Improve handling of RPC ledger_index argument:

Some RPC commands return `ledger_index` as a quoted numeric
string. This change allows the returned value to be directly
copied and used for follow-on RPC commands.

This commit fixes #3533

src/ripple/json/json_value.h

@@ -136,7 +136,7 @@ operator!=(StaticString x, std::string const& y)
  * The sequence of an #arrayValue will be automatically resize and initialized
  * with #nullValue. resize() can be used to enlarge or truncate an #arrayValue.
  *
- * The get() methods can be used to obtanis default value in the case the
+ * The get() methods can be used to obtain a default value in the case the
  * required element does not exist.
  *
  * It is possible to iterate over the list of a #objectValue values using

src/ripple/rpc/impl/RPCHelpers.cpp

@@ -228,31 +228,23 @@ ledgerFromRequest(T& ledger, JsonContext& context)
             return {rpcINVALID_PARAMS, "ledgerHashMalformed"};
         return getLedger(ledger, ledgerHash, context);
     }
-    else if (indexValue.isNumeric())
-    {
-        return getLedger(ledger, indexValue.asInt(), context);
-    }
-    else
-    {
-        auto const index = indexValue.asString();
-        if (index == "validated")
-        {
-            return getLedger(ledger, LedgerShortcut::VALIDATED, context);
-        }
-        else
-        {
-            if (index.empty() || index == "current")
-                return getLedger(ledger, LedgerShortcut::CURRENT, context);
-            else if (index == "closed")
-                return getLedger(ledger, LedgerShortcut::CLOSED, context);
-            else
-            {
-                return {rpcINVALID_PARAMS, "ledgerIndexMalformed"};
-            }
-        }
-    }
 
-    return Status::OK;
+    auto const index = indexValue.asString();
+
+    if (index.empty() || index == "current")
+        return getLedger(ledger, LedgerShortcut::CURRENT, context);
+
+    if (index == "validated")
+        return getLedger(ledger, LedgerShortcut::VALIDATED, context);
+
+    if (index == "closed")
+        return getLedger(ledger, LedgerShortcut::CLOSED, context);
+
+    std::uint32_t iVal;
+    if (beast::lexicalCastChecked(iVal, index))
+        return getLedger(ledger, iVal, context);
+
+    return {rpcINVALID_PARAMS, "ledgerIndexMalformed"};
 }
 }  // namespace
 

src/test/rpc/DepositAuthorized_test.cpp

@@ -228,11 +228,18 @@ class DepositAuthorized_test : public beast::unit_test::suite
         }
         {
             // Request an invalid ledger.
-            Json::Value args{depositAuthArgs(alice, becky, "17")};
+            Json::Value args{depositAuthArgs(alice, becky, "-1")};
             Json::Value const result{
                 env.rpc("json", "deposit_authorized", args.toStyledString())};
             verifyErr(result, "invalidParams", "ledgerIndexMalformed");
         }
+        {
+            // Request a ledger that doesn't exist yet as a string.
+            Json::Value args{depositAuthArgs(alice, becky, "17")};
+            Json::Value const result{
+                env.rpc("json", "deposit_authorized", args.toStyledString())};
+            verifyErr(result, "lgrNotFound", "ledgerNotFound");
+        }
         {
             // Request a ledger that doesn't exist yet.
             Json::Value args{depositAuthArgs(alice, becky)};

src/test/rpc/LedgerRPC_test.cpp

@@ -72,8 +72,24 @@ class LedgerRPC_test : public beast::unit_test::suite
         BEAST_EXPECT(env.current()->info().seq == 4);
 
         {
-            // in this case, numeric string converted to number
-            auto const jrr = env.rpc("ledger", "1")[jss::result];
+            Json::Value jvParams;
+            // can be either numeric or quoted numeric
+            jvParams[jss::ledger_index] = 1;
+            auto const jrr =
+                env.rpc("json", "ledger", to_string(jvParams))[jss::result];
+            BEAST_EXPECT(jrr[jss::ledger][jss::closed] == true);
+            BEAST_EXPECT(jrr[jss::ledger][jss::ledger_index] == "1");
+            BEAST_EXPECT(jrr[jss::ledger][jss::accepted] == true);
+            BEAST_EXPECT(
+                jrr[jss::ledger][jss::totalCoins] ==
+                env.balance(env.master).value().getText());
+        }
+
+        {
+            Json::Value jvParams;
+            jvParams[jss::ledger_index] = "1";
+            auto const jrr =
+                env.rpc("json", "ledger", to_string(jvParams))[jss::result];
             BEAST_EXPECT(jrr[jss::ledger][jss::closed] == true);
             BEAST_EXPECT(jrr[jss::ledger][jss::ledger_index] == "1");
             BEAST_EXPECT(jrr[jss::ledger][jss::accepted] == true);
@@ -110,8 +126,18 @@ class LedgerRPC_test : public beast::unit_test::suite
         env.close();
 
         {
+            // ask for an arbitrary string - index
+            Json::Value jvParams;
+            jvParams[jss::ledger_index] = "potato";
+            auto const jrr =
+                env.rpc("json", "ledger", to_string(jvParams))[jss::result];
+            checkErrorValue(jrr, "invalidParams", "ledgerIndexMalformed");
+        }
+
+        {
+            // ask for a negative index
             Json::Value jvParams;
-            jvParams[jss::ledger_index] = "0";  // NOT an integer
+            jvParams[jss::ledger_index] = -1;
             auto const jrr =
                 env.rpc("json", "ledger", to_string(jvParams))[jss::result];
             checkErrorValue(jrr, "invalidParams", "ledgerIndexMalformed");
@@ -393,8 +419,10 @@ class LedgerRPC_test : public beast::unit_test::suite
     void
     testLedgerEntryDepositPreauth()
     {
-        testcase("ledger_entry Request DepositPreauth");
+        testcase("ledger_entry Deposit Preauth");
+
         using namespace test::jtx;
+
         Env env{*this};
         Account const alice{"alice"};
         Account const becky{"becky"};