Absence of `mbstring` php extensions causes webmentions to fail

[miklb]

As reported in indieweb-wordpress the inclusion of the mb_convert_encoding can cause a fatal error if the mbstring php extension is not active or installed.

Report said that webmentions were not received with semantic linkbacks active, deactivating it allowed them to be received, thus why I opened it in the issue in this plugin.

When I looked for other examples of that function in core WordPress it seems if ( function_exists('mb_convert_encoding') ) is used.

@dshanske said it is a result of the php mf2 library so not sure if we need to do a PR upstream to wrap those in an if statement or do something on plugin side.

Just wanted to document so we don't forget to address.

[dshanske]

The thing is, the file in question is the PHP-MF2 Parser. So, should this be upstream?

[dshanske]

At the least, let's consider raising a flag if this happens.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.