problem: chain backed by single grpc upstream is unavailable

src/main/kotlin/io/emeraldpay/dshackle/upstream/CurrentUpstreams.kt

@@ -58,6 +58,9 @@ class CurrentUpstreams(
                 } else {
                     current.addUpstream(up)
                 }
+                if (!callTargets.containsKey(chain)) {
+                    setupDefaultMethods(chain)
+                }
                 log.info("Upstream ${change.upstream.getId()} with chain $chain has been added")
             }
         }
@@ -84,12 +87,13 @@ class CurrentUpstreams(
     }
 
     override fun getDefaultMethods(chain: Chain): CallMethods {
-        var current = callTargets[chain]
+        return callTargets[chain] ?: return setupDefaultMethods(chain)
-        if (current == null) {
+    }
-            current = QuorumBasedMethods(objectMapper, chain)
+
-            callTargets[chain] = current
+    fun setupDefaultMethods(chain: Chain): QuorumBasedMethods {
-        }
+        val created = QuorumBasedMethods(objectMapper, chain)
-        return current
+        callTargets[chain] = created
+        return created
     }
 
     override fun isAvailable(chain: Chain): Boolean {

src/test/groovy/io/emeraldpay/dshackle/upstream/CurrentUpstreamsSpec.groovy

@@ -52,4 +52,22 @@ class CurrentUpstreamsSpec extends Specification {
         current.getUpstream(Chain.ETHEREUM).getAll().toSet() == [up3].toSet()
         current.getUpstream(Chain.ETHEREUM_CLASSIC).getAll().toSet() == [up2].toSet()
     }
+
+    def "available after adding"() {
+        setup:
+        def current = new CurrentUpstreams(TestingCommons.objectMapper())
+        def up1 = new EthereumUpstreamMock("test1", Chain.ETHEREUM, TestingCommons.api(Stub(ReactorRpcClient)))
+
+        when:
+        def act = current.isAvailable(Chain.ETHEREUM)
+        then:
+        !act
+
+        when:
+        current.update(new UpstreamChange(Chain.ETHEREUM, up1, UpstreamChange.ChangeType.ADDED))
+        act = current.isAvailable(Chain.ETHEREUM)
+
+        then:
+        act
+    }
 }