chore(evmrpc): expose eth_blobBaseFee on eth RPC surface

evmrpc/AGENTS.md

@@ -7,6 +7,7 @@ EVM RPCs prefixed by `eth_` and `debug_` on Sei generally follows [Ethereum's sp
 - **No Uncle** - Sei does not have the concept of uncle blocks, so any endpoint relevant to uncle is not supported.
 - **No Trie** - Sei does not store states in a trie, so any endpoint relevant to the trie data structure is not supported.
 - **No PoW** - Sei has never used proof-of-work, so endpoints like `eth_mining` and `eth_hashrate` are not supported.
+- **No Blobs** - Sei does not support EIP-4844 blob transactions. `eth_blobBaseFee` is exposed but returns a JSON-RPC error (code -32000, "blobs not supported on this chain") instead of a fee value.
 
 ## `sei_` prefixed endpoints
 Several `eth_` prefixed endpoints have a `sei_` prefixed counterpart. `eth_` endpoints only have visibility into EVM transactions, whereas `sei_` endpoints have visibility into EVM transactions plus Cosmos transactions that have synthetic EVM receipts.

evmrpc/info.go

@@ -264,6 +264,26 @@ func (i *InfoAPI) MaxPriorityFeePerGas(ctx context.Context) (fee *hexutil.Big, r
 	return (*hexutil.Big)(feeHist.Reward[0][0].ToInt()), nil
 }
 
+// ErrCodeBlobsNotSupported is the JSON-RPC error code (-32000) for blob-not-supported errors.
+// Matches go-ethereum rpc errcodeDefault (unexported).
+const ErrCodeBlobsNotSupported = -32000
+
+type ErrBlobsNotSupported struct{}
+
+func (e *ErrBlobsNotSupported) Error() string {
+	return "blobs not supported on this chain"
+}
+
+func (e *ErrBlobsNotSupported) ErrorCode() int {
+	return ErrCodeBlobsNotSupported
+}
+
+func (i *InfoAPI) BlobBaseFee(ctx context.Context) (result *hexutil.Big, returnErr error) {
+	startTime := time.Now()
+	defer recordMetricsWithError("eth_BlobBaseFee", i.connectionType, startTime, returnErr)
+	return nil, &ErrBlobsNotSupported{}
+}
+
 func (i *InfoAPI) safeGetBaseFee(targetHeight int64) (res *big.Int) {
 	defer func() {
 		if err := recover(); err != nil {

evmrpc/info_test.go

@@ -180,6 +180,32 @@ func TestMaxPriorityFeePerGas(t *testing.T) {
 	assert.Equal(t, "0x3b9aca00", resObj["result"])
 }
 
+func TestBlobBaseFee(t *testing.T) {
+	Ctx = Ctx.WithBlockHeight(1)
+	resObj := sendRequestGood(t, "blobBaseFee")
+	require.Contains(t, resObj, "error", "blobBaseFee should return error (blobs not supported)")
+	errObj := resObj["error"].(map[string]interface{})
+	require.Equal(t, float64(evmrpc.ErrCodeBlobsNotSupported), errObj["code"], "error code should be ErrCodeServerError")
+	require.Equal(t, "blobs not supported on this chain", errObj["message"])
+}
+
+func TestBlobBaseFee_Direct(t *testing.T) {
+	ctxProvider := func(height int64) sdk.Context {
+		if height == evmrpc.LatestCtxHeight {
+			return Ctx.WithBlockHeight(MockHeight8)
+		}
+		return Ctx.WithBlockHeight(height)
+	}
+	api := newInfoAPIWithWatermarks(ctxProvider)
+	fee, err := api.BlobBaseFee(context.Background())
+	require.Error(t, err)
+	require.Nil(t, fee)
+	var errWithCode *evmrpc.ErrBlobsNotSupported
+	require.True(t, errors.As(err, &errWithCode))
+	require.Equal(t, evmrpc.ErrCodeBlobsNotSupported, errWithCode.ErrorCode())
+	require.Contains(t, err.Error(), "blobs not supported")
+}
+
 func TestGasPriceLogic(t *testing.T) {
 	oneGwei := big.NewInt(1000000000)
 	onePointOneGwei := big.NewInt(1100000000)

