diff --git a/git.inc.php b/git.inc.php
index 3eb8225..8c2d4fa 100644
--- a/git.inc.php
+++ b/git.inc.php
@@ -12,7 +12,7 @@ task('git_info', function()
   echo $info;
 });
 
-function git_do($repo, $action, &$out = NULL, $verbose = true)
+function git_do(string $repo, string $action, &$out = NULL, bool $verbose = true)
 {
   $cli = "cd $repo && git $action";
   if($verbose)
@@ -24,14 +24,16 @@ function git_do($repo, $action, &$out = NULL, $verbose = true)
     throw new Exception("Error executing command: $cli ($result)");
 }
 
-function git_is_repo($directory)
+function git_is_repo(string $directory, bool $check_root = false) : bool
 {
+  if($check_root && !is_dir("$directory/.git"))
+    return false;
   $output = [];
   git_do($directory, "rev-parse --is-inside-work-tree", $output, false);
   return !empty($output) && $output[0] === 'true';
 }
 
-function git_rev_from_commit_message($message)
+function git_rev_from_commit_message(string $message) : string
 {
   // Regular expression pattern to extract the commit hash
   $pattern = '/\b[0-9a-f]{7,40}\b/';
@@ -42,7 +44,7 @@ function git_rev_from_commit_message($message)
   return $commit_hash;
 }
 
-function get_git_last_remote_tag($repo)
+function get_git_last_remote_tag(string $repo) : string|bool
 {
   $remote_tags = [];
   git_do($repo, 'ls-remote --tags origin', $output, false);
@@ -60,7 +62,7 @@ function get_git_last_remote_tag($repo)
   return _get_last_version_tag($remote_tags);
 }
 
-function _get_last_version_tag(array $tags)
+function _get_last_version_tag(array $tags) : string|bool
 {
   if(!$tags)
     return false;
@@ -74,11 +76,11 @@ function _get_last_version_tag(array $tags)
 
 class GitVersion
 {
-  public $major;
-  public $minor;
-  public $patch;
+  public int $major;
+  public int $minor;
+  public int $patch;
 
-  static function parse($version_str)
+  static function parse($version_str) : GitVersion
   {
     $parts = explode('.', $version_str);
     if(sizeof($parts) != 3)
@@ -92,7 +94,7 @@ class GitVersion
     return $v;
   }
 
-  function bump($up_mode)
+  function bump(int $up_mode)
   {
     if($up_mode == 1)
       ++$this->patch;
@@ -111,7 +113,7 @@ class GitVersion
       throw new Exception("Unsupported up mode: $up_mode");
   }
 
-  function encode()
+  function encode() : string
   {
     return 'v'.$this->major.'.'.$this->minor.'.'.$this->patch;
   }