feat: Add support for CAP-0015 (FeeBumpTransaction).

.xdr/Stellar-ledger-entries.x

@@ -160,11 +160,15 @@ struct AccountEntry
 enum TrustLineFlags
 {
     // issuer has authorized account to perform transactions with its credit
-    AUTHORIZED_FLAG = 1
+    AUTHORIZED_FLAG = 1,
+    // issuer has authorized account to maintain and reduce liabilities for its
+    // credit
+    AUTHORIZED_TO_MAINTAIN_LIABILITIES_FLAG = 2
 };
 
 // mask for all trustline flags
 const MASK_TRUSTLINE_FLAGS = 1;
+const MASK_TRUSTLINE_FLAGS_V13 = 3;
 
 struct TrustLineEntry
 {
@@ -287,9 +291,11 @@ struct LedgerEntry
 // the respective envelopes
 enum EnvelopeType
 {
+    ENVELOPE_TYPE_TX_V0 = 0,
     ENVELOPE_TYPE_SCP = 1,
     ENVELOPE_TYPE_TX = 2,
     ENVELOPE_TYPE_AUTH = 3,
-    ENVELOPE_TYPE_SCPVALUE = 4
+    ENVELOPE_TYPE_SCPVALUE = 4,
+    ENVELOPE_TYPE_TX_FEE_BUMP = 5
 };
 }

.xdr/Stellar-transaction.x

@@ -232,7 +232,8 @@ struct AllowTrustOp
     }
     asset;
 
-    bool authorize;
+    // 0, or any bitwise combination of TrustLineFlags
+    uint32 authorize;
 };
 
 /* Inflation
@@ -353,6 +354,34 @@ struct TimeBounds
 // maximum number of operations per transaction
 const MAX_OPS_PER_TX = 100;
 
+// TransactionV0 is a transaction with the AccountID discriminant stripped off,
+// leaving a raw ed25519 public key to identify the source account. This is used
+// for backwards compatibility starting from the protocol 12/13 boundary. If an
+// "old-style" TransactionEnvelope containing a Transaction is parsed with this
+// XDR definition, it will be parsed as a "new-style" TransactionEnvelope
+// containing a TransactionV0.
+struct TransactionV0
+{
+    uint256 sourceAccountEd25519;
+    uint32 fee;
+    SequenceNumber seqNum;
+    TimeBounds* timeBounds;
+    Memo memo;
+    Operation operations<MAX_OPS_PER_TX>;
+    union switch (int v) {
+    case 0:
+        void;
+    } ext;
+};
+
+struct TransactionV0Envelope
+{
+    TransactionV0 tx;
+    /* Each decorated signature is a signature over the SHA256 hash of
+     * a TransactionSignaturePayload */
+    DecoratedSignature signatures<20>;
+};
+
 /* a transaction is a container for a set of operations
     - is executed by an account
     - fees are collected from the account
@@ -387,27 +416,61 @@ struct Transaction
     ext;
 };
 
-struct TransactionSignaturePayload
+struct TransactionV1Envelope
 {
-    Hash networkId;
+    Transaction tx;
+    /* Each decorated signature is a signature over the SHA256 hash of
+     * a TransactionSignaturePayload */
+    DecoratedSignature signatures<20>;
+};
+
+struct FeeBumpTransaction
+{
+    AccountID feeSource;
+    int64 fee;
     union switch (EnvelopeType type)
     {
     case ENVELOPE_TYPE_TX:
-        Transaction tx;
-        /* All other values of type are invalid */
-    }
-    taggedTransaction;
+        TransactionV1Envelope v1;
+    } innerTx;
+    union switch (int v) {
+    case 0:
+        void;
+    } ext;
 };
 
-/* A TransactionEnvelope wraps a transaction with signatures. */
-struct TransactionEnvelope
+struct FeeBumpTransactionEnvelope
 {
-    Transaction tx;
+    FeeBumpTransaction tx;
     /* Each decorated signature is a signature over the SHA256 hash of
      * a TransactionSignaturePayload */
     DecoratedSignature signatures<20>;
 };
 
