_file = minus_file
+    if file_path then
+      current_file = file_path
       table.insert(all_files, current_file)
       skip_current_file = M.should_exclude_file(current_file, exclude_patterns)
       if skip_current_file then

lua/codecompanion/_extensions/gitcommit/tools/command.lua

@@ -4,24 +4,10 @@
 
 local M = {}
 
---- Check if running on Windows
----@return boolean
-local function is_windows()
-  return vim.loop.os_uname().sysname == "Windows_NT"
-end
+local GitUtils = require("codecompanion._extensions.gitcommit.git_utils")
 
---- Quote a string for shell command (Windows uses double quotes, Unix uses single quotes)
----@param str string The string to quote
----@return string
-local function shell_quote(str)
-  if is_windows() then
-    -- Windows CMD: use double quotes, escape internal double quotes with \"
-    return '"' .. str:gsub('"', '\\"') .. '"'
-  else
-    -- Unix: use single quotes, escape internal single quotes
-    return "'" .. str:gsub("'", "'\\''") .. "'"
-  end
-end
+local is_windows = GitUtils.is_windows
+local shell_quote = GitUtils.shell_quote
 
 --------------------------------------------------------------------------------
 -- CommandBuilder: Pure functions for generating git command strings
@@ -244,15 +230,9 @@ function CommandBuilder.diff_commits(commit1, commit2, file_path)
 end
 
 ---Build git shortlog (contributors) command
----@param count? number Number of top contributors
 ---@return string command
-function CommandBuilder.contributors(count)
-  count = count or 10
-  if is_windows() then
-    return string.format("git shortlog -sn | Select-Object -First %d", count)
-  else
-    return string.format("git shortlog -sn | head -%d", count)
-  end
+function CommandBuilder.contributors()
+  return "git shortlog -sn"
 end
 
 ---Build git log search command

lua/codecompanion/_extensions/gitcommit/tools/git.lua

@@ -414,8 +414,19 @@ function GitTool.get_contributors(count)
       "✗ Not in a git repository",
       "<gitContributorsTool>fail: Not in a git repository</gitContributorsTool>"
   end
-  local cmd = CommandBuilder.contributors(count)
+  count = count or 10
+  local cmd = CommandBuilder.contributors()
   local success, output = CommandExecutor.run(cmd)
+  if success and output then
+    local lines = vim.split(output, "\n")
+    local limited_lines = {}
+    for i = 1, math.min(count, #lines) do
+      if lines[i] and lines[i] ~= "" then
+        table.insert(limited_lines, lines[i])
+      end
+    end
+    output = table.concat(limited_lines, "\n")
+  end
   local user_msg, llm_msg = format_git_response("contributors", success, output)
   return success, output, user_msg, llm_msg
 end