Moodle Plugins directory: Formulas question type: Comments

Tuesday, 9 December 2025, 4:57 PM - Philipp Imhof

Tue, 09 Dec 2025 08:57:32 GMT

by Philipp Imhof.

Hello Ivan and thanks for reaching out.

I'm afraid this is not a bug, but the intended (although debatable) behaviour. I'll give you four examples. Say the model answer is 1 m.

- If the student enters 1 m or 100 cm, they get full marks, no deduction.
- If the student enters 1, they get the unit penalty deducted, so 0.9 points.
- If the student enters 1 kg, they get the unit penalty deducted, so 0.9 points.
- If the student enters 1 cm, their answer is considered wrong and they get no points at all.

The unit penalty is only used if the student completely omits the unit or if they use an incompatible unit.

As I said above, this is debatable. Some people might argue that a student typing 1 cm instead of 1 m only made a unit error or that their error is less important than if they had written 1 kg. Other people would then probably say that if a bridge only supports 100 kg instead of 100 tons, that's more than just a unit error.

Best regards

Tuesday, 9 December 2025, 7:01 AM - Ivan Muñoz

Mon, 08 Dec 2025 23:01:32 GMT

by Ivan Muñoz.

Subject: Possible bug in unit penalty behaviour (Moodle 4.5.2)

Hello Dominique,

I have been using the Formulas question type for many years. In the past I managed my own Moodle site, but now everything is handled by my educational institution. I believe I have found an issue related to scoring.

In my questions, students must include the correct units. When they do not, I apply a unit penalty of 0.1, which I configure in the question settings. However, I have noticed that Moodle is not subtracting 10% of the grade as expected. Instead, it seems to subtract 100%, marking the response as completely wrong instead of giving partial credit.

My institution is currently using Moodle 4.5.2, updated yearly. This issue did not occur last academic year under the previous Moodle version.

Could you let me know if this is a known bug in the plugin? If so, I could request that my institution update the plugin to a newer version to resolve the problem.

Thank you very much for your work and your time.

Best regards,

Monday, 20 October 2025, 2:54 PM - Bruno Dogančić

Mon, 20 Oct 2025 06:54:19 GMT

by Bruno Dogančić.

Dear Dominique and Philipp,

Thank you so much!

Cheers!

Thursday, 16 October 2025, 2:06 AM - Dominique Bauer

Wed, 15 Oct 2025 18:06:16 GMT

by Dominique Bauer.

The automatic login has been re-enabled. You don’t need the login credentials, but just in case, here they are:

Username: student
Password: Formulas.1

Wednesday, 15 October 2025, 10:58 PM - Philipp Imhof

Wed, 15 Oct 2025 14:58:49 GMT

by Philipp Imhof.

Hello Bruno and Eric. The documentation page is managed by my colleague Prof. Dominique Bauer. I have sent him a message and I am sure that he will soon find out what is happening. Best regards

Wednesday, 15 October 2025, 10:55 PM - Eric Anderson

Wed, 15 Oct 2025 14:55:49 GMT

by Eric Anderson.

Hi,
I'm trying to access the documentation website, and anytime I click on any part, it wants me to login, but I see no place to register for your Moodle.

Saturday, 11 October 2025, 1:09 PM - Bruno Dogančić

Sat, 11 Oct 2025 05:09:20 GMT

by Bruno Dogančić.

Hey there! First, I want to express my heartfelt gratitude for such a great plugin; it helped me keep some of my hair intact while I struggled with calculated multiple choice questions using LaTeX and the frustrating Moodle database.

A few days ago I was enjoying creating content and studying documentation at https://dynamiccourseware.org/, but today I am unable to reach content --- it prompts me for a username and password (I have tried different browsers, but there is no "automatic login for guests", which I think worked for the last few days).

Help would be super appreciated, as I need to keep the ongoing semester. 🙏

Kind regards,
Bruno

Monday, 15 September 2025, 5:59 PM - Philipp Imhof

Mon, 15 Sep 2025 09:59:44 GMT

by Philipp Imhof.

Hello Nikola

Thanks for your message. I can see what is happening. Would you mind opening an issue on GitHub for the problem?

I have a fix in mind for the problems Ω and µ. I am afraid that % will be a bit more complicated, because that symbol is used as the modulo operator and % is not a unit. However, as the modulo operator is not allowed for students, I am sure that a solution is possible for that as well.

Best regards

Monday, 15 September 2025, 4:39 PM - Nikola Bogosavljevic

Mon, 15 Sep 2025 08:39:31 GMT

by Nikola Bogosavljevic.

Dear Philipp,

I'm not sure if this issue is already known, but as we are currently facing it and have no solution, I will try to post it here.

After upgrading to Moodle version 4.5.5, we have had issues with the units "Ω", "µ" and "%".

For example:
Unit settings: Ω
Other rules settings: 1 ohm = 1 Ω ; 1 kohm = 1 kΩ ; 1 Mohm = 1 MΩ; 1 mohm = 1 mΩ

If a student answers with 1 Ω, it will be marked as a wrong answer. Only 'ohm' will be accepted.

Other example with µ:
Unit settings: µ
Other rules settings: 1 uA = 1 µA

Only "u" will be accepted, not "µ".

We don't have any other rule settings with "%"; it is only for the unit setting "%". This will always be marked as wrong.

Hope you can help here!

Thank you a lot!

BR
Nikola

Wednesday, 10 September 2025, 5:18 PM - Philipp Imhof

Wed, 10 Sep 2025 09:18:15 GMT

by Philipp Imhof.

Thanks Kevin. The issue is actually already fixed in the main branch. I have just not released a new version yet.

