Partial fix for #4389.
* Fix invalid username searches returning all posts instead of no posts.
* Fix "user:A user:B" returning results for user:B instead of no results.
* Fix "approver:A approver:B" returning results for approver:B instead of no results.
* Add support for negated -commenter, -noter, -noteupdater, -upvote, -downvote metatags.
* Add support for "any" and "none" values for all username metatags,
including negated metatags that didn't support "any" or "none" before.
* Change noter:any and commenter:any to include posts with deleted notes
or comments. Note that commenter:<username> already included deleted
comments before. This is so that commenter:any has the same behavior
as commenter:<username>
* Fix corrupted image detection. We were shelling out to vips and trying
to grep for error messages, but the error message for jpeg files changed.
Now we load the file in ruby vips, which raises an error on failure.
* Don't attempt to redownload corrupted images. If a download completes
without any errors yet the downloaded file is corrupt, then something is
wrong at the source and redownloading is unlikely to help. Let the
upload fail and the user retry if necessary.
* Validate that all uploads are uncorrupted, including files uploaded
from a computer, not just files uploaded from a source.
Fix table columns being collapsed to one character wide in certain
cases. Caused by setting `word-break: break-word` on div.prose, which
was needed to stop very long unbroken strings making columns too wide,
but has the opposite effect of making columns too narrow in other cases.
Example: https://danbooru.donmai.us/forum_topics/13868?page=28#forum_post_164950
When favoriting/unfavoriting a post, it would also be upvoted/"un"voted
but the upvote/downvote/undo vote buttons would stay shown/hidden as
they were before unlike when pressing those buttons.
For example when you want change from favorite to merely upvoted you
would have to reload the page in between.
* Make IP bans soft deletable.
* Add a hit counter to track how many times an IP ban has blocked someone.
* Add a last hit timestamp to track when the IP ban last blocked someone.
* Add a new type of IP ban, the signup ban. Signup bans restrict new
signups from editing anything until they've verified their email
address.
* Call them hidden tags instead of censored tags so that users don't
think that buying gold removes censorship from images (yes, this happened).
* Remove API ratelimit information (not relevant to most users).
Use validations instead of raising an exception when the password is
incorrect so that the controller can display errors sensibly.
Also fix users being logged out even when the deletion attempt failed
due to an incorrect password.
Remove the 10-try limit when there's a name conflict during renaming. We
forgot to increment the loop counter so this did nothing. This wasn't
necessary anyway since the loop will always terminate eventually because
names have finite length.
Name changes for deleted users are already visible to mods, so the only
thing we need to do here is to generate a name change before the user is
deleted.
* Let moderators see name changes for deleted users on the user name
change requests index and show pages. Before they could see name changes
for deleted users on user profiles, but not on the user name changes index.
* Let members see previous names on profile pages. Before they could see
previous names on the user name changes index, but not on profile pages
(ref: #4382).
* Allow tagging a post with a `disapproved:<disinterest|breaks_rules|poor_quality>` to disapprove it.
* Disallow disapproving active posts.
Fixes#4384.
