String index handling mistake in TinyMCE's JSON.php causes a PHP "Notice" message

[carlosman]

In the SpellChecker plugin for TinyMCE with a PHP backend, in file JSON.php, in lines 332 ("read" function) and 350 ("peek" function), the $this->_data string index ($this->_pos) is compared with $this->_data string length ($this->_len). These allow errors in lines 339 and 351 of their respective functions, when the $this->_pos index gets to be equal to the length of the string. This situation generates the following messages to show up in PHP servers configured to show notice-level debug information:

Notice: Uninitialized string offset: <length of _data> in <WordPress path>/wp-includes/js/tinymce/plugins/spellchecker/classes/utils/JSON.php on line 351

Notice: Uninitialized string offset: <length of _data> in <WordPress path>/wp-includes/js/tinymce/plugins/spellchecker/classes/utils/JSON.php on line 339

I will attach a patch file to illustrate how I solved this situation.

[SergeyBiryukov]

Should probably be reported upstream?

[azaozz]

The bug still exists but we don't use the spellchecker plugin any more. A ticket on ​TinyMCE's bug tracker would be better.