to note, I made a silly example, but this same problem did show up (3 times!) in a genuine glossary relating to a science course.

This is a patch which:

removes the current (unbelievably complicated and doesn't work properly as per this bug) method of stopping glossary entries including links to themselves.

adds a new method using a simple $GLOSSARY_EXCLUDECONCEPTS global - yes it's a global but it makes life infinity times easier, as you can see by the number of lines removed vs added in this patch...

only files changed are within glossary (glossary/lib.php and glossary/filter.php)

could I please get a +1 for commit to 1.9.4 (will port to 2.x at that stage assuming code is still relevant)?

I don't know enough about the glossary to spot any subtle problems in your new code (some unit tests would be nice, if the API of this function allows it). However, I like how much shorter it is.

Just one things,

foreach($concept->phrase as $concept) {
if(!in_array($concept->phrase,$GLOSSARY_EXCLUDECONCEPTS))

}

That in_array inside a loop sucks from a performance point of view. If you make it

$GLOSSARY_EXCLUDECONCEPTS=array($entry->concept => 1);

that is, put the value in the array key, the if becomes

if (!isset($GLOSSARY_EXCLUDECONCEPTS[$concept->phrase])) {

Actually, the best thing would be a bigger rewrite to put the values in $conceptlist into the array keys, then leave $GLOSSARY_EXCLUDECONCEPTS alone, and that bit of code becomes

$reducedconceptlist = $conceptlist;
foreach($GLOSSARY_EXCLUDECONCEPTS as $concept) {
if (isset($GLOSSARY_EXCLUDECONCEPTS[$concept]))

}

and probably other bits of code becomes simpler too. However, you probably don't want to make that big a change.

I considered the first suggestion but decided the code was clearer this way (normal arrays are easier to understand/document than item=>true arrays). $GLOSSARY_EXCLUDECONCEPTS is unlikely to have more than approx 3 items in so it probably doesn't matter.

btw I think array_key_exists is maybe faster than isset...

However can change this if you like. (You're right, I don't want to make the larger change suggested, but the small performance one, can do.)

Hoping to get this in today so I can move onto other things so will pester somebody else to give me ok to commit it

Since nobody else commented I checked it in and merged to 2.0. If glossary filters are suddenly broken, consider blaming me

mod/glossary/filter.php
mod/glossary/lib.php

HEAD, MOODLE_19+MERGED