fix(libraries): resolve tcpdf incompatibility with PHP 7.2

[Benunc]

User Story

As a give developer, I want to use open source and PHP 7.2-compatible libraries to generate PDFs.

TCPDF is currently not compatible with PHP 7.2, specifically the deprecated funciton each() at give/includes/libraries/tcpdf/tcpdf.php on line 16548. It appears that development has stopped on that library at https://github.com/tecnickcom/TCPDF and the new library is not complete/stable yet.

Current Behavior

I currently get an error on PHP 7.2 when trying to generate a PDF.

Expected Behavior

I expect to have PHP 7.2 compatibility.

Steps to Reproduce

1. Update the local PHP version to 7.2.x
2. Generate a custom PDF using one of the methods that uses TCPDF. (may require an add-on, but the library itself lives in Give Core)
3. anywhere the each() function is will generate a fatal error Deprecated: The each() function is deprecated. This message will be suppressed on further calls in /app/public/wp-content/plugins/give/includes/libraries/tcpdf/tcpdf.php on line 16548

Related

• https://secure.helpscout.net/conversation/609733462/20691/

Tasks

• Update TCPDF library to 6.2.17.
• Test all PDF functionality in Give and its add-ons using PHP 7.2.

[kevinwhoffman]

This should be fixed in a more recent release of TCPDF according to this PR.

The version of TCPDF in Give is 6.2.13 but the latest release available is 6.2.17.

@raftaar1191 please look into updating TCPDF and post whether you feel there would be any side effects to upgrading. We'll also need to test existing PDF functionality in PHP 7.2.

[raftaar1191]

@kevinwhoffman

I check the TCPDF Version 6.2.13 I can there are some outdated PHP functions which are not going to work in PHP 7.2.

I also had a look into TCPDF Version 6.2.17 and that is working fine in PHP version 5.3 to 7.2

We just need to update the library and do some testing to check the PDF is generated properly or not in Give Core as well in Add-on

[raftaar1191]

Slack Call Summery: https://givewp.slack.com/archives/C0FAGC83C/p1530171569000136