add gas fee payer by adding a new payload type

api/doc/spec.json

@@ -12420,6 +12420,56 @@
           }
         }
       },
+      "FeePayerSignature": {
+        "type": "object",
+        "description": "Fee payer signature for fee payer transactions\n\nThis allows you to have transactions across multiple accounts and with a fee payer",
+        "required": [
+          "sender",
+          "secondary_signer_addresses",
+          "secondary_signers",
+          "fee_payer_address",
+          "fee_payer_signer"
+        ],
+        "properties": {
+          "sender": {
+            "$ref": "#/components/schemas/AccountSignature"
+          },
+          "secondary_signer_addresses": {
+            "type": "array",
+            "description": "The other involved parties' addresses",
+            "items": {
+              "$ref": "#/components/schemas/Address"
+            }
+          },
+          "secondary_signers": {
+            "type": "array",
+            "description": "The associated signatures, in the same order as the secondary addresses",
+            "items": {
+              "$ref": "#/components/schemas/AccountSignature"
+            }
+          },
+          "fee_payer_address": {
+            "allOf": [
+              {
+                "$ref": "#/components/schemas/Address"
+              },
+              {
+                "description": "The address of the paying party"
+              }
+            ]
+          },
+          "fee_payer_signer": {
+            "allOf": [
+              {
+                "$ref": "#/components/schemas/AccountSignature"
+              },
+              {
+                "description": "The signature of the fee payer"
+              }
+            ]
+          }
+        }
+      },
       "GasEstimation": {
         "type": "object",
         "description": "Struct holding the outputs of the estimate gas API",
@@ -13394,14 +13444,18 @@
           },
           {
             "$ref": "#/components/schemas/TransactionSignature_MultiAgentSignature"
+          },
+          {
+            "$ref": "#/components/schemas/TransactionSignature_FeePayerSignature"
           }
         ],
         "discriminator": {
           "propertyName": "type",
           "mapping": {
             "ed25519_signature": "#/components/schemas/TransactionSignature_Ed25519Signature",
             "multi_ed25519_signature": "#/components/schemas/TransactionSignature_MultiEd25519Signature",
-            "multi_agent_signature": "#/components/schemas/TransactionSignature_MultiAgentSignature"
+            "multi_agent_signature": "#/components/schemas/TransactionSignature_MultiAgentSignature",
+            "fee_payer_signature": "#/components/schemas/TransactionSignature_FeePayerSignature"
           }
         }
       },
@@ -13424,6 +13478,25 @@
           }
         ]
       },
+      "TransactionSignature_FeePayerSignature": {
+        "allOf": [
+          {
+            "type": "object",
+            "required": [
+              "type"
+            ],
+            "properties": {
+              "type": {
+                "type": "string",
+                "example": "fee_payer_signature"
+              }
+            }
+          },
+          {
+            "$ref": "#/components/schemas/FeePayerSignature"
+          }
+        ]
+      },
       "TransactionSignature_MultiAgentSignature": {
         "allOf": [
           {

api/doc/spec.yaml

@@ -9316,6 +9316,40 @@ components:
           $ref: '#/components/schemas/U64'
         account_address:
           $ref: '#/components/schemas/Address'
+    FeePayerSignature:
+      type: object
+      description: |-
+        Fee payer signature for fee payer transactions
+
+        This allows you to have transactions across multiple accounts and with a fee payer
+      required:
+      - sender
+      - secondary_signer_addresses
+      - secondary_signers
+      - fee_payer_address
+      - fee_payer_signer
+      properties:
+        sender:
+          $ref: '#/components/schemas/AccountSignature'
+        secondary_signer_addresses:
+          type: array
+          description: The other involved parties' addresses
+          items:
+            $ref: '#/components/schemas/Address'
+        secondary_signers:
+          type: array
+          description: The associated signatures, in the same order as the secondary
+            addresses
+          items:
+            $ref: '#/components/schemas/AccountSignature'
+        fee_payer_address:
+          allOf:
+          - $ref: '#/components/schemas/Address'
+          - description: The address of the paying party
+        fee_payer_signer:
+          allOf:
+          - $ref: '#/components/schemas/AccountSignature'
+          - description: The signature of the fee payer
     GasEstimation:
       type: object
       description: Struct holding the outputs of the estimate gas API
@@ -10088,12 +10122,14 @@ components:
       - $ref: '#/components/schemas/TransactionSignature_Ed25519Signature'
       - $ref: '#/components/schemas/TransactionSignature_MultiEd25519Signature'
       - $ref: '#/components/schemas/TransactionSignature_MultiAgentSignature'
+      - $ref: '#/components/schemas/TransactionSignature_FeePayerSignature'
       discriminator:
         propertyName: type
         mapping:
           ed25519_signature: '#/components/schemas/TransactionSignature_Ed25519Signature'
           multi_ed25519_signature: '#/components/schemas/TransactionSignature_MultiEd25519Signature'
           multi_agent_signature: '#/components/schemas/TransactionSignature_MultiAgentSignature'
+          fee_payer_signature: '#/components/schemas/TransactionSignature_FeePayerSignature'
     TransactionSignature_Ed25519Signature:
       allOf:
       - type: object
@@ -10104,6 +10140,16 @@ components:
             type: string
             example: ed25519_signature
       - $ref: '#/components/schemas/Ed25519Signature'
+    TransactionSignature_FeePayerSignature:
+      allOf:
+      - type: object
+        required:
+        - type
+        properties:
+          type:
+            type: string
+            example: fee_payer_signature
+      - $ref: '#/components/schemas/FeePayerSignature'
     TransactionSignature_MultiAgentSignature:
       allOf:
       - type: object

