node.html.twig intermittently being ignored

Additional info ...

I've now discovered that this affects some custom content types too.

Turning off the Internal Page cache did not stop this problem.

Clearing All Caches immediately corrects the problem, and all twig templates are again correctly read ... for a while.

Even after upgrading core to 8.4.0, this is still an issue. There's little obvious logic to which nodes are effected, and there's only a handful at a time. My custom theme is a subtheme of Bartik (being a subtheme of Classy).

So to reiterate, if I clear all caches manually, all the faulty node teasers display correctly until the next cron run.

Why isn't the automated cron task doing the same thing, and refreshing ALL cached data? Is that "normal" for D8?

OK. I've circumvented this issue by duplicating node.html.twig and renaming the copy as node--teaser.html.twig so that there is also a specific child theme template for all teasers.

Weird.

My temporary "fix" to create specific teaser twig templates hasn't solved this problem.

The nodes that skip the node.html.twig template (or variants thereof e.g. node--page--teaser.html.twig) are usually the most recently created or edited content. This happens after an automated cron task.

When I clear all caches manually, all teasers in Views are correctly rendered again.

I'd be really grateful for any guidance or suggestions here, especially if there is a way to ensure that cron clears ALL caches every time.

For the record, in case this ever happens to anyone else, I found the culprit and have solved the problem. I did this by trawling through the database tables looking for similarities between affected nodes.

I discovered that for one of the Text Formats (Basic HTML), I had unwisely or accidentally disabled the filter "Correct faulty and chopped off HTML". After this was re-enabled and monitoring the site for some time, this issue of ignoring the relevant node template after cron hasn't recurred.

Reopening this issue because I am again seeing this problem ...

I am now convinced this is related to the use (or not) of the CKEditor as a text editor.

Node teasers that bypass the template are apparently those that are using a Body/Summary text format that does NOT use the CKEditor, e.g. Restricted HTML or Plain text.

Yes @joelpittet, I still see this issue arise from time to time (as per #13 screenshot), and always with the Basic Page type.

For Basic Page content, I have enabled custom settings for both Teaser and RSS displays, but not Full Content. I've done this to easily hide custom fields.

Just updated to 8.8.4 and within hours, this problem reared its head again. I'm more and more suspicious of the CK Editor having "issues", as this was the crux of the 8.8.4 update.

Well done @JFKwad. However I can't figure how to implement that code in #24. Please tell us more. Which file did you add this to?

Here are some more clues...

@JFKiwad helps us confidently point to a caching problem. I still have to manually flush all caches to restore affected node teasers to the expected output of the node.html.twig template, but it doesn't last long.

Every time I update Drupal core or add new content, this problem recurs repeatedly, presumably after every cron run, and usually only to some of the most recently created nodes. Just updated core to 8.8.6, and sure enough, it frequently happens again.

The affected teasers are being displayed through a taxonomy_term View.

In case it may be relevant, additional active modules (non core) are ctools, fontyourface, honeypot, metatag, schema_metatag, pathauto, rabbit_hole, captcha, recaptcha, token.

Two years later, I am still hoping that someone with the know-how will investigate and instigate a fix. Please help.

I won't say this is a resounding "fix", but it sure helps.

There seems to be a conflict between two core cache modules; Internal Page Cache [page_cache] & Internal Dynamic Page Cache [dynamic_page_cache].

I disabled Internal Page Cache [page_cache], and there now seems to be some stability in parsing the node.twig template.

Two posts led me to try this;
https://drupal.stackexchange.com/questions/235828/twig-drupal-8-custom-cache-context-not-working-in-node-preprocess
https://wimleers.com/article/drupal-8-dynamic-page-cache

This problem won't go away, so let's start again.

Drupal 8.9.2 / PHP 7.3

My theme is a child of Bartik. I'm not a complete novice with Drupal theming, but my PHP skills are very basic.

I have copied and customized these two twig templates from Bartik into my own theme templates folder;
views-view-unformatted.html.twig
node--page--teaser.html.twig

Most of the time, everything displays perfectly until you modify the content of a node (and the example below is content of type 'Basic Page').

After modifying a node (and Cron has run), upon reloading the Taxonomy Term page that displays teasers using these two templates, node--page--teaser.html.twig is largely ignored for some nodes, and not others.

With twig debugging enabled, I can see that THEME HOOK NODE is not being implemented for those nodes.

Here is part of the views-row HTML output. You can see that the ARTICLE tag appears here (generated by the teaser.html.twig template), but the fields that are output are rendered AFTER that tag is closed, and not within it. The H2 node title tag is empty too. Note that the node creation and username info is displayed, and it shouldn't be, making it immediately obvious that this is not rendering properly.

