Does not work on php 5.6

[dotboris]

This module claims to support php 5.4 and up but when I run the latest version on php 5.6 it fails with a syntax error.

$ php --version
PHP 5.6.39 (cli) (built: Dec  7 2018 08:27:47)
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies
    with Xdebug v2.5.5, Copyright (c) 2002-2017, by Derick Rethans
$ composer show sirbrillig/phpcs-variable-analysis
name     : sirbrillig/phpcs-variable-analysis
descrip. : A PHPCS sniff to detect problems with variables.
keywords :
versions : * v2.6.2
type     : phpcodesniffer-standard
license  : BSD 2-Clause "Simplified" License (BSD-2-Clause) (OSI approved) https://spdx.org/licenses/BSD-2-Clause.html#licenseText
source   : [git] https://github.com/sirbrillig/phpcs-variable-analysis.git a31046c32e95cff4062856a3eb78770dd1bc1e48
dist     : [zip] https://api.github.com/repos/sirbrillig/phpcs-variable-analysis/zipball/a31046c32e95cff4062856a3eb78770dd1bc1e48 a31046c32e95cff4062856a3eb78770dd1bc1e48
path     : /.../vendor/sirbrillig/phpcs-variable-analysis
names    : sirbrillig/phpcs-variable-analysis

autoload
psr-4
VariableAnalysis\ => VariableAnalysis/

requires
php >=5.4.0

requires (dev)
dealerdirect/phpcodesniffer-composer-installer ^0.4.4
limedeck/phpunit-detailed-printer ^3.1
phpunit/phpunit ^6.5
sirbrillig/phpcs-import-detection ^1.1
squizlabs/php_codesniffer ^3.1
$ composer lint
> phpcs
PHP Parse error:  syntax error, unexpected '?' in /.../vendor/sirbrillig/phpcs-variable-analysis/VariableAnalysis/Sniffs/CodeAnalysis/VariableAnalysisSniff.php on line 1062
PHP Stack trace:
PHP   1. {main}() /.../vendor/squizlabs/php_codesniffer/bin/phpcs:0
PHP   2. PHP_CodeSniffer\Runner->runPHPCS() /.../vendor/squizlabs/php_codesniffer/bin/phpcs:18
PHP   3. PHP_CodeSniffer\Runner->init() /.../vendor/squizlabs/php_codesniffer/src/Runner.php:70
PHP   4. PHP_CodeSniffer\Ruleset->__construct() /.../vendor/squizlabs/php_codesniffer/src/Runner.php:332
PHP   5. PHP_CodeSniffer\Ruleset->registerSniffs() /.../vendor/squizlabs/php_codesniffer/src/Ruleset.php:216
PHP   6. PHP_CodeSniffer\Autoload::loadFile() /.../vendor/squizlabs/php_codesniffer/src/Ruleset.php:1146

Parse error: syntax error, unexpected '?' in /.../vendor/sirbrillig/phpcs-variable-analysis/VariableAnalysis/Sniffs/CodeAnalysis/VariableAnalysisSniff.php on line 1062

Call Stack:
    0.0024     230080   1. {main}() /.../vendor/squizlabs/php_codesniffer/bin/phpcs:0
    0.0061     709800   2. PHP_CodeSniffer\Runner->runPHPCS() /.../vendor/squizlabs/php_codesniffer/bin/phpcs:18
    0.0176    1318656   3. PHP_CodeSniffer\Runner->init() /.../vendor/squizlabs/php_codesniffer/src/Runner.php:70
    0.0221    1685624   4. PHP_CodeSniffer\Ruleset->__construct() /.../vendor/squizlabs/php_codesniffer/src/Runner.php:332
    0.0326    1731848   5. PHP_CodeSniffer\Ruleset->registerSniffs() /.../vendor/squizlabs/php_codesniffer/src/Ruleset.php:216
    0.0594    4048304   6. PHP_CodeSniffer\Autoload::loadFile() /.../vendor/squizlabs/php_codesniffer/src/Ruleset.php:1146

Script phpcs handling the lint event returned with error code 255

I think that the issue comes from https://github.com/sirbrillig/phpcs-variable-analysis/blob/master/VariableAnalysis/Sniffs/CodeAnalysis/VariableAnalysisSniff.php#L1062 which uses the ?? syntax. I think that this is a new syntax that only showed up in php 7+

[sirbrillig]

Oops! Thank you for noticing that. I've had this issue before.

[sirbrillig]

I updated the automated tests so hopefully this will be noticed next time it happens.