integration_test/evm_module/rpc_io_test/FAILED_TEST_ANALYSIS.md

@@ -20,7 +20,7 @@
 | debug_getRawHeader | 2 | get-block-n.iox, get-genesis.iox |
 | debug_getRawReceipts | 2 | get-block-n.iox, get-genesis.iox |
 | debug_getRawTransaction | 1 | get-tx.iox |
-| eth_blobBaseFee | 1 | get-current-blobfee.iox |
+| eth_blobBaseFee | 1 | blobs-not-supported-error.iox |
 | eth_call | 1 | call-callenv-options-eip1559.iox (EIP1559 params; Sei returns error) |
 | eth_createAccessList | 3 | create-al-abi-revert, create-al-contract-eip1559, create-al-contract (insufficient funds / gas fee) |
 | eth_estimateGas | 2 | estimate-with-eip4844.iox, estimate-with-eip7702.iox (parse error) |
@@ -44,7 +44,7 @@
 | debug_getRawHeader | get-block-n, get-genesis | No GetRawHeader |
 | debug_getRawReceipts | get-block-n, get-genesis | No GetRawReceipts |
 | debug_getRawTransaction | get-tx.iox | No GetRawTransaction |
-| eth_blobBaseFee | get-current-blobfee.iox | Not exposed on eth API |
+| eth_blobBaseFee | blobs-not-supported-error.iox | Not exposed on eth API |
 | eth_newPendingTransactionFilter | newPendingTransactionFilter.iox | No NewPendingTransactionFilter in FilterAPI |
 | eth_syncing | check-syncing.iox | No Syncing on InfoAPI |
 

integration_test/evm_module/rpc_io_test/RPC_IO_README.md

@@ -261,7 +261,7 @@ So "seed" = a known-good block (and deploy tx) that the script creates and the r
 | debug_getRawReceipts               | get-block-n.iox                                                                   | FAIL   | Sei          | Not implemented        | error code=-32601 message="the method debug_getRawReceipts does not exist/is not available" |
 | debug_getRawReceipts               | get-genesis.iox                                                                   | FAIL   | Sei          | Not implemented        | error code=-32601 message="the method debug_getRawReceipts does not exist/is not available" |
 | debug_getRawTransaction            | get-tx.iox                                                                        | FAIL   | Sei          | Not implemented        | error code=-32601 message="the method debug_getRawTransaction does not exist/is not available" |
-| eth_blobBaseFee                    | get-current-blobfee.iox                                                           | FAIL   | Sei          | Not implemented        | error code=-32601 message="the method eth_blobBaseFee does not exist/is not available" |
+| eth_blobBaseFee                    | blobs-not-supported-error.iox                                                     | FAIL   | Sei          | Not implemented        | error code=-32601 message="the method eth_blobBaseFee does not exist/is not available" |
 | eth_call                           | call-callenv-options-eip1559.iox                                                  | FAIL   | Sei          | Gas fee issue          | error code=-32000 message="max fee per gas less than block base fee" |
 | eth_createAccessList               | create-al-abi-revert.iox                                                          | FAIL   | Sei          | Insufficient funds     | error code=-32000 message="insufficient funds for gas * price + value" |
 | eth_createAccessList               | create-al-contract-eip1559.iox                                                    | FAIL   | Sei          | Gas fee issue          | error code=-32000 message="max fee per gas less than block base fee" |

integration_test/evm_module/rpc_io_test/testdata/eth_blobBaseFee/blobs-not-supported-error.iox

@@ -0,0 +1,3 @@
+// Sei does not support blobs; eth_blobBaseFee returns -32000 with clear message.
+>> {"jsonrpc":"2.0","id":1,"method":"eth_blobBaseFee"}
+<< {"jsonrpc":"2.0","id":1,"error":{"code":-32000,"message":"blobs not supported on this chain"}}