**## Problem**
`Special:SetAliases`, `Special:NewItem` and `Special:NewProperty` need to be updated as well page does not allow the user to enter an alias that contains a `|` character in it's text. This is because the current page has only one fieldose pages provide one field to enter aliases that instructs the user to enter the listall of aliasesthem, and split themseparated with a `|` character.
Since a `|` character might have legitimate use-cases, being part of the alias text, such as in the following:
* https://www.wikidata.org/wiki/Q1161179 "Mac|Life"
* https://www.wikidata.org/wiki/Q1753348 "M|A|R|R|S"
we have to find a way to allow the user to use `|`s in aliases when they edit them through `Special:SetAliases`, `Special:NewItem` and `Special:NewProperty` pages.
**Suggested## Solutions**
* make `Special:SetAliases` fail when there's already one or more alias on the item that contain a `|`. This can be done anyway as first iteration, then followed up by one of the following.
* provide the user with a sensible way to continue splitting aliases using `|`s, but to escape those that must be part of the alias text.### Iteration 1 Acceptance Criteria
* `Special:SetAliases`, (for example`Special:NewItem` and `Special:NewProperty` pages redirects to the item/property page and instructs the user (with a warning) that there's already one or more alias on the item that contain a `|`, and that they can escape a pipe by a pipe `||` or a backslash `\|`)will have to edit the item/property on their page in order to be able to set aliases with |s in them.
* use the TagMultiselectWidget from OOUI: https://doc.wikimedia.org/oojs-ui/master/demos/?page=widgets&theme=wikimediaui&direction=ltr&platform=desktop -- a data point is collected on how many times this failure happens (only count per week/monght is enough) to understand the size of the issue and impact of the solution
This iteration is taken as a first step to eliminate the unintended wrong aliases being set on items/properties, and to collect enough data to know how big the problem is. Given that T118065 was created in 2015 and never been addressed, it could be that there's still no enough usage of those pages in combination with this case to justify costs of later iterations yet.
-----
// the next iteration can be either done as an A/B test or one alternative is selected to be implemented, that's decided depending on learnings from prev. (note: that does not work without JavaScript)iteration//
### Iteration 2.A Acceptance Criteria
* add a new special page `Special:AddAlias` that adds one alias at a time (can have "add another" checkbox to redirect to it again).on `Special:SetAliases`, `Special:NewItem` and `Special:NewProperty` pages, in alaises field, the user can continue to split aliases using `|`s, and can also escape those that must be part of the alias text by prefixing them with another pipe `||`.
### Iteration 2.B Acceptance Criteria
**Notes*** **without javascript** provide the user a way to reload the page with as many aliases fields to fill in one-by-one as they need
- related old problem T118065* **with javascript** use the [[ https://doc.wikimedia.org/oojs-ui/master/demos/?page=widgets&theme=wikimediaui&direction=ltr&platform=desktop | TagMultiselectWidget from OOUI ]]
- `Special:NewItem` and `Special:NewProperty` need to be updated as well