Bootstrap Theme always sends content to "side-pre", even when there isn't one

As requested by damyon, this is now a late addition to MDL-39824 as it ha been integrated. It does solve the original issue too and impoves the solution in MDL-39824 with less code changes and smaller layout files.

Old description:

There is an error in the logic of bootstrapbase and clean themes layout. general.php which results in side-pre always being output, even if the $THEME->layouts for the page affected excludes side-pre.

Lines 143-162 have the error in bootstrapbase/layout/general.php, and lines 172 to 202 have the error in the clean theme.

The logic error is that the code tests to see if $layout is not content-only. If true then the code renders the html for pre-and-post or for side-pre-only, and drops by error into "if (!right_to_left())" regardless of what $layout is set to.

Therefore if $layout is set to side-post-only there is no HTML code generated, but "echo $OUTPUT->blocks_for_region('side-pre')" is executed regardless.

One possible fix is to change

                if (!right_to_left()) {

                    echo $OUTPUT->blocks_for_region('side-pre');

                } else if ($hassidepost) {

                    echo $OUTPUT->blocks_for_region('side-post');

                } ?>

to

                if(!$layout === 'side-post-only') {

                    if (!right_to_left()) {

                        echo $OUTPUT->blocks_for_region('side-pre');

                    } else if ($hassidepost) {

                        echo $OUTPUT->blocks_for_region('side-post');

                    }

                }

However, it is probably better to fix the logic completely so that the echo $OUTPUT->blocks_for_region only occurs when $layout is 'pre-and-post' or 'side-pre-only'

How to test:

Turn on Debug to Developer and Theme Design Mode on

Copy the entire section of $THEME->layouts from bootstrapbase/config.php and paste into config.php of clean/config.php

In config.php of theme standard, and theme clean (please alter both!), change the front page layout to:

    // The site home page.

    'frontpage' => array(

        'file' => 'general_frontpage.php',

        'regions' => array('side-pre'),

        'defaultregion' => 'side-pre',

        'options' => array('nonavbar'=>true),

Purge caches after saving the two config.php files

Select Site Admininstration / Appearance / Theme / Theme Selector and select Clean theme. Go to the front page (ALL should be OK)

Select Site Admininstration / Appearance / Theme / Theme Selector and select Standard theme. Go to the home page (ALL should be OK)

Re edit the two config.php $THEME->layout to:

    // The site home page.

    'frontpage' => array(

        'file' => 'general_frontpage.php',

        'regions' => array('side-post'),

        'defaultregion' => 'side-post',

        'options' => array('nonavbar'=>true),

Purge caches again

Go to front page - all is still OK

Select Site Admininstration / Appearance / Theme / Theme Selector and select Clean theme. Go to the front page

Now you get the Theme header but before you get to the main body Moodle throws an exception - "Coding error detected, it must be fixed by a programmer: Trying to reference an unknown block region side-pre"

Fix the logic error in clean/layout/general.php

Purge all caches

The error should be corrected.

NOTE: There appears to be another bug but I will raise a second issue for that one. The problem is, if blocks are configured to appear in side-post, then when the $THEME-layout for a page says only use side-pre, the blocks disappear when using theme Clean. This doesn't happen with theme Standard. Please link this other issue as it may be related.