The `posts` relation on `Topic` is not ordered. Using `Topic.posts.first`
is basically the same as asking for a random post, it will depend on DB
order. This breaks on Topic merge and split for example.
Additionally, a huge problem with that is that it forces active record down
a slow path. `Topic.posts.first` is extremely slow on giant topics, since
it has no default ordering it appears AR materializes the entire set prior
to doing `first`.
This commit also illustrates the importance of testing, initially I only
fixed the second instance of the problem in `post_validator.rb` but testing
revealed that the problem was repeated at the top of the file.
Longer term we should consider a larger change of default ordering the posts
relations so people do not fall down this trap anymore.
We use the `id` of the upload to calculate a `depth` partition in the
filename. This test would fail if your database had a higher seed
because the depth it was looking for was hard coded to 1.
The solution was to not save the records (which is faster anyway) and
specify the `id` of the upload to make the hash deterministic.
SiteSettingExtension triggers message bus which re-establishes a
DB connection in `SiteSettingExtension#process_message`. That happens
concurrently and a test that requires a connection to the db will
fail when the reconnection is happening.
Before this patch, a high trust level user could flag something
and have an action be taken, as well as skipping the flag queue.
Now, if a TL3/TL4 cause an action, the flag will skip the minimum
visibility check and allow staff to review it.
This allows fidelity in controlling excerpt (text that shows up when you pin a topic or link to it externally):
```
I am some text
[excerpt]
This is some **custom** markdown that should be the excerpt
[/excerpt]
More text
```
Previous solution relied on DIVs, unfortunately DIVs do not play well,
by design with mixing markdown unless you have a preceding newline eg:
```
<div class='hello'>
this will be treated properly as markdown
</div>
```
This extra newline is not desirable.
I am also considering adding
```
[div class=excerpt]
[/div]
```
This would offer lots of flexibility to themes and plugins that do not want the extra annoying newline.
As per the documentation for KEYS
```
Warning: consider KEYS as a command that should only be used in production environments with extreme care. It may ruin performance when it is executed against large databases. This command is intended for debugging and special operations, such as changing your keyspace layout.
```
Instead SCAN
```
Since these commands allow for incremental iteration, returning only a small number of elements per call, they can be used in production without the downside of commands like KEYS or SMEMBERS that may block the server for a long time (even several seconds) when called against big collections of keys or elements.
```
This generates a 10x10 PNG thumbnail for each lightboxed image.
If Image Lazy Loading is enabled (IntersectionObserver API) then
we'll load the low res version when offscreen. As the image scrolls
in we'll swap it for the high res version.
We use a WeakMap to track the old image attributes. It's much less
memory than storing them as `data-*` attributes and swapping them
back and forth all the time.
`SiteSerializer#is_readonly` is cached for an anonymous user so we have
to clear the cache when disabling readonly mode. Otherwise, the site may
appear to be in readonly mode for an extended period of time.
Historically due to https://meta.discourse.org/t/why-is-discourse-so-slow-on-android/8823
we decreased page sizes of both home page and topic page on android by half.
This was done on the server side and as a side effect and caused page sizes on android
to mismatch between Android and non Android.
Unfortunately about a year ago googlebot started pretending it is Android,
this cause Google to start indexing pages as what android would see. So
it saw double the amount of pages in the index as what exists on desktop.
This in turn caused double the amount of indexing work and a large amount
of broken links on long topics.
This fix removes all special behavior which is no longer needed due to
other performance work in Discourse including raw handlebars on home page
and virtual dom on topic pages.
I tested we do not need this on Blu Advance 5.0 it has 1.3 GHZ mediatec mt6580
This phone retails for around $50 USD.
If we decide long term that we want any hacks like this we will shift them
to the client side. It can just hold data in memory without rendering.
Some URLs in browsers are non compliant and contain twos `#` this commit adds
special handling for this edge case by auto encoding any fragments containing `#`
