In #29169 we added a NULLS NOT DISTINCT option to the unique index on problem_check_trackers. This is to enforce uniqueness even when the target is NULL. (Postgres considers all NULLs to be distinct by default.)
However, this only works in PG15. In PG13 it does nothing.
This commit adds a default dummy string value __NULL__ to target. Since it's a string, PG13 will be able to correctly identify duplicate records.
We need a way to disable certain checks programatically, e.g. on Discourse hosting. This PR adds a configuration option for this, and makes it so that disabled checks aren't run as part of #run_all.
We support a low-level construct called "inline checks", which you can use to register a problem ad-hoc from within application code.
Problems registered by inline checks never show up in the admin dashboard, this is because when loading the dashboard, we run all realtime checks and look for problems. Because of an oversight, we considered inline checks to be "realtime", causing them to be run and clear their problem status.
To fix this, we don't consider inline checks to be realtime, to prevent them from running when loading the admin dashboard.
The OutOfDateThemes problem check is using an old method of setting the message, by overriding #message. It should instead use #translation_keys. (By chance I noticed the same thing applies to UnreachableThemes.
This PR introduces a basic AdminNotice model to store these notices. Admin notices are categorized by their source/type (currently only notices from problem check.) They also have a priority.
Previously the problem check registry simply looked at the subclasses of ProblemCheck. This was causing some confusion in environments where eager loading is not enabled, as the registry would appear empty as a result of the classes never being referenced (and thus never loaded.)
This PR changes the approach to a more explicit one. I followed other implementations (bookmarkable and hashtag autocomplete.) As a bonus, this now has a neat plugin entry point as well.
This was originally introduced in #26071, but that PR was closed, because the requirements changed. This PR lifts only the relevant parts, since they are a prerequisite for the new admin notice system.
In #26122 we promoted all problem checks defined as class methods on AdminDashboardData to their own first-class ProblemCheck instances.
This PR continues that by promoting problem checks that are implemented as blocks as well. This includes updating a couple plugins that have problem checks.
In AdminDashboardData we have a bunch of problem checks implemented as methods on that class. This PR absolves it of the responsibility by promoting each of those checks to a first class ProblemCheck. This way each of them can have their own priority and arbitrary functionality can be isolated in its own class.
Think "extract class" refactoring over and over. Since they were all moved we can also get rid of the @@problem_syms class variable which was basically the old version of the registry now replaced by ProblemCheck.realtime.
In addition AdminDashboardData::Problem value object has been entirely replaced with the new ProblemCheck::Problem (with compatible API).
Lastly, I added some RSpec matchers to simplify testing of problem checks and provide helpful error messages when assertions fail.
There are a couple of reasons for this.
The first one is practical, and related to eager loading. Since /lib is not eager loaded, when the application boots, ProblemCheck["identifier"] will be nil because the child classes aren't loaded.
The second one is more conceptual. There turns out to be a lot of inter-dependencies between the part of the problem check system that live in /app and the parts that live in /lib, which probably suggests it should all go in /app.