<div class="views-row">
<article class="node node--type- teaser-teaser node--unpublished clearfix">
  <header>
    
      <h2 class="node__title">
        <a href="" rel="bookmark"></a>
      </h2>
    
  </header>
  <div class="node__content clearfix">
    
  </div>
</article>


<!-- THEME DEBUG -->
<!-- THEME HOOK: 'field' -->
<!-- FILE NAME SUGGESTIONS:
   * field--node--title--page.html.twig
   x field--node--title.html.twig
   * field--node--page.html.twig
   * field--title.html.twig
   * field--string.html.twig
   * field.html.twig
-->
<!-- BEGIN OUTPUT from 'core/themes/bartik/templates/classy/field/field--node--title.html.twig' -->
<span property="schema:name" data-quickedit-field-id="node/473/title/en/teaser" class="field field--name-title field--type-string field--label-hidden">Gravity</span>

<!-- END OUTPUT from 'core/themes/bartik/templates/classy/field/field--node--title.html.twig' -->

<!-- THEME DEBUG -->
<!-- THEME HOOK: 'field' -->
<!-- FILE NAME SUGGESTIONS:
   * field--node--uid--page.html.twig
   x field--node--uid.html.twig
   * field--node--page.html.twig
   * field--uid.html.twig
   * field--entity-reference.html.twig
   * field.html.twig
-->
<!-- BEGIN OUTPUT from 'core/themes/bartik/templates/classy/field/field--node--uid.html.twig' -->
<span rel="schema:author" data-quickedit-field-id="node/473/uid/en/teaser" class="field field--name-uid field--type-entity-reference field--label-hidden">

<!-- THEME DEBUG -->
<!-- THEME HOOK: 'username' -->
<!-- BEGIN OUTPUT from 'core/themes/bartik/templates/classy/user/username.html.twig' -->
<a title="View user profile." href="/user/1" lang="" about="/user/1" typeof="schema:Person" property="schema:name" datatype="" class="username">Garry</a>
<!-- END OUTPUT from 'core/themes/bartik/templates/classy/user/username.html.twig' -->

</span>

<!-- END OUTPUT from 'core/themes/bartik/templates/classy/field/field--node--uid.html.twig' -->

Is there something obvious that I may have missed in creating my custom child theme?

Do I need to add a preprocess or hook function to my custom-child-of-bartik.theme file (which is currently empty)?

Do I need to add a list of my custom templates to my theme's libraries.yml file?

Any help would be appreciated.

FYI - I have recently experimented rather exhaustively on disabling/enabling various Views caching modes and modules. Also with disabling contributor modules, so far without finding the cause.

To reiterate, the problem occurs on a Taxonomy Term page displaying Teasers.

Most interesting is that only the most recently modified or created nodes are affected, and usually after the next cron task runs. The only way to restore the Teasers back to normal is to manually Clear All Caches.

Happy to provide extra info as needed. This issue is slowly driving me insane, so I expect that is what is required.

Even though there exists a View Mode called 'Taxonomy Term Page', this View always uses the Default display mode. I know this because I just added the following code 'view-mode-' ~ view_mode|clean_class to the list of classes to render in taxonomy-term.html.twig (which renders 'view-mode-default'). Note that there is apparently nowhere in the Drupal 8 UI to specify which Display Mode the Taxonomy Term View should use. Could this be relevant?

I just want to add that the nodes that are repeatedly affected by this problem are those created since around October 2018. I've even trawled through the database tables to see if there are any glaring differences between more recent content and earlier nodes. Nothing looks abnormal.

I've even tried a clean install of 8.9.5 in my local MAMP, then adding all third party modules and my theme files, and finally importing the current database. No change.

I wish that automated cron would execute drupal_flush_all_caches. It might help because cron seems to trigger the fault after content has changed, and manually launching 'Clear All Caches' on the Performance page is the only way to fix it, as the caches rebuild over time.

(I'm also retracting my previous comment that only basic page node types are affected. Not true.)

Yes @jplana, I can consistently reproduce this issue.

All I need do is edit or add new content listed on a paginated Views taxonomy page. Usually the problem appears either immediately, or within an hour or two, apparently depending on cron activity. I am seeing the same nodes repeatedly affected, all created since approx Oct 18 as noted in #34 above.

Once the problem recurs, and after a day or two of frequently hitting ''Clear All Caches'' on the Performance page, things stabilize and I don't see the issue again until the next content change.

@jplana - I have seen this issue in my local MAMP environment too. I've never setup or used xdebug before, but I'll have a go.

@jplana — I hope this is what you are looking for... Still working my way through setting up Xdebug... It's complicated.

I've just updated my localhost MAMP install to D8.9.9. I only use the core Automated Cron module. It is set to run every 3 hours.

