Req #72392 [NEW]: array_diff not working as expected due to unintuitive behavior in file()

From: sky at skyboydston dot com Operating system: Windows 8 PHP version: 7.0.7 Package: Arrays related Bug Type: Feature/Change Request Bug description:array_diff not working as expected due to unintuitive behavior in file() Description: ------------ This is part of a mini-application that takes inputs of arrays of email addresses, then compares the lists to create a final list of only valid addresses. One text file contains all of the addresses while the other two lists contain addresses that are invalid, either because their users have unsubscribed or because emails to their addresses have been undeliverable. The problem is that the array_diff() function is not working as expected. You can see from the output (shown below) that the reason is related to the output of the file() function, which will take into account newlines in .txt files by default, making array values unequal if they happen to fall on the last line in one file but on a preceding line in another file. It's necessary to actively suppress the newlines by using the FILE_IGNORE_NEW_LINES flag on file(). My suggestion is that this behavior is unintuitive and that PHP would be more user friendly if the suppression of these newlines was the default for file(). Not setting it up like that seems to be creating a situation that's fairly difficult to debug. In order for a developer to see that this is the cause of their problem in array_diff(), it's necessary to add <pre></pre> tags so that the newlines are apparent, and even then, not glaringly so as would be best. In my case, I simply happened to insert the <pre></pre> tags because I was preparing the code for other's review here and on stackoverflow.com. I believe the following post was created by others having difficulties related to this issue: http://stackoverflow.com/questions/7348280/array-diff-not-working-as-expected-what-could-be-the-reason Contents of the three files: all.txt: one@one.com two@two.com three@three.net four@four.org five@five.com unsub.txt: four@four.org two@two.com bounced.txt: one@one.com Incorrect output: Array ( [0] => one@one.com [1] => two@two.com [2] => three@three.net [3] => four@four.org [4] => five@five.com ) Array ( [0] => four@four.org [1] => two@two.com ) Array ( [0] => one@one.com ) one@one.com two@two.com three@three.net five@five.com 7.0.6 Correct output: Array ( [0] => one@one.com [1] => two@two.com [2] => three@three.net [3] => four@four.org [4] => five@five.com ) Array ( [0] => four@four.org [1] => two@two.com ) Array ( [0] => one@one.com ) three@three.net five@five.com 7.0.6 Test script: --------------- $all = array(); // Initialize the arrays we'll need $unsub = array(); $bounced = array(); $valid = array(); // Populate them and display their contents to make sure we're getting what we want. $all = file('all.txt', FILE_IGNORE_NEW_LINES); // <-- This flag can be removed to show the code which does not behave as expected. Make sure to remove it for all three files. echo '<pre>'; print_r($all); echo '</pre><br>'; $unsub = file('unsub.txt', FILE_IGNORE_NEW_LINES); echo '<pre>'; print_r($unsub); echo '</pre><br>'; $bounced = file('bounced.txt', FILE_IGNORE_NEW_LINES); echo '<pre>'; print_r($bounced); echo '</pre><br>'; $valid = array_diff($all, $unsub, $bounced); // Here's where we originally seemed to be having a problem foreach ($valid as $value) { print($value . '<br>'); } echo (PHP_VERSION); // This behavior has also been tested and is the same in version 5.6.19 -- Edit bug report at https://bugs.php.net/bug.php?id=72392&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=72392&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=72392&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=72392&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=72392&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=72392&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=72392&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=72392&r=needscript Try newer version: https://bugs.php.net/fix.php?id=72392&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=72392&r=support Expected behavior: https://bugs.php.net/fix.php?id=72392&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=72392&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=72392&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=72392&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=72392&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=72392&r=dst IIS Stability: https://bugs.php.net/fix.php?id=72392&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=72392&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=72392&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=72392&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=72392&r=mysqlcfg