[POLICY] Allow dust anchor outputs

Anchor outputs are not yet required
to be spent in same mempool package.

Author: instagibbs

src/policy/policy.cpp

@@ -141,7 +141,7 @@ bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_dat
         else if ((whichType == TxoutType::MULTISIG) && (!permit_bare_multisig)) {
             reason = "bare-multisig";
             return false;
-        } else if (IsDust(txout, dust_relay_fee)) {
+        } else if (whichType != TxoutType::ANCHOR && IsDust(txout, dust_relay_fee)) {
             reason = "dust";
             return false;
         }

src/test/transaction_tests.cpp

@@ -925,6 +925,13 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
         t.vout[0].nValue = 239;
         CheckIsNotStandard(t, "dust");
     }
+
+    // Check anchor outputs allow dust
+    t.vout[0].scriptPubKey = CScript() << OP_1;
+    t.vout[0].nValue = 0;
+    CheckIsStandard(t);
+    t.vout[0].nValue = 1; // Not just 0
+    CheckIsStandard(t);
 }
 
 BOOST_AUTO_TEST_SUITE_END()