Remove `worker_replication_*` deprecated settings, with helpful errors on startup (#15860)

Co-authored-by: reivilibre <oliverw@matrix.org>

3 files changed, 15 insertions, 48 deletions

diff --git a/docs/upgrade.md b/docs/upgrade.md
index 384f4010b4..b94d13c4da 100644
--- a/docs/upgrade.md
+++ b/docs/upgrade.md
@@ -98,6 +98,21 @@ You will need Python 3.8 to run Synapse v1.88.0 (due out July 18th, 2023).
 If you use current versions of the Matrix.org-distributed Debian
 packages or Docker images, no action is required.
 
+## Removal of `worker_replication_*` settings
+
+As mentioned previously in [Upgrading to v1.84.0](#upgrading-to-v1840), the following deprecated settings
+are being removed in this release of Synapse:
+
+* [`worker_replication_host`](https://matrix-org.github.io/synapse/v1.86/usage/configuration/config_documentation.html#worker_replication_host)
+* [`worker_replication_http_port`](https://matrix-org.github.io/synapse/v1.86/usage/configuration/config_documentation.html#worker_replication_http_port)
+* [`worker_replication_http_tls`](https://matrix-org.github.io/synapse/v1.86/usage/configuration/config_documentation.html#worker_replication_http_tls)
+
+Please ensure that you have migrated to using `main` on your shared configuration's `instance_map`
+(or create one if necessary). This is required if you have ***any*** workers at all;
+administrators of single-process (monolith) installations don't need to do anything.
+
+For an illustrative example, please see [Upgrading to v1.84.0](#upgrading-to-v1840) below.
+
 
 # Upgrading to v1.86.0
 
diff --git a/docs/usage/configuration/config_documentation.md b/docs/usage/configuration/config_documentation.md
index 89a92c4682..04e8390ffe 100644
--- a/docs/usage/configuration/config_documentation.md
+++ b/docs/usage/configuration/config_documentation.md
@@ -4107,51 +4107,6 @@ Example configuration:
 worker_name: generic_worker1
 ```
 ---
-### `worker_replication_host`
-*Deprecated as of version 1.84.0. Place `host` under `main` entry on the [`instance_map`](#instance_map) in your shared yaml configuration instead.*
-
-The HTTP replication endpoint that it should talk to on the main Synapse process.
-The main Synapse process defines this with a `replication` resource in
-[`listeners` option](#listeners).
-
-Example configuration:
-```yaml
-worker_replication_host: 127.0.0.1
-```
----
-### `worker_replication_http_port`
-*Deprecated as of version 1.84.0. Place `port` under `main` entry on the [`instance_map`](#instance_map) in your shared yaml configuration instead.*
-
-The HTTP replication port that it should talk to on the main Synapse process.
-The main Synapse process defines this with a `replication` resource in
-[`listeners` option](#listeners).
-
-Example configuration:
-```yaml
-worker_replication_http_port: 9093
-```
----
-### `worker_replication_http_tls`
-*Deprecated as of version 1.84.0. Place `tls` under `main` entry on the [`instance_map`](#instance_map) in your shared yaml configuration instead.*
-
-Whether TLS should be used for talking to the HTTP replication port on the main
-Synapse process.
-The main Synapse process defines this with the `tls` option on its [listener](#listeners) that
-has the `replication` resource enabled.
-
-**Please note:** by default, it is not safe to expose replication ports to the
-public Internet, even with TLS enabled.
-See [`worker_replication_secret`](#worker_replication_secret).
-
-Defaults to `false`.
-
-*Added in Synapse 1.72.0.*
-
-Example configuration:
-```yaml
-worker_replication_http_tls: true
-```
----
 ### `worker_listeners`
 
 A worker can handle HTTP requests. To do so, a `worker_listeners` option
diff --git a/docs/workers.md b/docs/workers.md
index 303e0f0e7a..03415c6eb3 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -145,9 +145,6 @@ In the config file for each worker, you must specify:
    with an `http` listener.
  * **Synapse 1.72 and older:** if handling the `^/_matrix/client/v3/keys/upload` endpoint, the HTTP URI for
    the main process (`worker_main_http_uri`). This config option is no longer required and is ignored when running Synapse 1.73 and newer.
- * **Synapse 1.83 and older:** The HTTP replication endpoint that the worker should talk to on the main synapse process
-   ([`worker_replication_host`](usage/configuration/config_documentation.md#worker_replication_host) and
-   [`worker_replication_http_port`](usage/configuration/config_documentation.md#worker_replication_http_port)). If using Synapse 1.84 and newer, these are not needed if `main` is defined on the [shared configuration](#shared-configuration) `instance_map`
 
 For example: