fix: unsupported protocols for chained swaps are always unsupported

not only when the previous swap if of the same protocol!
Improve docs and naming

--- don't change below this line ---
ENG-4314 Took 15 minutes

src/encoding/evm/constants.rs

@@ -19,6 +19,7 @@ pub static GROUPABLE_PROTOCOLS: LazyLock<HashSet<&'static str>> = LazyLock::new(
 });
 
 /// These protocols support the optimization of transferring straight from the user.
+/// Any protocols that are not defined here expect funds to be in the router at the time of swap.
 pub static IN_TRANSFER_OPTIMIZABLE_PROTOCOLS: LazyLock<HashSet<&'static str>> =
     LazyLock::new(|| {
         let mut set = HashSet::new();
@@ -31,10 +32,12 @@ pub static IN_TRANSFER_OPTIMIZABLE_PROTOCOLS: LazyLock<HashSet<&'static str>> =
         set
     });
 
-// These protocols do not support chained swaps from the same protocol. This is the case for uniswap
+// These protocols do not support chained swaps. The tokens can not be sent directly from the
-// v3 because of the callback logic. The only way for this to work it would be to call the second
+// previous pool into a pool of this protocol. The tokens need to be sent to the router and only
-// swap during the callback of the first swap. This is currently not supported.
+// then transferred into the pool. This is the case for uniswap v3 because of the callback logic.
-pub static PROTOCOLS_NOT_OPTIMIZED_CHAINED_SWAPS: LazyLock<HashSet<&'static str>> =
+// The only way for this to work it would be to call the second swap during the callback of the
+// first swap. This is currently not supported.
+pub static UNSUPPORTED_PROTOCOLS_FOR_CHAINED_SWAPS: LazyLock<HashSet<&'static str>> =
     LazyLock::new(|| {
         let mut set = HashSet::new();
         set.insert("uniswap_v3");

src/encoding/evm/strategy_encoder/strategy_encoders.rs

@@ -8,7 +8,7 @@ use crate::encoding::{
     errors::EncodingError,
     evm::{
         approvals::permit2::Permit2,
-        constants::{IN_TRANSFER_OPTIMIZABLE_PROTOCOLS, PROTOCOLS_NOT_OPTIMIZED_CHAINED_SWAPS},
+        constants::{IN_TRANSFER_OPTIMIZABLE_PROTOCOLS, UNSUPPORTED_PROTOCOLS_FOR_CHAINED_SWAPS},
         group_swaps::group_swaps,
         strategy_encoder::{
             strategy_validators::{SequentialSwapValidator, SplitSwapValidator, SwapValidator},
@@ -311,9 +311,8 @@ impl StrategyEncoder for SequentialSwapStrategyEncoder {
                 if IN_TRANSFER_OPTIMIZABLE_PROTOCOLS.contains(&next.protocol_system.as_str()) {
                     // if the protocol does not allow for chained swaps, we can't optimize the
                     // receiver of this swap nor the transfer in of the next swap
-                    if PROTOCOLS_NOT_OPTIMIZED_CHAINED_SWAPS
+                    if UNSUPPORTED_PROTOCOLS_FOR_CHAINED_SWAPS
-                        .contains(&next.protocol_system.as_str()) &&
+                        .contains(&next.protocol_system.as_str())
-                        PROTOCOLS_NOT_OPTIMIZED_CHAINED_SWAPS.contains(protocol.as_str())
                     {
                         next_in_between_swap_optimization = false;
                         self.router_address.clone()

src/encoding/evm/strategy_encoder/transfer_optimizations.rs

@@ -30,7 +30,6 @@ pub trait TransferOptimization {
         } else if (swap.token_in == wrapped_token) && wrap {
             // Wrapping already happened in the router so we can just use a normal transfer.
             TransferType::TransferToProtocol
-            // first swap
         } else if is_first_swap {
             if in_transfer_optimizable {
                 if permit2 {