Introduction
I think template locator and path finder require some changes.
Sample situation: 2 templates, 3 extensions
Templates: progreen, which inherits from prosilver.
Extensions: ext1, ext2 and ext3. ext1 has prosilver templates, ext2 has prosilver and progreen templates, ext3 has "all" templates (see events)
Currently locator stores paths to templates in one dimensional array. With template inheritance and extensions, order of search looks like this:
1. styles/progreen/template/
2. styles/prosilver/template/
3. ext/ext1/styles/prosilver/template
4. ext/ext2/styles/progreen/template
5. ext/ext2/styles/prosilver/template
6. ext/ext3/styles/all/template <-- currently missing, but I think it should be added
That works great when including templates.
However, it doesn't work for events because events must include templates from all extensions.
In current version of events PR, template filter is responsible for locating templates, it uses finder for it without accounting for template inheritance. For example above, it means templates will be searched for in locations #1, #4 and #6. So it isn't searching half of directories that it should search in.
If locator is used to locate template instead of finder, it doesn't distinguish between extension and style, so sample template located within several styles in same extension, like #4 and #5, both will be included.
If all of those styles in example have template for event, correct way would be to include only templates from #1, #3, #4 and #6. #2 should not be included because #1 overrides it with template inheritance. #5 should not be included because #4 overrides it with template inheritance.
Suggestion
I suggest to solve it by changing from one dimensional list of paths to 2 dimensions: extension and paths:
['style'][0] = styles/progreen/template/
['style'][1] = styles/prosilver/template/
['ext1'][0] ext/ext1/styles/prosilver/template
['ext2'][0] = ext/ext2/styles/progreen/template
['ext2'][1] = ext/ext2/styles/prosilver/template
['ext3'][0] = ext/ext3/styles/all/template
When searching for templates for events, locator should look for first entry in each top level array. As soon as entry in second level array is found, locator should go to next top level array. Example: searching in ['style'][0] => if found, go to ['ext1'][0]. if not found, check ['style'][1]
This way only one template per extension will be included in event.
Also with this change main template path is gone. It wasn't functioning properly anyway.
Patch
Ticket: http://tracker.phpbb.com/browse/PHPBB3-10735
Patch: https://github.com/phpbb/phpbb3/pull/677
