fix: don't activate unsupported pairs with peers

This ensures that, even when not running in strict mode, we only
activate trading pairs with peers when we support both currencies of the
pair and the trading pair itself locally. Previously we would activate
every trading pair, like BTC/LTC when we don't have a swap client for
LTC, resulting in us requesting and receiving order updates for trading
pairs that are irrelevent to us.

Author: sangaman

Diff for: lib/orderbook/OrderBook.ts

@@ -994,6 +994,11 @@ class OrderBook extends EventEmitter {
       if (peer.isPairActive(pairId)) {
         return false; // don't verify a pair that is already active
       }
+      if (!this.tradingPairs.has(pairId)) {
+        // if we don't support the trading pair locally, then we don't want to verify or activate it
+        return false;
+      }
+
       const [baseCurrency, quoteCurrency] = pairId.split('/');
       const peerCurrenciesEnabled = !peer.disabledCurrencies.has(baseCurrency)
         && !peer.disabledCurrencies.has(quoteCurrency);
@@ -1050,7 +1055,9 @@ class OrderBook extends EventEmitter {
 
     // activate verified currencies
     currenciesToVerify.forEach((swappable, currency) => {
-      if (swappable || !this.strict) { // always activate currencies if not in strict mode
+      // in strict mode, we only activate "swappable" currencies where a route to peer is possible or a sanity swap has completed
+      // in non-strict mode, we activate any currency which we also support locally
+      if (swappable || (!this.strict && this.swaps.swapClientManager.has(currency))) {
         peer.activateCurrency(currency);
       }
     });

Diff for: lib/swaps/SwapClientManager.ts

@@ -247,6 +247,15 @@ class SwapClientManager extends EventEmitter {
     return this.swapClients.get(currency);
   }
 
+  /**
+   * Returns whether the swap client manager has a client for a given currency.
+   * @param currency the currency that the swap client is linked to.
+   * @returns `true` if a swap client exists, false otherwise.
+   */
+  public has = (currency: string): boolean => {
+    return this.swapClients.has(currency);
+  }
+
   /** Gets the type of swap client for a given currency. */
   public getType = (currency: string) => {
     return this.swapClients.get(currency)?.type;

Diff for: test/jest/Orderbook.spec.ts

@@ -175,13 +175,11 @@ describe('OrderBook', () => {
   test('nosanityswaps enabled adds pairs and requests orders', async () => {
     orderbook['nosanityswaps'] = true;
     await orderbook['verifyPeerPairs'](peer);
-    expect(mockActivateCurrency).toHaveBeenCalledTimes(3);
+    expect(mockActivateCurrency).toHaveBeenCalledTimes(2);
     expect(mockActivateCurrency).toHaveBeenCalledWith('BTC');
     expect(mockActivateCurrency).toHaveBeenCalledWith('LTC');
-    expect(mockActivateCurrency).toHaveBeenCalledWith('WETH');
-    expect(mockActivatePair).toHaveBeenCalledTimes(2);
+    expect(mockActivatePair).toHaveBeenCalledTimes(1);
     expect(mockActivatePair).toHaveBeenCalledWith(advertisedPairs[0]);
-    expect(mockActivatePair).toHaveBeenCalledWith(advertisedPairs[1]);
   });
 
   test('isPeerCurrencySupported returns true for a known currency with matching identifiers', async () => {