add tecMPT_ISSUANCE_NOT_FOUND code (XRPLF#33)

* add issuance not found code

* add issuance check to start of func

* uses `exists()`

Author: shawnxie999

include/xrpl/protocol/TER.h

@@ -345,6 +345,7 @@ enum TECcodes : TERUnderlyingType {
     tecMPT_MAX_AMOUNT_EXCEEDED = 193,
     tecMPT_LOCKED = 194,
     tecMPT_NOT_SUPPORTED = 195,
+    tecMPT_ISSUANCE_NOT_FOUND = 196
 };
 
 //------------------------------------------------------------------------------

src/libxrpl/protocol/TER.cpp

@@ -119,6 +119,7 @@ transResults()
 		MAKE_ERROR(tecMPTOKEN_EXISTS,                "The account already owns the MPToken object."),
         MAKE_ERROR(tecMPT_MAX_AMOUNT_EXCEEDED,       "The MPT's maximum amount is exceeded."),
         MAKE_ERROR(tecMPT_LOCKED,                    "MPT is locked by the issuer."),
+        MAKE_ERROR(tecMPT_ISSUANCE_NOT_FOUND,        "The MPTokenIssuance object is not found"),
 
         MAKE_ERROR(tefALREADY,                     "The exact transaction was already in this ledger."),
         MAKE_ERROR(tefBAD_ADD_AUTH,                "Not authorized to add account."),

src/test/app/MPToken_test.cpp

@@ -980,6 +980,41 @@ class MPToken_test : public beast::unit_test::suite
                 jrr[jss::result][jss::error_message] ==
                 "Field 'build_path' not allowed in this context.");
         }
+
+        // Issuer fails trying to send fund after issuance was destroyed
+        {
+            Env env{*this, features};
+
+            MPTTester mptAlice(env, alice, {.holders = {&bob}});
+
+            mptAlice.create({.ownerCount = 1, .holderCount = 0});
+
+            mptAlice.authorize({.account = &bob});
+
+            // alice destroys issuance
+            mptAlice.destroy({.ownerCount = 0});
+
+            // alice tries to send bob fund after issuance is destroy, should
+            // fail.
+            mptAlice.pay(alice, bob, 100, tecMPT_ISSUANCE_NOT_FOUND);
+        }
+
+        // Issuer fails trying to send to some who doesn't own MPT for a
+        // issuance that was destroyed
+        {
+            Env env{*this, features};
+
+            MPTTester mptAlice(env, alice, {.holders = {&bob}});
+
+            mptAlice.create({.ownerCount = 1, .holderCount = 0});
+
+            // alice destroys issuance
+            mptAlice.destroy({.ownerCount = 0});
+
+            // alice tries to send bob who doesn't own the MPT after issuance is
+            // destroyed, it should fail
+            mptAlice.pay(alice, bob, 100, tecMPT_ISSUANCE_NOT_FOUND);
+        }
     }
 
     void

src/xrpld/ledger/detail/View.cpp

@@ -1860,6 +1860,10 @@ rippleCredit(
 {
     auto const mptID = keylet::mptIssuance(saAmount.issue().getMptID());
     auto const issuer = saAmount.getIssuer();
+
+    if (!view.exists(mptID))
+        return tecMPT_ISSUANCE_NOT_FOUND;
+
     if (uSenderID == issuer)
     {
         if (auto sle = view.peek(mptID))