Files
projectsend/app/Support/VacatedSlug.php
ignacionelson 98597d462d Give a deleted folder's name back
Delete a folder called Test and you could never have a folder called Test
again. The deletion worked, the folder left the screen, and the name went
with it — permanently, with an error that named a collision against a row
the interface will not show you and offered nothing to do about it.

Files and groups had it too. All three carry a unique index on slug and
all three soft-delete, so the trashed row sat in the index holding a name
nothing could reach. A public one failed outright at the validator, which
checks the table and therefore sees rows the screen does not. A private
one failed more quietly: the derived slug stepped around the trashed row
into report-2, then report-3, once per deletion, climbing forever.

The reservation was deliberate — a trashed row's slug was kept so that
restoring it could not land on somebody else's URL. But nothing in this
application restores anything. There is no restore() call, no route, no
screen; File's own comment says as much. Soft deletes are here so rows can
outlive their delete for foreign keys, the activity log and the erasure
grace period, never so they can come back. The slug was being held for a
page that could not return, and route binding already 404s the trashed row
in the meantime.

So deleting now hands the slug back, and the database is what makes that a
rewrite rather than a gentler lookup: teaching the collision checks to skip
trashed rows would leave two rows holding "report", which the unique index
rejects whatever the application thinks. The slug moves to report__deleted-42
instead. Underscores are the whole trick — Str::slug() turns them into
hyphens and Rules::slug() refuses them outright, so no derived slug and no
hand-typed one can ever land on a vacated one. That is a guarantee about
the character class rather than a hope about collisions.

The format lives in VacatedSlug rather than on the trait because the
migration needs it too and a trait constant cannot be reached through the
trait's own name — the first version of this was a fatal error waiting for
whoever ran migrations. The migration matters as much as the hook: without
it the fix only helps installations that have never deleted anything, and
every name already buried stays buried.

The collision checks still count trashed rows. It costs nothing and keeps
them honest about what the index will accept if a row is ever soft-deleted
by something that bypasses model events.

previous_file_id had this same bug and was fixed this same way, in
File::detachOnDelete — a trashed row holding its predecessor's unique slot
so the chain could never be re-linked. This is that fix, for the other four
unique indexes' worth of the same mistake. users.email is the one left, and
is deliberately not in here: an email address is a login identity rather
than a URL handle, and freeing it silently is the wrong answer.

Fixes #1645

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-18 12:11:02 -03:00

56 lines
1.6 KiB
PHP

<?php
declare(strict_types=1);
namespace App\Support;
use App\Support\Concerns\HasUniqueSlug;
/**
* The slug a deleted row holds, so the name it used to have goes back into
* circulation.
*
* Lives here rather than on HasUniqueSlug because the migration that vacates
* slugs deleted before the behaviour existed needs the identical format, and
* a trait constant cannot be reached through the trait's own name. Two copies
* of this format that drift apart would leave rows the application no longer
* recognises as vacated, so there is one.
*
* @see HasUniqueSlug
*/
final class VacatedSlug
{
/**
* Underscores are the whole trick: Str::slug() turns them into hyphens and
* Rules::slug() refuses them outright, so no derived slug and no
* hand-typed one can ever collide with a vacated one.
*/
public const MARKER = '__deleted-';
/**
* Column width. Slugs are ASCII by construction, but the truncation is
* done in characters so a hand-written row cannot cut a byte in half.
*/
private const MAX_LENGTH = 255;
/**
* @param int|string $key the row's own id, so two deleted rows that
* shared a name do not collide with each other
*/
public static function for(string $slug, int|string $key): string
{
if (self::isVacated($slug)) {
return $slug;
}
$suffix = self::MARKER.$key;
return mb_substr($slug, 0, self::MAX_LENGTH - mb_strlen($suffix)).$suffix;
}
public static function isVacated(string $slug): bool
{
return str_contains($slug, self::MARKER);
}
}