# Which Problems Are Solved
Some OAuth2 and OIDC providers require the use of PKCE for all their
clients. While ZITADEL already recommended the same for its clients, it
did not yet support the option on the IdP configuration.
# How the Problems Are Solved
- A new boolean `use_pkce` is added to the add/update generic OAuth/OIDC
endpoints.
- A new checkbox is added to the generic OAuth and OIDC provider
templates.
- The `rp.WithPKCE` option is added to the provider if the use of PKCE
has been set.
- The `rp.WithCodeChallenge` and `rp.WithCodeVerifier` options are added
to the OIDC/Auth BeginAuth and CodeExchange function.
- Store verifier or any other persistent argument in the intent or auth
request.
- Create corresponding session object before creating the intent, to be
able to store the information.
- (refactored session structs to use a constructor for unified creation
and better overview of actual usage)
Here's a screenshot showing the URI including the PKCE params:

# Additional Changes
None.
# Additional Context
- Closes#6449
- This PR replaces the existing PR (#8228) of @doncicuto. The base he
did was cherry picked. Thank you very much for that!
---------
Co-authored-by: Miguel Cabrerizo <doncicuto@gmail.com>
Co-authored-by: Stefan Benz <46600784+stebenz@users.noreply.github.com>
Even though this is a feature it's released as fix so that we can back port to earlier revisions.
As reported by multiple users startup of ZITADEL after leaded to downtime and worst case rollbacks to the previously deployed version.
The problem starts rising when there are too many events to process after the start of ZITADEL. The root cause are changes on projections (database tables) which must be recomputed. This PR solves this problem by adding a new step to the setup phase which prefills the projections. The step can be enabled by adding the `--init-projections`-flag to `setup`, `start-from-init` and `start-from-setup`. Setting this flag results in potentially longer duration of the setup phase but reduces the risk of the problems mentioned in the paragraph above.
This implementation increases parallel write capabilities of the eventstore.
Please have a look at the technical advisories: [05](https://zitadel.com/docs/support/advisory/a10005) and [06](https://zitadel.com/docs/support/advisory/a10006).
The implementation of eventstore.push is rewritten and stored events are migrated to a new table `eventstore.events2`.
If you are using cockroach: make sure that the database user of ZITADEL has `VIEWACTIVITY` grant. This is used to query events.
* fix: handling of ldap login through separate endpoint
* fix: handling of ldap login through separate endpoint
* fix: handling of ldap login through separate endpoint
* fix: successful intent for ldap
* fix: successful intent for ldap
* fix: successful intent for ldap
* fix: add changes from code review
* fix: remove set intent credentials and handle ldap errors
* fix: remove set intent credentials and handle ldap errors
* refactor into separate methods and fix merge
* remove mocks
---------
Co-authored-by: Livio Spring <livio.a@gmail.com>