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How to check php compatibility

By Eduardo García ● CTO | June 7th, 2015

Sometimes do you receive the scary mission of validating if your PHP project will continue working if we upgrade or downgrade the PHP version used in production server.

As you can imagine this is an extraordinarily complex task because you have determined what pieces of code must be changed to continue working under new server conditions and any omission could be and would be a massive responsibility above your shoulders.

Therefore, what you can do? Trust in your good judge about code compatibility sounds like a wrong approach and indeed it’s a terrible approach even though if you believe do you know well the application.

Fortunately, there is an open source project to enable you to do this check automatically, and today I will talk more specifically about the project PHPCompatibility.

Install PHP CodeSniffer

It’s possible to install PHP CodeSniffer using PEAR, but I would recommend use composer instead of PEAR.

Is necessary to inform to your system where PHP CodeSniffer binary phpcs could found after install with composer using the following command.

export PATH=~/.composer/vendor/bin:$PATH

After that, we must execute composer to install PHP CodeSniffer using the following command.

composer global require "squizlabs/php_codesniffer=2.*"

To check the installation was successful we could check running this command. This command will list the installed coding standards.

$ phpcs -i
The installed coding standards are MySource, PEAR, PHPCS, PSR1, PSR2, 
  Squiz and Zend

Those code standards are located at ~/.composer/vendor/squizlabs/php_codesniffer/CodeSniffer/Standards

Installing PHPCompatibility code standard.

To download PHPCompatibility code standard, we have to follow these instructions.

$ ~/.composer/vendor/squizlabs/php_codesniffer/CodeSniffer/Standards
$ git clone https://github.com/wimg/PHPCompatibility.git

Using phpcs -i we can double check the new code standard is available to be used.

$ phpcs -i
The installed coding standards are MySource, PEAR, PHPCompatibility, 
  PHPCS, PSR1, PSR2, Squiz and Zend

Checking compatibility

Firstly, you have to define if you a report including errors or warnings or both, in my case I want to exclude warnings to focus in fatal errors of PHP I could get after a PHP upgrade in my production server using the following configuration for phpcs.

phpcs --config-set error_severity 1
phpcs --config-set warning_severity 0

Executive report

If you want to show to your superior an executive report about how will be an upgrade/downgrade of PHP version in your application, you can get an overview report using the following command.

$ phpcs --report=source --standard=PHPCompatibility \
--extensions=php,inc,module,install --runtime-set testVersion 5.5 -pvs .

The command above analyze all files with extension .php, .inc, .module and .install because and I want to analyze a Drupal project, moreover, I want to check the compatibility of this project with PHP 5.5 showing the progress of this analysis.

This command will generate an output similar to the following list.

PHP CODE SNIFFER VIOLATION SOURCE SUMMARY
----------------------------------------------------------------------
SOURCE                                                           COUNT
----------------------------------------------------------------------
PHPCompatibility.PHP.RemovedExtensions                           365
PHPCompatibility.PHP.DeprecatedNewReference                      153
PHPCompatibility.PHP.ForbiddenNamesAsInvokedFunctions            6
PHPCompatibility.PHP.DeprecatedFunctions                         3
----------------------------------------------------------------------
A TOTAL OF 527 SNIFF VIOLATIONS WERE FOUND IN 4 SOURCES
----------------------------------------------------------------------

Time: 3 mins, 46.3 secs; Memory: 185.25Mb

Detailed report

To evaluate the statement of work to be prepared for the PHP version change, we can get a detail report in a file using this command.

phpcs --standard=PHPCompatibility --extensions=php,inc,module,install \
--report-full=/Users/enzo/Desktop/CS-report.txt \
--runtime-set testVersion 5.5 -pvs .

The command above will produce an output similar to this.

FILE: /Users/enzo/drupal/includes/common.inc
----------------------------------------------------------------------
FOUND 1 ERROR AFFECTING 1 LINE
----------------------------------------------------------------------
 1797 | ERROR | 'clone' is a reserved keyword introduced in PHP version
      |       | 5.0 and cannot be invoked as a function (T_CLONE)
      |       | (PHPCompatibility.PHP.ForbiddenNamesAsInvokedFunctions)
----------------------------------------------------------------------

I hope you found this post useful.