Easiest way to detect/remove unused `use` statements from PHP codebase

Question

I\'ve searched all over for something like this but I believe the word \"use\" is perhaps too common for any helpful results:

What is the easiest way to remove all un-us

Answer 1

EDIT

I have completely rewritten it, so now it is much more powerful:

• Traits and anonymous/lambda functions are ignored
• Now taking care of catch blocks, class extensions and interfaces
• Indentation and comments don't matter
• Multiple declarations for namespace aliases work too
• Static and object class calls are recognized as "usage" ($u->getUsages())
• Full and half qualified usages are not treated

The test file, class.php:

And here the script:

content = token_get_all(file_get_contents($file));

    // we don't need and want them while parsing
    $this->removeTokens(T_COMMENT);
    $this->removeTokens(T_WHITESPACE);
  }

  public function getUnused()
  {
    $uses   = $this->getUseStatements();
    $usages = $this->getUsages();
    $unused = array();

    foreach($uses as $use) {
      if (!in_array($use, $usages)) {
        $unused[] =  $use;
      }
    }
    return $unused;
  }

  public function getUsages()
  {
    $usages = array();

    foreach($this->content as $key => $token) {

      if (!is_string($token)) {
        $t = $this->content;

        // for static calls
        if ($token[0] == T_DOUBLE_COLON) {
          // only if it is NOT full or half qualified namespace
          if ($t[$key-2][0] != T_NAMESPACE) {
            $usages[] = $t[$key-1][1];
          }
        }

        // for object instanciations
        if ($token[0] == T_NEW) {
          if ($t[$key+2][0] != T_NAMESPACE) {
            $usages[] = $t[$key+1][1];
          }
        }

        // for class extensions
        if ($token[0] == T_EXTENDS || $token[0] == T_IMPLEMENTS) {
          if ($t[$key+2][0] != T_NAMESPACE) {
            $usages[] = $t[$key+1][1];
          }
        }

        // for catch blocks
        if ($token[0] == T_CATCH) {
          if ($t[$key+3][0] != T_NAMESPACE) {
            $usages[] = $t[$key+2][1];
          }
        }
      }
    }
    return array_values(array_unique($usages));
  }

  public function getUseStatements()
  {
    $tokenUses = array();
    $level = 0;

    foreach($this->content as $key => $token) {

      // for traits, only first level uses should be captured
      if (is_string($token)) {
        if ($token == '{') {
          $level++;
        }
        if ($token == '}') {
          $level--;
        }
      }

      // capture all use statements besides trait-uses in class
      if (!is_string($token) && $token[0] == T_USE && $level == 0) {
        $tokenUses[] = $key;
      }
    }

    $useStatements = array();

    // get rid of uses in lambda functions
    foreach($tokenUses as $key => $tokenKey) {
      $i                   = $tokenKey;
      $char                = '';
      $useStatements[$key] = '';

      while($char != ';') {
        ++$i;
        $char = is_string($this->content[$i]) ? $this->content[$i] : $this->content[$i][1];

        if (!is_string($this->content[$i]) && $this->content[$i][0] == T_AS) {
          $useStatements[$key] .= ' AS ';
        } else {
          $useStatements[$key] .= $char;
        }

        if ($char == '(') {
          unset($useStatements[$key]);
          break;
        }
      }
    }

    $allUses = array();

    // get all use statements
    foreach($useStatements as $fullStmt) {
      $fullStmt = rtrim($fullStmt, ';');
      $fullStmt = preg_replace('/^.+ AS /', '', $fullStmt);
      $fullStmt = explode(',', $fullStmt);

      foreach($fullStmt as $singleStmt) {
        // $singleStmt only for full qualified use
        $fqUses[] = $singleStmt;

        $singleStmt = explode('\\', $singleStmt);
        $allUses[] = array_pop($singleStmt);
      }
    }
    return $allUses;
  }

  public function removeTokens($tokenId)
  {
    foreach($this->content as $key => $token) {
      if (isset($token[0]) && $token[0] == $tokenId) {
        unset($this->content[$key]);
      }
    }
    // reindex
    $this->content = array_values($this->content);
  }

}

$unused = new UseStatementSanitzier('class.php');

print_r($unused->getUnused());

/*
Returns:
Array
(
  [0] => NSname
  [1] => NSname1
)
*/