Support rewriting push rules when our internal defaults change

and change our internal default for tombstones

src/base-apis.js

@@ -29,6 +29,7 @@ import logger from './logger';
 
 const httpApi = require("./http-api");
 const utils = require("./utils");
+const PushProcessor = require("./pushprocessor");
 
 function termsUrlForService(serviceType, baseUrl) {
     switch (serviceType) {
@@ -1477,7 +1478,9 @@ MatrixBaseApis.prototype.setPusher = function(pusher, callback) {
  * @return {module:http-api.MatrixError} Rejects: with an error response.
  */
 MatrixBaseApis.prototype.getPushRules = function(callback) {
-    return this._http.authedRequest(callback, "GET", "/pushrules/");
+    return this._http.authedRequest(callback, "GET", "/pushrules/").then(rules => {
+        return PushProcessor.rewriteDefaultRules(rules);
+    });
 };
 
 /**

src/pushprocessor.js

@@ -43,6 +43,11 @@ const DEFAULT_OVERRIDE_RULES = [
                 key: "type",
                 pattern: "m.room.tombstone",
             },
+            {
+                kind: "event_match",
+                key: "state_key",
+                pattern: "",
+            }
         ],
         actions: [
             "notify",
@@ -455,6 +460,32 @@ PushProcessor.actionListToActionsObject = function(actionlist) {
     return actionobj;
 };
 
+/**
+ * Rewrites conditions on a client's push rules to match the defaults
+ * where applicable. Useful for upgrading push rules to more strict
+ * conditions when the server is falling behind on defaults.
+ * @param {object} incomingRules The client's existing push rules
+ * @returns {object} The rewritten rules
+ */
+PushProcessor.rewriteDefaultRules = function(incomingRules) {
+    const newRules = JSON.parse(JSON.stringify(incomingRules)); // deep clone
+
+    // Fix default override rules
+    newRules.global.override = newRules.global.override.map(r => {
+        const defaultRule = DEFAULT_OVERRIDE_RULES.find(d => d.rule_id === r.rule_id);
+        if (!defaultRule) return r;
+
+        // Copy over the actions, default, and conditions. Don't touch the user's
+        // preference.
+        r.default = defaultRule.default;
+        r.conditions = defaultRule.conditions;
+        r.actions = defaultRule.actions;
+        return r;
+    });
+
+    return newRules;
+};
+
 /**
  * @typedef {Object} PushAction
  * @type {Object}

src/sync.js

@@ -32,6 +32,7 @@ const Group = require('./models/group');
 const utils = require("./utils");
 const Filter = require("./filter");
 const EventTimeline = require("./models/event-timeline");
+const PushProcessor = require("./pushprocessor");
 import logger from '../src/logger';
 
 import {InvalidStoreError} from './errors';
@@ -1030,8 +1031,9 @@ SyncApi.prototype._processSyncResponse = async function(
                 // honour push rules that were previously cached. Base rules
                 // will be updated when we recieve push rules via getPushRules
                 // (see SyncApi.prototype.sync) before syncing over the network.
-                if (accountDataEvent.getType() == 'm.push_rules') {
-                    client.pushRules = accountDataEvent.getContent();
+                if (accountDataEvent.getType() === 'm.push_rules') {
+                    const rules = accountDataEvent.getContent();
+                    client.pushRules = PushProcessor.rewriteDefaultRules(rules);
                 }
                 client.emit("accountData", accountDataEvent);
                 return accountDataEvent;