Wednesday, 10 September 2025, 5:11 PM - Kevin Hipwell

Wed, 10 Sep 2025 09:11:58 GMT

by Kevin Hipwell.

Hi Victoria Shimanovich,

I created this patch to fix the issue you are having.

--- question/type/formulas/backup/moodle2/restore_qtype_formulas_plugin.class.php 2025-09-05 15:43:37.857758954 +0100
+++ question/type/formulas/backup/moodle2/restore_qtype_formulas_plugin.class.php 2025-09-05 15:45:00.742738212 +0100
@@ -203,10 +203,12 @@

// Also, we must make sure that the specific options like varsrandom etc. are added to
// the questiondata object.
- $questiondata->options = (object) array_merge(
- (array) $questiondata->options,
- $backupdata['plugin_qtype_formulas_question']['formulas'][0],
- );
+ if (isset($backupdata["plugin_qtype_formulas_question"]['formulas'])) {
+ $questiondata->options = (object)array_merge(
+ (array)$questiondata->options,
+ $backupdata['plugin_qtype_formulas_question']['formulas'][0],
+ );
+ }

return $questiondata;
}

Saturday, 30 August 2025, 6:21 AM - Victoria Shimanovich

Fri, 29 Aug 2025 22:21:51 GMT

by Victoria Shimanovich.

I am experiencing issues with copying/restoring quizzes and courses. The debugging output consistently points to formulas qtype even when a quiz/course I am copying/restoring does not use this question type.
I have Moodle 4.5.5, formulas qtype plugin 6.1.2 (installed today and attempt to restore a course was made after the plugin was updated)
Here is the debugging output after the latest attempt (Developer debugging is turned on) after I tried to restore a course from backup to a new course. The debugging output is identical when I tried to copy a course or a quiz before. It doesn't matter if there are formulas type questions in a course or quiz I try to copy. Also, the result (and debugging output) is identical when I try to copy a course from Site Administration -> Courses -> Copy course or when I try to restore a course from already existing backup (no issues creating a backup), or when I try to copy a quiz. (Developer debugging is turned on) after I tried to restore a course from backup to a new course

Exception - array_merge(): Argument #2 must be of type array, null given

More information about this error
Debug info:
Error code: generalexceptionmessage
Stack trace:

line 206 of /question/type/formulas/backup/moodle2/restore_qtype_formulas_plugin.class.php: TypeError thrown
line 206 of /question/type/formulas/backup/moodle2/restore_qtype_formulas_plugin.class.php: call to array_merge()
line 117 of /backup/util/helper/restore_questions_parser_processor.class.php: call to restore_qtype_formulas_plugin::convert_backup_to_questiondata()
line 150 of /backup/util/xml/parser/processors/grouped_parser_processor.class.php: call to restore_questions_parser_processor->dispatch_chunk()
line 207 of /backup/util/xml/parser/progressive_parser.class.php: call to grouped_parser_processor->after_path()
line 287 of /backup/util/xml/parser/progressive_parser.class.php: call to progressive_parser->inform_end()
line ? of unknownfile: call to progressive_parser->end_tag()
line 178 of /backup/util/xml/parser/progressive_parser.class.php: call to xml_parse()
line 157 of /backup/util/xml/parser/progressive_parser.class.php: call to progressive_parser->parse()
line 464 of /backup/util/dbops/restore_dbops.class.php: call to progressive_parser->process()
line 177 of /backup/util/helper/restore_prechecks_helper.class.php: call to restore_dbops::load_categories_and_questions_to_tempids()
line 454 of /backup/controller/restore_controller.class.php: call to restore_prechecks_helper::execute_prechecks()
line 997 of /backup/util/ui/restore_ui_stage.class.php: call to restore_controller->execute_precheck()
line 367 of /backup/util/ui/restore_ui.class.php: call to restore_ui_stage_process->process()
line 134 of /backup/restore.php: call to restore_ui->requires_substage()

I also suspect that the same issue is causing the following failure of daily tasks: Clean backup tables, logs and files (core\task\backup_cleanup_task)

I filed bug report on GitHub. Please help me solve this ussue, I was trying to solve it since April and getting nowhere
Thank you in advance!

Monday, 16 June 2025, 3:22 PM - Philipp Imhof

Mon, 16 Jun 2025 07:22:27 GMT

by Philipp Imhof.

Dear users

We have just released version 6.0.4, another maintenance release. It fixes a bug with strings and one with MathJax previews. It also adds full support for PHP-like escape sequences in strings, especially the use of Unicode characters via the code point.

Best regards

Saturday, 7 June 2025, 4:08 AM - Philipp Imhof

Fri, 06 Jun 2025 20:08:15 GMT

by Philipp Imhof.

Dear users

We are currently releasing version 6.0.3 of the Formulas question plugin. It is a bugfix and maintenance release. We recommend installing the update in the near future, as it fixes problems with the automatic grading of multi-part questions. Also, it improves backwards compatibility with 5.x versions and, for people using Moodle 5.0, makes sure everything will continue to work nicely once you start using MathJax v3.

Best regards

Tuesday, 3 June 2025, 11:36 PM - Philipp Imhof

Tue, 03 Jun 2025 15:36:28 GMT

by Philipp Imhof.

Hello Fabio.

Thanks for your feedback and for telling me about that problem. At first glance, it (unfortunately...for me) sounds more like a bug than like something you do wrong. I will look into it and provide a fix as quickly as possible. I opened an issue on GitHub, so you can see the progress: https://github.com/FormulasQuestion/moodle-qtype_formulas/issues/219

Best regards