STATUS REPORT
General System Information
Drupal Version 8.9.9
Last Cron Run Last run 4 minutes 3 seconds ago
(more information)
Run cron
Web Server
Apache/2.2.34 (Unix) mod_wsgi/3.5 Python/2.7.13 PHP/7.4.2 mod_ssl/2.2.34 OpenSSL/1.0.2o DAV/2 mod_fastcgi/mod_fastcgi-SNAP-0910052141 mod_perl/2.0.11 Perl/v5.24.0
PHP
Version
7.4.2 (more information)
Memory limit
512M
Database
Version
5.7.26
System
MySQL, MariaDB, Percona Server, or equivalent
Checked
Access to update.php
Protected
Configuration files
Protected
Database system
MySQL, MariaDB, Percona Server, or equivalent
Database system version
5.7.26
Database updates
Up to date
Drupal core security coverage
Covered until 2021-Nov
Visit the release cycle overview for more information on supported releases.
Drupal core update status
Up to date
Entity/field definitions
Up to date
File system
Writable (public download method)
GD library
bundled (2.1.0 compatible)
GD library PNG support
bundled (2.1.0 compatible)
Image toolkit
gd
GD2 image manipulation toolkit
Metatag
Schema.org Metatag is installed
The Schema.org Metatag module is installed.
Module and theme update status
Up to date
Node Access Permissions
Disabled
If the site is experiencing problems with permissions to content, you may have to rebuild the permissions cache. Rebuilding will remove all privileges to content and replace them with permissions based on the current modules and settings. Rebuilding may take some time if there is a lot of content or complex permission settings. After rebuilding has completed, content will automatically use the new permissions. Rebuild permissions
PHP
7.4.2 (more information)
PHP APCu caching
Enabled (32 MB)
Memory available: 31.44 MB.
PHP extensions
Enabled
PHP memory limit
512M
PHP OPcode caching
Enabled
Random number generation
Successful
Search index progress
100% (0 remaining)
Serialized data types
Not enabled
The Serialization API is configured with the recommended default and outputs typed values (integers, Booleans, or strings as appropriate) for REST and other applications. If your site or applications require string output, you can enable backwards compatibility mode.
Trusted Host Settings
Enabled
The trusted_host_patterns setting is set to allow ^localhost$
Unicode library
PHP Mbstring Extension
Update notifications
Enabled
Upload progress
Not enabled
Your server is not capable of displaying file upload progress. File upload progress requires PHP be run with mod_php or PHP-FPM and not as FastCGI.

@jplana — I've been trying to make Xdebug work.

After gleaning various bit of info online, I added these lines to both php.ini files in MAMP.

zend_extension="/Applications/MAMP/bin/php/php7.4.2/lib/php/extensions/no-debug-non-zts-20190902/xdebug.so"
xdebug.remote_autostart=1
xdebug.remote_enable=1
xdebug.remote_host=localhost
xdebug.remote_port=9000
xdebug.remote_handler=dbgp
xdebug.max_nesting_level=1000

http://localhost:8888/admin/reports/status/php confirms that this was successful.

I installed the Xdebug-ext add-on to Firefox and matched the IDE Key to that shown in http://localhost:8888/admin/reports/status/php . I then enabled the Xdebug-ext ladybug for the tab where I am viewing localhost pages.

I installed the Twig Xdebug module in my local MAMP install. It seems to be the most relevant.
As instructed, I added {{ breakpoint() }} to my theme node.html.twig template.

Sure enough, I modified some content in my local site instance, and the node.html.twig template issue reappears immediately, specifically affecting the node just modified.

I still can't figure out how to examine the Twig Xdebug module output. I have no idea how to determine if it's working. Opening the Firefox Web-developer Debugger window seems to only show js errors.

---------

Firefox Debugger consistently shows these js errors when loading any page, even Admin pages using the Seven theme.

/core/assets/vendor/jquery
jquery.min.js

SyntaxError: Element.querySelectorAll: '\' is not a valid selector
SyntaxError: Element.querySelectorAll: '*,:x' is not a valid selector
SyntaxError: Element.matches: '[s!='']:x' is not a valid selector

--------------

There are multiple identical errors in
/Applications/MAMP/logs/mysql_error_log.err

2020-11-20T00:20:46.949924Z 0 [Warning] InnoDB: Table mysql/innodb_index_stats has length mismatch in the column name table_name. Please run mysql_upgrade

--------------

There are no recent additions to
/Applications/MAMP/logs/apache_error.log
/Applications/MAMP/logs/php_error.log

--------------

What have I missed? I can't believe that Phpstorm is a mandatory install.

Thanks @philipnorton42. This could be really helpful.

I agree that the overlapping/sharing of the render cache would be an excellent place to look for the root cause.

My offending Taxonomy View contains two Page views (taxonomy/term/%, taxonomy/term/%/images), and one Block, but no Feed. One thing I haven't tried yet, is to split the three display components of my View into three entirely separate Views.

I just tried splitting the offending View into three separate Views as per #43, but this makes no difference.

Regarding #45 & #46 above, on a whim I tried re-creating a Feed for Taxonomy Term, and then disabling it, but that changes nothing.

Also, I just tested updating my site to D9.1 in my local environment, and sadly the issue is still evident.

In response to comments #48 and #49, I've decided to complicate my site even more, and create a custom node View Mode to replace the Teaser in my paginated Taxonomy Term View, so that the cache is not shared with RSS or anything else. (All other supplied display modes are not an option for me.)

Effectively I replicated how the Teaser is displayed for all my content types, and changed over my Taxonomy Term view to use that new custom View Mode instead of the inbuilt Teaser. To complete the changeover, I had to duplicate a few customised theme node--TYPE--teaser.html.twig templates, then rename them to reference the new View Mode, and tweak my theme CSS that previously referenced the .node--view-mode-teaser display class.

I hope I never see this problem again. It's been driving me nuts.

Thanks to everyone who has so far offered tips, suggestions and has spent time trying to find this elusive bug.