Re-check outgoing requests after processing them

... in case any new requests have been added during processing.
Fixes element-hq/element-web#30988

Author: andybalaam

spec/integ/crypto/cross-signing.spec.ts

@@ -403,7 +403,7 @@ describe("cross-signing", () => {
             const isCrossSigningReady = await aliceClient.getCrypto()!.isCrossSigningReady();
 
             expect(isCrossSigningReady).toBeFalsy();
-        });
+        }, 10000);
     });
 
     describe("getCrossSigningKeyId", () => {

spec/unit/rust-crypto/OutgoingRequestsManager.spec.ts

@@ -92,9 +92,11 @@ describe("OutgoingRequestsManager", () => {
             await secondRequest;
             await thirdRequest;
 
-            // outgoingRequests should be called twice in total, as the second and third requests are
-            // processed in the same loop.
-            expect(olmMachine.outgoingRequests).toHaveBeenCalledTimes(2);
+            // outgoingRequests should be called three times in total:
+            // 1. the first time,
+            // 2. the second and third requests processed in the same loop, and
+            // 3. checking that all requests are finished
+            expect(olmMachine.outgoingRequests).toHaveBeenCalledTimes(3);
 
             expect(processor.makeOutgoingRequest).toHaveBeenCalledTimes(3);
             expect(processor.makeOutgoingRequest).toHaveBeenCalledWith(request1);

src/rust-crypto/OutgoingRequestsManager.ts

@@ -139,5 +139,19 @@ export class OutgoingRequestsManager {
                 this.logger.error(`Failed to process outgoing request ${request.type}: ${e}`);
             }
         }
+
+        // If we handled any requests this time, more may have been queued as
+        // part of that handling, so do an extra check to make sure we handle
+        // them immediately. See
+        // https://github.com/element-hq/element-web/issues/30988
+        if (outgoingRequests.length > 0) {
+            // We call doProcessOutgoingRequests but since we expect that we are
+            // already processing outgoing requests, this call will not kick off
+            // the processing loop, but just set `nextLoopDeferred` and return,
+            // which will mean we loop one more time.
+            this.doProcessOutgoingRequests().catch((e) => {
+                this.logger.warn("processOutgoingRequests: Error re-checking outgoing requests", e);
+            });
+        }
     }
 }