Change #1211638 had a related patch set uploaded (by EMcFarland; author: EMcFarland):

[mediawiki/extensions/GrowthExperiments@master] Handle exception from ApiHelpPanelPostQuestion when a mentee asks a question to a nonexistent mentor

https://gerrit.wikimedia.org/r/1211638

Change #1211639 had a related patch set uploaded (by EMcFarland; author: EMcFarland):

[mediawiki/core@master] Add an exception for wikis that lack mentors.

https://gerrit.wikimedia.org/r/1211639

Change #1211639 abandoned by EMcFarland:

[mediawiki/core@master] Add an exception for wikis that lack mentors.

Reason:

I am abandoning the change in favor of adding an exception to the GrowthExperiments extension repo.

https://gerrit.wikimedia.org/r/1211639

Here are notes for how to do manual QA for this task. (I know the task isn't there yet, but I am including these notes for future QA.)
Scenario: No mentors on a wiki.

1. On a wiki that has no mentors, navigate to the Special:ApiSandbox page.
2. Select action=helppanelquestionposter.
3. For source, select "mentor-helppanel" from the dropdown.
4. Submit the request.
5. You should see an error that explains there are no mentors.

Scenario: A wiki has mentors, but a user attempts to ask a mentor a question when they themselves don't have a mentor.

1. While logged in as a user who has a mentor, navigate to Special:Homepage.
2. Click on the mentor module and navigate to Special:Homepage#/homepage/mentorship/question.
3. Type a question to your mentor, but don't publish it.
4. Open Special:Homepage in another tab as the same user. Navigate to Learn more about mentors.
5. Still in that same tab, opt out of mentorship.
6. Return to the previous tab. Attempt to publish your question. You should see the below error message.

Change #1214554 had a related patch set uploaded (by EMcFarland; author: EMcFarland):

[mediawiki/extensions/GrowthExperiments@master] MentorQuestionPoster: Refactor so ::construct works without a mentor

https://gerrit.wikimedia.org/r/1214554

Change #1214554 merged by jenkins-bot:

[mediawiki/extensions/GrowthExperiments@master] MentorQuestionPoster: Refactor so ::construct works without a mentor

https://gerrit.wikimedia.org/r/1214554

Change #1211638 merged by jenkins-bot:

[mediawiki/extensions/GrowthExperiments@master] Handle exception when mentee asks a question to a nonexistent mentor

https://gerrit.wikimedia.org/r/1211638

Thank you, @EMcFarland-WMF for the QA plan! Checked on beta - works as expected. Moving to check in production.

(1) Testing on frwiki beta (and ukwiki beta) - Special:ManageMentors list is empty.

{
    "error": {
        "code": "notmentored",
        "info": "You cannot ask a question to your mentor if you do not have a mentor.",
        "docref": "See https://fr.wikipedia.beta.wmcloud.org/w/api.php for API usage. Subscribe to the mediawiki-api-announce mailing list at <https://lists.wikimedia.org/postorius/lists/mediawiki-api-announce.lists.wikimedia.org/> for notice of API deprecations and breaking changes."
    },
    "servedby": "deployment-mediawiki13"
}

✅ Checked on cawiki wmf.10

{
    "error": {
        "code": "notmentored",
        "info": "You cannot ask a question to your mentor if you do not have a mentor.",
        "docref": "See https://ca.wikipedia.org/w/api.php for API usage. Subscribe to the mediawiki-api-announce mailing list at <https://lists.wikimedia.org/postorius/lists/mediawiki-api-announce.lists.wikimedia.org/> for notice of API deprecations and breaking changes."
    },
    "servedby": "mw-api-ext.codfw.main-667764956f-pcdmf"
}

(2) When a user opts-out from Mentorship - beta wiki

Testing notes for checking production wikis

(1)
The current api call in wmf.7 - check after deployment to production (or cawiki can be used):

{
    "error": {
        "code": "internal_api_error_Wikimedia\\Assert\\InvariantException",
        "info": "[58527291-f8b0-4842-97a5-ec0b1450821e] Caught exception of type Wikimedia\\Assert\\InvariantException",
        "errorclass": "Wikimedia\\Assert\\InvariantException"
    },
    "servedby": "mw-api-ext.codfw.main-6c9d649c6d-xh9br"
}

(2) When a user opts-out from Mentorship
testwiki wmf.7

✅ Checked testwiki wmf.10
{F71464647}