Unexpected behaviour when $GLOBALS is deleted

[Pointer666]

Q	A
PHPUnit version	8.5.2
PHP version	7.2.27
Installation Method	Composer

doctrine/instantiator 1.3.0 A small, lightweight utility to instantiate objects in PHP without invoking their constructors
myclabs/deep-copy 1.9.5 Create deep copies (clones) of your objects
phar-io/manifest 1.0.3 Component for reading phar.io manifest information from a PHP Archive (PHAR)
phar-io/version 2.0.1 Library for handling version information and constraints
phpdocumentor/reflection-common 2.0.0 Common reflection classes used by phpdocumentor to reflect the code structure
phpdocumentor/reflection-docblock 4.3.4 With this component, a library can provide support for annotations via DocBlocks or otherwise retrieve information that is ...
phpdocumentor/type-resolver 1.0.1 A PSR-5 based resolver of Class names, Types and Structural Element Names
phpspec/prophecy v1.10.2 Highly opinionated mocking framework for PHP 5.3+
phpunit/php-code-coverage 7.0.10 Library that provides collection, processing, and rendering functionality for PHP code coverage information.
phpunit/php-file-iterator 2.0.2 FilterIterator implementation that filters files based on a list of suffixes.
phpunit/php-text-template 1.2.1 Simple template engine.
phpunit/php-timer 2.1.2 Utility class for timing
phpunit/php-token-stream 3.1.1 Wrapper around PHP's tokenizer extension.
phpunit/phpunit 8.5.2 The PHP Unit Testing framework.
sebastian/code-unit-reverse-lookup 1.0.1 Looks up which function or method a line of code belongs to
sebastian/comparator 3.0.2 Provides the functionality to compare PHP values for equality
sebastian/diff 3.0.2 Diff implementation
sebastian/environment 4.2.3 Provides functionality to handle HHVM/PHP environments
sebastian/exporter 3.1.2 Provides the functionality to export PHP variables for visualization
sebastian/global-state 3.0.0 Snapshotting of global state
sebastian/object-enumerator 3.0.3 Traverses array structures and object graphs to enumerate all referenced objects
sebastian/object-reflector 1.1.1 Allows reflection of object attributes, including inherited and non-public ones
sebastian/recursion-context 3.0.0 Provides functionality to recursively process PHP variables
sebastian/resource-operations 2.0.1 Provides a list of PHP built-in functions that operate on resources
sebastian/type 1.1.3 Collection of value objects that represent the types of the PHP type system
sebastian/version 2.0.1 Library that helps with managing the version number of Git-hosted PHP projects
symfony/polyfill-ctype v1.13.1 Symfony polyfill for ctype functions
theseer/tokenizer 1.1.3 A small library for converting tokenized PHP source code into XML and potentially other formats
webmozart/assert 1.6.0 Assertions to validate method input/output with nice error messages.

Summary

If the $GLOBALS array is cleared and an error occured in the test a warning is triggered inside
of phpunit and the causing error is never shown.

How to reproduce

class test extends \PHPUnit\Framework\TestCase
{
	public function SetUp(): void
	{
		$GLOBALS            = [];
	}

	public function testError()
	{
		$this->doesNotExist(); 
	}
}

result:

PHPUnit 8.5.2 by Sebastian Bergmann and contributors.

E                                                                   1 / 1 (100%)

Time: 22 ms, Memory: 4.00 MB

There was 1 error:

