feat: (wip) get info about transaction type currently building

crates/network/src/any/builder.rs

@@ -1,6 +1,6 @@
 use std::ops::{Deref, DerefMut};
 
-use alloy_consensus::BlobTransactionSidecar;
+use alloy_consensus::{BlobTransactionSidecar, TxType};
 use alloy_rpc_types::{AccessList, TransactionRequest, WithOtherFields};
 
 use crate::{
@@ -122,6 +122,14 @@ impl TransactionBuilder<AnyNetwork> for WithOtherFields<TransactionRequest> {
         self.deref().can_submit()
     }
 
+    fn output_tx_type(&self) -> TxType {
+        self.deref().output_tx_type()
+    }
+
+    fn output_tx_type_checked(&self) -> BuilderResult<TxType> {
+        self.deref().output_tx_type_checked()
+    }
+
     fn build_unsigned(self) -> BuilderResult<<AnyNetwork as Network>::UnsignedTx> {
         build_unsigned::<AnyNetwork>(self.inner)
     }

crates/network/src/ethereum/builder.rs

@@ -141,6 +141,22 @@ impl TransactionBuilder<Ethereum> for TransactionRequest {
         common && (legacy || eip2930 || eip1559 || eip4844)
     }
 
+    fn output_tx_type(&self) -> TxType {
+        todo!()
+    }
+
+    fn output_tx_type_checked(&self) -> BuilderResult<TxType> {
+        if will_build_4844(self)? {
+            Ok(TxType::Eip4844)
+        } else if will_build_2930(self)? {
+            Ok(TxType::Eip2930)
+        } else if will_build_legacy(self)? {
+            Ok(TxType::Legacy)
+        } else {
+            Ok(TxType::Eip1559)
+        }
+    }
+
     fn build_unsigned(self) -> BuilderResult<TypedTransaction> {
         build_unsigned::<Ethereum>(self)
     }
@@ -159,14 +175,11 @@ where
     N: Network,
     N::UnsignedTx: From<TxLegacy> + From<TxEip1559> + From<TxEip2930> + From<TxEip4844Variant>,
 {
-    if will_build_4844(&request)? {
-        build_4844(request).map(TxEip4844Variant::from).map(Into::into)
-    } else if will_build_2930(&request)? {
-        build_2930(request).map(Into::into)
-    } else if will_build_legacy(&request)? {
-        build_legacy(request).map(Into::into)
-    } else {
-        build_1559(request).map(Into::into)
+    match request.output_tx_type_checked()? {
+        TxType::Legacy => build_legacy(request).map(Into::into),
+        TxType::Eip2930 => build_2930(request).map(Into::into),
+        TxType::Eip1559 => build_1559(request).map(Into::into),
+        TxType::Eip4844 => build_4844(request).map(TxEip4844Variant::from).map(Into::into),
     }
 }
 

crates/network/src/transaction/builder.rs

@@ -278,6 +278,14 @@ pub trait TransactionBuilder<N: Network>: Default + Sized + Send + Sync + 'stati
     /// a valid transaction.
     fn can_build(&self) -> bool;
 
+    /// Returns the transaction type that this builder will attempt to build. This does not imply
+    /// that the builder is ready to build.
+    fn output_tx_type(&self) -> TxType;
+
+    /// Returns the transaction type that this builder will build. `Err` if the builder
+    /// is not ready to build, containing the attempt type and missing/conflicted information
+    fn output_tx_type_checked(&self) -> BuilderResult<TxType>;
+
     /// Build an unsigned, but typed, transaction.
     fn build_unsigned(self) -> BuilderResult<N::UnsignedTx>;