Implement MSC3966: a push rule condition to check if an array contains a value (#3180)

* Support MSC3966 to match values in an array in push rule conditions.

* Update to stable identifiers.

* Appease the linter.

spec/unit/pushprocessor.spec.ts

@@ -576,6 +576,75 @@ describe("NotificationService", function () {
         });
     });
 
+    describe("Test event property contains", () => {
+        it.each([
+            // Simple string matching.
+            { value: "bar", eventValue: ["bar"], expected: true },
+            // Matches are case-sensitive.
+            { value: "bar", eventValue: ["BAR"], expected: false },
+            // Values should not be type-coerced.
+            { value: "bar", eventValue: [true], expected: false },
+            { value: "bar", eventValue: [1], expected: false },
+            { value: "bar", eventValue: [false], expected: false },
+            // Boolean matching.
+            { value: true, eventValue: [true], expected: true },
+            { value: false, eventValue: [false], expected: true },
+            // Types should not be coerced.
+            { value: true, eventValue: ["true"], expected: false },
+            { value: true, eventValue: [1], expected: false },
+            { value: false, eventValue: [null], expected: false },
+            // Null matching.
+            { value: null, eventValue: [null], expected: true },
+            // Types should not be coerced
+            { value: null, eventValue: [false], expected: false },
+            { value: null, eventValue: [0], expected: false },
+            { value: null, eventValue: [""], expected: false },
+            { value: null, eventValue: [undefined], expected: false },
+            // Non-array or empty values should never be matched.
+            { value: "bar", eventValue: "bar", expected: false },
+            { value: "bar", eventValue: { bar: true }, expected: false },
+            { value: true, eventValue: { true: true }, expected: false },
+            { value: true, eventValue: true, expected: false },
+            { value: null, eventValue: [], expected: false },
+            { value: null, eventValue: {}, expected: false },
+            { value: null, eventValue: null, expected: false },
+            { value: null, eventValue: undefined, expected: false },
+        ])("test $value against $eventValue", ({ value, eventValue, expected }) => {
+            matrixClient.pushRules! = {
+                global: {
+                    override: [
+                        {
+                            actions: [PushRuleActionName.Notify],
+                            conditions: [
+                                {
+                                    kind: ConditionKind.EventPropertyContains,
+                                    key: "content.foo",
+                                    value: value,
+                                },
+                            ],
+                            default: true,
+                            enabled: true,
+                            rule_id: ".m.rule.test",
+                        },
+                    ],
+                },
+            };
+
+            testEvent = utils.mkEvent({
+                type: "m.room.message",
+                room: testRoomId,
+                user: "@alfred:localhost",
+                event: true,
+                content: {
+                    foo: eventValue,
+                },
+            });
+
+            const actions = pushProcessor.actionsForEvent(testEvent);
+            expect(actions?.notify).toBe(expected ? true : undefined);
+        });
+    });
+
     it.each([
         // The properly escaped key works.
         { key: "content.m\\.test.foo", pattern: "bar", expected: true },

src/@types/PushRules.ts

@@ -63,6 +63,7 @@ export function isDmMemberCountCondition(condition: AnyMemberCountCondition): bo
 export enum ConditionKind {
     EventMatch = "event_match",
     EventPropertyIs = "event_property_is",
+    EventPropertyContains = "event_property_contains",
     ContainsDisplayName = "contains_display_name",
     RoomMemberCount = "room_member_count",
     SenderNotificationPermission = "sender_notification_permission",
@@ -88,6 +89,11 @@ export interface IEventPropertyIsCondition extends IPushRuleCondition<ConditionK
     value: string | boolean | null | number;
 }
 
+export interface IEventPropertyContainsCondition extends IPushRuleCondition<ConditionKind.EventPropertyContains> {
+    key: string;
+    value: string | boolean | null | number;
+}
+
 export interface IContainsDisplayNameCondition extends IPushRuleCondition<ConditionKind.ContainsDisplayName> {
     // no additional fields
 }
@@ -114,6 +120,7 @@ export interface ICallStartedPrefixCondition extends IPushRuleCondition<Conditio
 export type PushRuleCondition =
     | IEventMatchCondition
     | IEventPropertyIsCondition
+    | IEventPropertyContainsCondition
     | IContainsDisplayNameCondition
     | IRoomMemberCountCondition
     | ISenderNotificationPermissionCondition

src/pushprocessor.ts

@@ -26,6 +26,7 @@ import {
     IContainsDisplayNameCondition,
     IEventMatchCondition,
     IEventPropertyIsCondition,
+    IEventPropertyContainsCondition,
     IPushRule,
     IPushRules,
     IRoomMemberCountCondition,
@@ -340,6 +341,8 @@ export class PushProcessor {
                 return this.eventFulfillsEventMatchCondition(cond, ev);
             case ConditionKind.EventPropertyIs:
                 return this.eventFulfillsEventPropertyIsCondition(cond, ev);
+            case ConditionKind.EventPropertyContains:
+                return this.eventFulfillsEventPropertyContains(cond, ev);
             case ConditionKind.ContainsDisplayName:
                 return this.eventFulfillsDisplayNameCondition(cond, ev);
             case ConditionKind.RoomMemberCount:
@@ -488,6 +491,24 @@ export class PushProcessor {
         return cond.value === this.valueForDottedKey(cond.key, ev);
     }
 
+    /**
+     * Check whether the given event matches the push rule condition by fetching
+     * the property from the event and comparing exactly against the condition's
+     * value.
+     * @param cond - The push rule condition to check for a match.
+     * @param ev - The event to check for a match.
+     */
+    private eventFulfillsEventPropertyContains(cond: IEventPropertyContainsCondition, ev: MatrixEvent): boolean {
+        if (!cond.key || cond.value === undefined) {
+            return false;
+        }
+        const val = this.valueForDottedKey(cond.key, ev);
+        if (!Array.isArray(val)) {
+            return false;
+        }
+        return val.includes(cond.value);
+    }
+
     private eventFulfillsCallStartedCondition(
         _cond: ICallStartedCondition | ICallStartedPrefixCondition,
         ev: MatrixEvent,