RPC fee command checks open ledger rules (RIPD-1183):

* Matches internal getMetric() to avoid races.

src/ripple/app/misc/impl/TxQ.cpp

@@ -1151,6 +1151,7 @@ TxQ::doRPC(Application& app) const
 
     auto const view = app.openLedger().current();
     auto const metrics = getMetrics(app, *view);
+    assert(metrics);
     if (!metrics)
         return{};
 

src/ripple/app/tests/TxQ_test.cpp

@@ -25,6 +25,7 @@
 #include <ripple/basics/Log.h>
 #include <ripple/basics/mulDiv.h>
 #include <ripple/basics/TestSuite.h>
+#include <ripple/protocol/ErrorCodes.h>
 #include <ripple/protocol/Feature.h>
 #include <ripple/protocol/JsonFields.h>
 #include <ripple/protocol/STTx.h>
@@ -1529,6 +1530,42 @@ public:
         }
     }
 
+    void testRPC()
+    {
+        using namespace jtx;
+        {
+            Env env(*this, features(featureFeeEscalation));
+
+            auto fee = env.rpc("fee");
+
+            if (expect(fee.isMember(jss::result) &&
+                !RPC::contains_error(fee[jss::result])))
+            {
+                auto const& result = fee[jss::result];
+                expect(result.isMember(jss::drops));
+                expect(result.isMember(jss::levels));
+                expect(result.isMember(jss::current_ledger_size));
+                expect(result.isMember(jss::current_queue_size));
+                expect(result.isMember(jss::expected_ledger_size));
+            }
+        }
+
+        {
+            Env env(*this);
+
+            auto fee = env.rpc("fee");
+
+            if(expect(fee.isMember(jss::result) &&
+                RPC::contains_error(fee[jss::result])))
+            {
+                auto const& result = fee[jss::result];
+                expect(result.isMember(jss::error) &&
+                    result[jss::error] ==
+                        RPC::get_error_info(rpcNOT_ENABLED).token);
+            }
+        }
+    }
+
     void run()
     {
         testQueue();
@@ -1546,6 +1583,7 @@ public:
         testBlockers();
         testInFlightBalance();
         testConsequences();
+        testRPC();
     }
 };
 

src/ripple/rpc/handlers/Fee1.cpp

@@ -18,8 +18,9 @@
 //==============================================================================
 
 #include <BeastConfig.h>
+#include <ripple/app/ledger/OpenLedger.h>
+#include <ripple/app/main/Application.h>
 #include <ripple/app/misc/TxQ.h>
-#include <ripple/app/ledger/LedgerMaster.h>
 #include <ripple/rpc/Context.h>
 #include <ripple/protocol/ErrorCodes.h>
 #include <ripple/protocol/Feature.h>
@@ -29,13 +30,19 @@ namespace ripple
     Json::Value doFee(RPC::Context& context)
     {
         // Bail if fee escalation is not enabled.
-        if (!context.app.getLedgerMaster().getValidatedRules().
-            enabled(featureFeeEscalation, context.app.config().features))
+        auto const view = context.app.openLedger().current();
+        if (!view || !view->rules().enabled(
+            featureFeeEscalation, context.app.config().features))
         {
             RPC::inject_error(rpcNOT_ENABLED, context.params);
             return context.params;
         }
 
-        return context.app.getTxQ().doRPC(context.app);
+        auto result = context.app.getTxQ().doRPC(context.app);
+        if (result.type() == Json::objectValue)
+            return result;
+        assert(false);
+        RPC::inject_error(rpcINTERNAL, context.params);
+        return context.params;
     }
 } // ripple