1) test::testError
PHP Notice:  Undefined index: _SERVER in /home/maik/test/vendor/phpunit/phpunit/src/Util/Filter.php on line 76
PHP Stack trace:
PHP   1. {main}() /home/maik/test/vendor/phpunit/phpunit/phpunit:0
PHP   2. PHPUnit\TextUI\Command::main() /home/maik/test/vendor/phpunit/phpunit/phpunit:61
PHP   3. PHPUnit\TextUI\Command->run() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/Command.php:159
PHP   4. PHPUnit\TextUI\TestRunner->doRun() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/Command.php:200
PHP   5. PHPUnit\TextUI\ResultPrinter->printResult() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/TestRunner.php:632
PHP   6. PHPUnit\TextUI\ResultPrinter->printErrors() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php:164
PHP   7. PHPUnit\TextUI\ResultPrinter->printDefects() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php:360
PHP   8. PHPUnit\TextUI\ResultPrinter->printDefect() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php:325
PHP   9. PHPUnit\TextUI\ResultPrinter->printDefectTrace() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php:334
PHP  10. PHPUnit\Framework\ExceptionWrapper->__toString() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php:351
PHP  11. PHPUnit\Util\Filter::getFilteredStacktrace() /home/maik/test/vendor/phpunit/phpunit/src/Framework/ExceptionWrapper.php:50
PHP  12. PHPUnit\Util\Filter::shouldPrintFrame() /home/maik/test/vendor/phpunit/phpunit/src/Util/Filter.php:56
PHP Fatal error:  Method PHPUnit\Framework\ExceptionWrapper::__toString() must not throw an exception, caught TypeError: realpath() expects parameter 1 to be a valid path, null given in /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php on line 0
PHP Stack trace:
PHP   1. {main}() /home/maik/test/vendor/phpunit/phpunit/phpunit:0
PHP   2. PHPUnit\TextUI\Command::main() /home/maik/test/vendor/phpunit/phpunit/phpunit:61
PHP   3. PHPUnit\TextUI\Command->run() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/Command.php:159
PHP   4. PHPUnit\TextUI\TestRunner->doRun() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/Command.php:200
PHP   5. PHPUnit\TextUI\ResultPrinter->printResult() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/TestRunner.php:632
PHP   6. PHPUnit\TextUI\ResultPrinter->printErrors() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php:164
PHP   7. PHPUnit\TextUI\ResultPrinter->printDefects() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php:360
PHP   8. PHPUnit\TextUI\ResultPrinter->printDefect() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php:325
PHP   9. PHPUnit\TextUI\ResultPrinter->printDefectTrace() /home/maik/test/vendor/phpunit/phpunit/src/TextUI/ResultPrinter.php:334

Expected behavior

I would expect the following output.

PHPUnit 8.5.2 by Sebastian Bergmann and contributors.

E                                                                   1 / 1 (100%)

Time: 22 ms, Memory: 4.00 MB

There was 1 error:

1) test::testError
Error: Call to undefined method test::doesNotExist()

/home/maik/test/test.php:14
/home/maik/test/vendor/phpunit/phpunit/phpunit:61

ERRORS!
Tests: 1, Assertions: 0, Errors: 1.

[epdenouden]

I will stitch this one up, I have unfinished business with global vars

[williamdes]

Same, I could not remove globals

[williamdes]

I had to add hacks to keep some globals listed here:
https://github.com/phpmyadmin/phpmyadmin/blob/af25c18051203db2019676120f5645972d808d18/test/classes/AbstractTestCase.php#L28

And to keep some _SERVER variables:
https://github.com/phpmyadmin/phpmyadmin/blob/af25c18051203db2019676120f5645972d808d18/test/classes/AbstractTestCase.php#L51

@sebastianbergmann what do you this about this issue ?

[sebastianbergmann]

I think that deleting $GLOBALS is a terrible idea. Anyway, I'll adapt PHPUnit to $GLOBALS being unavailable.

[williamdes]

I think that deleting $GLOBALS is a terrible idea. Anyway, I'll adapt PHPUnit to $GLOBALS being unavailable.

Could you explain why ?

For me keeping $GLOBALS between tests is also a terrible idea as they make them potentially depending on another test.

[sebastianbergmann]

For me keeping $GLOBALS between tests is also a terrible idea as they make them potentially depending on another test.

I totally agree with you.

PHPUnit can make a backup of $GLOBALS before a test and restore that backup to $GLOBALS after a test. This can be configured globally for all tests (using --globals-backup or backupGlobals="false") or on a test-by-test basis using the @backupGlobals enabled annotation.

This backup/restore functionality is expensive and is not required for clean code that does not modify $GLOBALS (and ideally not even looks at $GLOBALS). This is why this functionality is disabled by default. If your tests or your tested code interact(s) with $GLOBALS then you should enable this functionality.

By the way: the --strict-global-state option can be used to find tests that modify $GLOBALS. Careful, though, this is twice as expensive as --globals-backup because it makes two snapshots, one before the test and one after, of $GLOBALS and then compares them.

[williamdes]

Thank you for the feedback, I appreciate it !
backupGlobals="false" phpmyadmin/phpmyadmin@5bc53cc
Maybe this is the reason why I gained half time in performance (phpmyadmin/phpmyadmin#16131)

strict-global-state would be a good option for us but only for investigating.

I think the code I did in the setup/teardown will be good for us as we continue to remove $GLOBALS

By the way could you push a patch for a missing REQUEST_TIME_FLOAT it crashes the time output at the end ?

[sebastianbergmann]

strict-global-state would be a good option for us but only for investigating.

This is exactly what it is intended for. Do not always use this.

By the way could you push a patch for a missing REQUEST_TIME_FLOAT it crashes the time output at the end ?

This is taken care of in PHPUnit 9.2. I will not backport this to PHPUnit 8.5.