Why:
* Naming conflicts may arise on autocreation.
* For example, when generating temporary user names, the config
wgAutoCreateTempUser['serialMapping']['type'] determines how
the unique, numerical part of the name is generated, and naming
conflicts may arise when changing types.
* Specifically we encountered the case of changing the
$wgAutoCreateTempUser['serialMapping']['type'] from 'scramble'
to 'plain-numeric'.
* In general conflict could be avoided in 'plain-numeric' mode if
the highest number used in an existing username is known, by
adding an offset.
What:
* Handle an 'offset' config option in PlainNumericSerialMapping to
allow avoiding conflicts.
Bug: T353545
Change-Id: Id2f9a5b5cc808ce859b93b597cf7ea0efcd9e269
Add services and utilities for automatic creation of temporary user
accounts on page save, in order to avoid exposing the user's IP
address.
* Add $wgAutoCreateTempUser, for configuring the system
* Add TempUserConfig service, which interprets the config.
* Add TempUserCreator service, which creates users during page save as
requested by EditPage. With proxy methods to TempUserConfig for
convenience.
* Add table user_autocreate_serial. Table creation is necessary before
the feature is enabled but is not necessary before deployment of this
commit.
Bug: T300263
Change-Id: Ib14a352490fc42039106523118e8d021844e3dfb
