Define history_not_shared withheld code.

Co-authored-by: Kévin Commaille <76261501+zecakeh@users.noreply.github.com>

content/client-server-api/modules/end_to_end_encryption.md

@@ -1624,7 +1624,7 @@ Otherwise, before inviting Bob to a room, Alice's client constructs and sends a
    containing the sessions she is aware of in the room. Alice MUST include
    only [shareable encryption sessions](#shareable-encryption-sessions) in the
    `room_keys` section of the structure; other sessions SHOULD be listed in the
-   with `withheld` section.
+   `withheld` section.
 
 3. The client serialises the `RoomKeyBundle` as JSON.
 

data/api/client-server/definitions/room_key_bundle.yaml

@@ -41,6 +41,8 @@ properties:
           example: "m.megolm.v1.aes-sha2"
         room_id:
           type: string
+          format: mx-room-id
+          pattern: "^!"
           description: |-
             The room where the session is used.
           example: "!Cuyf34gef24t:localhost"
@@ -48,6 +50,7 @@ properties:
           type: object
           additionalProperties:
             type: string
+            format: mx-unpadded-base64
           description: |-
             A map from algorithm name (`ed25519`) to the Ed25519 signing key of
             the device which initiated the session originally, according to the
@@ -55,6 +58,7 @@ properties:
           example: { "ed25519": "aj40p+aw64yPIdsxoog8jhPu9i7l7NcFRecuOQblE3Y" }
         sender_key:
           type: string
+          format: mx-unpadded-base64
           description: |-
             Unpadded base64-encoded device Curve25519 key, of the device which
             initiated the session originally, according to the creator of this
@@ -67,9 +71,10 @@ properties:
           example: "X3lUlvLELLYxeTx4yOVu6UDpasGEVO0Jbu+QFnm0cKQ"
         session_key:
           type: string
+          format: mx-unpadded-base64
           description: |-
             Unpadded base64-encoded session key in [session-export
-            format](https://gitlab.matrix.org/matrix-org/olm/blob/master/docs/megolm.md#session-export-format).
+            format](/olm-megolm/megolm/#session-export-format).
           example: "AgAAAADxKHa9uFxcXzwYoNueL5Xqi69IkD4sni8Llf..."
     required:
       - algorithm

data/event-schemas/schema/components/room_key_withheld_content.yaml

@@ -7,6 +7,8 @@ properties:
       The encryption algorithm for the key that this event is about.
   room_id:
     type: string
+    format: mx-room-id
+    pattern: "^!"
     description: |-
       Required if `code` is not `m.no_olm`.  The room for the key that
       this event is about.
@@ -17,6 +19,7 @@ properties:
       that this event is about.
   sender_key:
     type: string
+    format: mx-unpadded-base64
     description: |-
       The unpadded base64-encoded device curve25519 key of the event\'s
       sender.
@@ -28,6 +31,7 @@ properties:
       - m.unauthorised
       - m.unavailable
       - m.no_olm
+      - m.history_not_shared
     description: |-
       A machine-readable code for why the key was not sent. Codes beginning
       with `m.` are reserved for codes defined in the Matrix

data/event-schemas/schema/m.room_key.withheld.yaml

@@ -8,7 +8,7 @@ description: |-
   This event type is used to indicate that the sender is not sharing room keys
   with the recipient. It is sent as a to-device event.
 
-  Possible values for `code` include:
+  The following values for `code` are defined:
 
   * `m.blacklisted`: the user/device was blacklisted.
   * `m.unverified`: the user/device was not verified, and the sender is only
@@ -19,6 +19,13 @@ description: |-
   * `m.unavailable`: sent in reply to a key request if the device that the
     key is requested from does not have the requested key.
   * `m.no_olm`: an olm session could not be established.
+  * **[Added in `v1.19`]** `m.history_not_shared`: when used as part of a
+    [`RoomKeyBundle` structure](/client-server-api/#definition-roomkeybundle),
+    indicates to the recipient of the bundle that the corresponding room key
+    was not marked as
+    [shareable](/client-server-api/#shareable-encryption-sessions) by the
+    sender. Clients SHOULD NOT use this `code` in a `m.room_key.withheld`
+    event.
 
   In most cases, this event refers to a specific room key. The one exception to
   this is when the sender is unable to establish an olm session with the

data/event-schemas/schema/m.room_key_bundle.yaml

@@ -21,6 +21,8 @@ properties:
     properties:
       room_id:
         type: string
+        format: mx-room-id
+        pattern: "^!"
         description: The room to which the keys in the key bundle relate.
       file:
         description: |-