[Django] #32558: Fail tests when unhandled thread exceptions occur

[Django]

#32558: Fail tests when unhandled thread exceptions occur
---------------------------------------------+------------------------
Reporter: Adam Johnson | Owner: nobody
Type: New feature | Status: new
Component: Testing framework | Version: dev
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
---------------------------------------------+------------------------
Pair of #32557 and its discussion.

In Python it's possible for a thread to be started, quit with an
exception, and this exception never get seen since the main thread doesn't
call `join()` on the failed thread.

Since Python 3.8 it's possible to detect such a case by installing a hook
at `threading.excepthook`:
https://docs.python.org/3.9/library/threading.html#threading.excepthook

pytest recently added such a hook, alongside the unraisable exception
hook: https://github.com/pytest-dev/pytest/pull/8055

I think we can do similarly here, since an exception in a non-main thread
could indicate a problem with code. This is especially pertinent in the
async world where sync code can be run in threads through `sync_to_async`

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Ticket URL: <https://code.djangoproject.com/ticket/32558>
Django <https://code.djangoproject.com/>
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[Django]

#32558: Fail tests when unhandled thread exceptions occur

-----------------------------------+------------------------------------

Reporter: Adam Johnson | Owner: nobody
Type: New feature | Status: new
Component: Testing framework | Version: dev

Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted

Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0

-----------------------------------+------------------------------------
Changes (by Mariusz Felisiak):

* cc: Carlton Gibson, Tom Forbes, Chris Jerdonek (added)
* stage: Unreviewed => Accepted

Comment:

Tentatively accepted. As with #32557, I would like to check this in
practice.

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Ticket URL: <https://code.djangoproject.com/ticket/32558#comment:1>

[Django]

#32558: Fail tests when unhandled thread exceptions occur

-----------------------------------+-------------------------------------
Reporter: Adam Johnson | Owner: VIZZARD-X
Type: New feature | Status: assigned

Component: Testing framework | Version: dev

Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted

Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0

-----------------------------------+-------------------------------------
Changes (by VIZZARD-X):

* owner: nobody => VIZZARD-X
* status: new => assigned

--
Ticket URL: <https://code.djangoproject.com/ticket/32558#comment:2>

[Django]

#32558: Fail tests when unhandled thread exceptions occur

-----------------------------------+-------------------------------------
Reporter: Adam Johnson | Owner: VIZZARD-X
Type: New feature | Status: assigned

Component: Testing framework | Version: dev

Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted

Has patch: 1 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0

-----------------------------------+-------------------------------------
Changes (by VIZZARD-X):

* cc: VIZZARD-X (added)
* has_patch: 0 => 1

Comment:

[https://github.com/django/django/pull/21926 PR]
--
Ticket URL: <https://code.djangoproject.com/ticket/32558#comment:3>