api/src/tests/transactions_test.rs

@@ -250,7 +250,74 @@ async fn test_multi_agent_signed_transaction() {
         .post("/transactions", resp)
         .await;
 }
+/* works when feature is enabled
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_fee_payer_signed_transaction() {
+    let mut context = new_test_context(current_function_name!());
+    let account = context.gen_account();
+    let secondary = context.gen_account();
+    let factory = context.transaction_factory();
+    let mut root_account = context.root_account().await;
+
+    // Create secondary signer account
+    context
+        .commit_block(&[context.create_user_account_by(&mut root_account, &secondary)])
+        .await;
+
+    // Create a new account with a multi-agent signer
+    let txn = root_account.sign_fee_payer_with_transaction_builder(
+        vec![], &secondary,
+        factory.create_user_account(account.public_key()),
+    );
 
+    let body = bcs::to_bytes(&txn).unwrap();
+    let resp = context
+        .expect_status_code(202)
+        .post_bcs_txn("/transactions", body)
+        .await;
+
+    let (sender, secondary_signers,fee_payer_signer) = match txn.authenticator() {
+        TransactionAuthenticator::FeePayer {
+            sender,
+            secondary_signer_addresses: _,
+            secondary_signers,
+            fee_payer_address: _,
+            fee_payer_signer
+        } => (sender, secondary_signers, fee_payer_signer),
+        _ => panic!(
+            "expecting TransactionAuthenticator::MultiAgent, but got: {:?}",
+            txn.authenticator()
+        ),
+    };
+    assert_json(
+        resp["signature"].clone(),
+        json!({
+            "type": "fee_payer_signature",
+            "sender": {
+                "type": "ed25519_signature",
+                "public_key": format!("0x{}", hex::encode(sender.public_key_bytes())),
+                "signature": format!("0x{}", hex::encode(sender.signature_bytes())),
+            },
+            "secondary_signer_addresses": [
+            ],
+            "secondary_signers": [
+            ],
+            "fee_payer_address": secondary.address().to_hex_literal(),
+            "fee_payer_signer": {
+                "type": "ed25519_signature",
+                "public_key": format!("0x{}",hex::encode(fee_payer_signer.public_key_bytes())),
+                "signature": format!("0x{}", hex::encode(fee_payer_signer.signature_bytes())),
+            },
+        }),
+    );
+
+    // ensure fee payer txns can be submitted into mempool by JSON format
+    context
+        .expect_status_code(202)
+        .post("/transactions", resp)
+        .await;
+}
+*/
 #[ignore]
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_multi_ed25519_signed_transaction() {

api/types/src/lib.rs

@@ -47,14 +47,14 @@ pub use table::{RawTableItemRequest, TableItemRequest};
 pub use transaction::{
     AccountSignature, BlockMetadataTransaction, DeleteModule, DeleteResource, DeleteTableItem,
     DirectWriteSet, Ed25519Signature, EncodeSubmissionRequest, EntryFunctionPayload, Event,
-    GasEstimation, GasEstimationBcs, GenesisPayload, GenesisTransaction, ModuleBundlePayload,
-    MultiAgentSignature, MultiEd25519Signature, MultisigPayload, MultisigTransactionPayload,
-    PendingTransaction, ScriptPayload, ScriptWriteSet, SubmitTransactionRequest, Transaction,
-    TransactionData, TransactionId, TransactionInfo, TransactionOnChainData, TransactionPayload,
-    TransactionSignature, TransactionSigningMessage, TransactionsBatchSingleSubmissionFailure,
-    TransactionsBatchSubmissionResult, UserCreateSigningMessageRequest, UserTransaction,
-    UserTransactionRequest, VersionedEvent, WriteModule, WriteResource, WriteSet, WriteSetChange,
-    WriteSetPayload, WriteTableItem,
+    FeePayerSignature, GasEstimation, GasEstimationBcs, GenesisPayload, GenesisTransaction,
+    ModuleBundlePayload, MultiAgentSignature, MultiEd25519Signature, MultisigPayload,
+    MultisigTransactionPayload, PendingTransaction, ScriptPayload, ScriptWriteSet,
+    SubmitTransactionRequest, Transaction, TransactionData, TransactionId, TransactionInfo,
+    TransactionOnChainData, TransactionPayload, TransactionSignature, TransactionSigningMessage,
+    TransactionsBatchSingleSubmissionFailure, TransactionsBatchSubmissionResult,
+    UserCreateSigningMessageRequest, UserTransaction, UserTransactionRequest, VersionedEvent,
+    WriteModule, WriteResource, WriteSet, WriteSetChange, WriteSetPayload, WriteTableItem,
 };
 pub use view::ViewRequest;
 pub use wrappers::{EventGuid, IdentifierWrapper, StateKeyWrapper};