[PHP-BUG] Req #70507 [NEW]: Combination of is_file() + include (e.g. "include_if_exists")

From:             andreas at dqxtech dot net
Operating system: Linux
PHP version:      7.0.0RC2
Package:          PHP Language Specification
Bug Type:         Feature/Change Request
Bug description:Combination of is_file() + include (e.g. "include_if_exists")

Description:
------------
For slightly improved class loader performance, it would be nice to have
a combination of is_file() + include, as a new language construct.

Currently, include raises a warning if the file does not exist, is not
accessible, or is not a file.

This means that a class loader cache that is not sure if the file exists
needs to call is_file() before include. And to be strict, it would also
have to call is_readable().

The new language construct would include the file if it exists, and
return either TRUE or FALSE to indicate the success. This way the script
does not need to hit the filesystem more than once.

An explicit return value of the file can be ignored, because this is
mostly designed for class files.

There could be some more interesting behavior on failure. E.g. instead
of just returning FALSE, it could return an object with an indication
what went wrong.. Or this information could be retrieved from
elsewhere.

The goal is to optimize the performance in case of success, not on
failure.

-------

This being said: Maybe this is all not necessary, if the
compiler/optimizer can automatically merge the is_file() and the
include.

Test script:
---------------
spl_autoload_register('my_autoload_callback');

function my_autoload_callback($class) {
  $file = my_autoload_cache_lookup($class);
  if (!$file) {
    return;
  }
  if (true === include_if_exists $file) {
    // Done with the classloader.
    return;
  }
  my_autoload_cache_unset($class);
  $file = my_autoload_psr4_lookup($class);
  if (!$file) {
    return;
  }
  if (true === include_if_exists $file) {
    my_autoload_cache_set($class, $file);
  }
}


-- 
Edit bug report at https://bugs.php.net/bug.php?id=70507&edit=1
-- 
Try a snapshot (PHP 5.4):   https://bugs.php.net/fix.php?id=70507&r=trysnapshot54
Try a snapshot (PHP 5.5):   https://bugs.php.net/fix.php?id=70507&r=trysnapshot55
Try a snapshot (trunk):     https://bugs.php.net/fix.php?id=70507&r=trysnapshottrunk
Fixed in SVN:               https://bugs.php.net/fix.php?id=70507&r=fixed
Fixed in release:           https://bugs.php.net/fix.php?id=70507&r=alreadyfixed
Need backtrace:             https://bugs.php.net/fix.php?id=70507&r=needtrace
Need Reproduce Script:      https://bugs.php.net/fix.php?id=70507&r=needscript
Try newer version:          https://bugs.php.net/fix.php?id=70507&r=oldversion
Not developer issue:        https://bugs.php.net/fix.php?id=70507&r=support
Expected behavior:          https://bugs.php.net/fix.php?id=70507&r=notwrong
Not enough info:            https://bugs.php.net/fix.php?id=70507&r=notenoughinfo
Submitted twice:            https://bugs.php.net/fix.php?id=70507&r=submittedtwice
register_globals:           https://bugs.php.net/fix.php?id=70507&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=70507&r=php4
Daylight Savings:           https://bugs.php.net/fix.php?id=70507&r=dst
IIS Stability:              https://bugs.php.net/fix.php?id=70507&r=isapi
Install GNU Sed:            https://bugs.php.net/fix.php?id=70507&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=70507&r=float
No Zend Extensions:         https://bugs.php.net/fix.php?id=70507&r=nozend
MySQL Configuration Error:  https://bugs.php.net/fix.php?id=70507&r=mysqlcfg