+/* A TransactionEnvelope wraps a transaction with signatures. */
+union TransactionEnvelope switch (EnvelopeType type) {
+case ENVELOPE_TYPE_TX_V0:
+    TransactionV0Envelope v0;
+case ENVELOPE_TYPE_TX:
+    TransactionV1Envelope v1;
+case ENVELOPE_TYPE_TX_FEE_BUMP:
+    FeeBumpTransactionEnvelope feeBump;
+};
+
+struct TransactionSignaturePayload
+{
+    Hash networkId;
+    union switch (EnvelopeType type)
+    {
+    // Backwards Compatibility: Use ENVELOPE_TYPE_TX to sign ENVELOPE_TYPE_TX_V0
+    case ENVELOPE_TYPE_TX:
+        Transaction tx;
+    case ENVELOPE_TYPE_TX_FEE_BUMP:
+        FeeBumpTransaction feeBump;
+    }
+    taggedTransaction;
+};
+
 /* Operation Results section */
 
 /* This result is used when offers are taken during an operation */
@@ -859,6 +922,7 @@ default:
 
 enum TransactionResultCode
 {
+    txFEE_BUMP_INNER_SUCCESS = 1, // fee bump inner transaction succeeded
     txSUCCESS = 0, // all operations succeeded
 
     txFAILED = -1, // one of the operations failed (none were applied)
@@ -873,7 +937,54 @@ enum TransactionResultCode
     txNO_ACCOUNT = -8,           // source account not found
     txINSUFFICIENT_FEE = -9,     // fee is too small
     txBAD_AUTH_EXTRA = -10,      // unused signatures attached to transaction
-    txINTERNAL_ERROR = -11       // an unknown error occured
+    txINTERNAL_ERROR = -11,      // an unknown error occured
+
+    txNOT_SUPPORTED = -12,        // transaction type not supported
+    txFEE_BUMP_INNER_FAILED = -13 // fee bump inner transaction failed
+};
+
+// InnerTransactionResult must be binary compatible with TransactionResult
+// because it is be used to represent the result of a Transaction.
+struct InnerTransactionResult
+{
+    // Always 0. Here for binary compatibility.
+    int64 feeCharged;
+
+    union switch (TransactionResultCode code)
+    {
+    // txFEE_BUMP_INNER_SUCCESS is not included
+    case txSUCCESS:
+    case txFAILED:
+        OperationResult results<>;
+    case txTOO_EARLY:
+    case txTOO_LATE:
+    case txMISSING_OPERATION:
+    case txBAD_SEQ:
+    case txBAD_AUTH:
+    case txINSUFFICIENT_BALANCE:
+    case txNO_ACCOUNT:
+    case txINSUFFICIENT_FEE:
+    case txBAD_AUTH_EXTRA:
+    case txINTERNAL_ERROR:
+    case txNOT_SUPPORTED:
+    // txFEE_BUMP_INNER_FAILED is not included
+        void;
+    }
+    result;
+
+    // reserved for future use
+    union switch (int v)
+    {
+    case 0:
+        void;
+    }
+    ext;
+};
+
+struct InnerTransactionResultPair
+{
+    Hash transactionHash;          // hash of the inner transaction
+    InnerTransactionResult result; // result for the inner transaction
 };
 
 struct TransactionResult
@@ -882,6 +993,9 @@ struct TransactionResult
 
     union switch (TransactionResultCode code)
     {
+    case txFEE_BUMP_INNER_SUCCESS:
+    case txFEE_BUMP_INNER_FAILED:
+        InnerTransactionResultPair innerResultPair;
     case txSUCCESS:
     case txFAILED:
         OperationResult results<>;

Pipfile

@@ -25,7 +25,7 @@ mnemonic = "*"
 toml = "*"
 
 [requires]
-python_version = "3.7"
+python_version = "3.8"
 
 [pipenv]
 allow_prereleases = true