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Debug bar does not appear on one specific front-end page, despite appearing on all others.


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I wondered if anyone knows how to troubleshoot this. I have one specific page where the the Tracy debug bar doesn't load, so I can't access the output of bd() and other Tracy functions. The debug bar does appear in the ProcessWire back-end and every other front-end page I checked.

My first thought was that, for some reason, ProcessWire didn't think I was logged in as a superuser on that page, but I echoed $user->name, and it showed my superuser username. For good measure, I also echoed $user->hasPermission('tracy-debugger'), and got the output "1".

I checked the TracyDebugger module settings to see if I misconfigured something, and couldn't find anything obviously wrong:

  • "Enable TracyDebugger" is checked.
  • "Output mode" is set to "DEVELOPMENT".
  • "Force superusers" and "guest users into DEVELOPMENT mode" are both unchecked. I checked them and reloaded just in case and got the same behavior.
  • "Show debug bar" is checked for "Frontend" and "Backend".
  • "No debug bar in…" is unchecked for all modes.

I'm sure the solution will seem obvious in hindsight, I just can't foresee it.

Thanks in advance for any guidance!


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No. No errors in the browser console, nor do I see any errors logged in ProcessWire's error log under "Setup » Logs". For what it's worth, the page does not seem to be loading any front-end scripts at all from TracyDebugger. On other pages where the debug bar loads, I see a huge wodge of markup appended to the markup I wrote, starting with <!-- Tracy Debug Bar -->. The affected page has no appended script elements at all.

I see I can make the debug bar appear if I uncomment two lines of code that were throwing a fatal error.

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19 hours ago, johnstephens said:

I see I can make the debug bar appear if I uncomment two lines of code that were throwing a fatal error.

I'd be interested to see that code to see if there is something I can do to prevent Tracey from not capturing that error and breaking it from loading.

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I'm willing to share it, but I don't know how much would be useful.

I started with something like this:

This problem of TracyDebugger failing to load came up after adding code to compose the site's parent/child hierarchy using the imported articles.

The specific lines that throw the fatal error are these:

$newArticle->alert->setLanguageValue($en, $article['alert_en']);
$newArticle->alert->setLanguageValue($es, $article['alert_es']);

When those lines are included, Tracy's debug bar loads and shows me the stack trace of the error. The reported error is "Call to a member function setLanguageValue() on null", which doesn't make sense to me. I verified that the 'alert' field is attached to the template AND that it's correctly configured as a multi-language textarea (as opposed to a regular textarea, which wouldn't support the setLanguageValue() method).

I commented out those lines to simply dump the $newArticle object using bd(), and the actual script executes without any errors or warnings—but then Tracy's debug bar vanishes. I wonder what could stop the debug bar from loading?

I hope this helps. Thank you, @adrian!

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  • 2 weeks later...

I've done a lot of testing, and my hunch is that the script is running out of memory—specifically when I invoke bd().

What I'm doing is this:

  1. Query a MySQL database with $database->query().
  2. Use foreach to loop through the results.
  3. Each iteration of the loop, I select a $parent page based on data from the query and create a new page with $pages->add().

If I invoke bd() within the loop, TracyDebugger fails to load. If I don't invoke bd() in the loop, the debug bar loads.

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Hi @johnstephens - thanks for looking into it further - sorry I didn't respond to your last message - I didn't really see anything I could use to reproduce it.

It does sound like you might be onto something with the memory error idea.

I am curious what is in your bd() call - are there a lot or heavy objects being dumped? How many results are you looping through?

If I try to dump too many items, eg:

for($i=0;$i<99999999;$i++) {

And I do get an out of memory fatal error and the debug bar fails to load, but I fixed it by increasing the "Reversed memory size" option in Tracy's config settings. Please let me know if that works for you.

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