Make NativeToEthRatio part of Environment (#2604)

cmichi · web-flow · commit 2821151a415d · 2025-08-30T00:11:56.000+02:00
* Make `NativeToEthRatio` part of `Environment`

* Update changelog

* Move `balance_to_evm_value` to sandbox top-level

* Add `NATIVE_TO_ETH_RATIO` to missing doc comments

* Fix syntax

* Add `NATIVE_TO_ETH_RATIO` to missing doc comments

* Add `NATIVE_TO_ETH_RATIO` to missing doc comments

* Fix syntax

* Add missing property

* Update schema
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 - E2E: Fixes around correct handling of storage deposit limit ‒ [#2589](https://github.com/use-ink/ink/pull/2589)
+- Make `NativeToEthRatio` part of the `Environment` ‒ [#2604](https://github.com/use-ink/ink/pull/2604)
 
 ## Version 6.0.0-alpha.1
 
diff --git a/crates/e2e/sandbox/src/api/revive_api.rs b/crates/e2e/sandbox/src/api/revive_api.rs
@@ -179,7 +179,7 @@ where
         self.execute_with(|| {
             pallet_revive::Pallet::<Self::T>::bare_instantiate(
                 origin,
-                balance_to_evm_value::<BalanceOf<Self::T>>(value),
+                balance_to_evm_value::<Self::T>(value),
                 gas_limit,
                 storage_deposit_limit,
                 Code::Upload(contract_bytes),
@@ -204,7 +204,7 @@ where
         self.execute_with(|| {
             pallet_revive::Pallet::<Self::T>::bare_instantiate(
                 origin,
-                balance_to_evm_value::<BalanceOf<Self::T>>(value),
+                balance_to_evm_value::<Self::T>(value),
                 gas_limit,
                 storage_deposit_limit,
                 Code::Existing(code_hash),
@@ -244,7 +244,7 @@ where
             pallet_revive::Pallet::<Self::T>::bare_call(
                 origin,
                 address,
-                balance_to_evm_value::<BalanceOf<Self::T>>(value),
+                balance_to_evm_value::<Self::T>(value),
                 gas_limit,
                 storage_deposit_limit,
                 data,
diff --git a/crates/e2e/sandbox/src/lib.rs b/crates/e2e/sandbox/src/lib.rs
@@ -26,6 +26,7 @@ use pallet_revive::{
     ExecReturnValue,
     InstantiateReturnValue,
 };
+use sp_core::Get;
 /// Export pallets that are used in [`crate::create_sandbox`]
 pub use {
     frame_support::sp_runtime::testing::H256,
@@ -158,11 +159,14 @@ pub trait Sandbox {
 /// the other way (from `U256` to `Balance`).
 ///
 /// See <https://github.com/paritytech/polkadot-sdk/pull/9101> for more details.
-pub fn balance_to_evm_value<Balance>(value: Balance) -> U256
+pub fn balance_to_evm_value<R>(value: BalanceOf<R>) -> U256
 where
-    Balance: Into<U256>,
+    R: pallet_revive::Config,
+    BalanceOf<R>: Into<U256>,
+    U256: From<u32>,
 {
-    let native_to_eth_ratio: U256 = 100_000_000.into();
+    let native_to_eth_ratio: U256 =
+        <R as pallet_revive::Config>::NativeToEthRatio::get().into();
     let evm_value: U256 = value.into();
-    native_to_eth_ratio.saturating_mul(evm_value)
+    native_to_eth_ratio.saturating_mul(evm_value.into())
 }
diff --git a/crates/ink/codegen/src/generator/env.rs b/crates/ink/codegen/src/generator/env.rs
@@ -41,6 +41,7 @@ impl GenerateCode for Env<'_> {
             type BlockNumber = <<#storage_ident as ::ink::env::ContractEnv>::Env as ::ink::env::Environment>::BlockNumber;
             type ChainExtension = <<#storage_ident as ::ink::env::ContractEnv>::Env as ::ink::env::Environment>::ChainExtension;
             const MAX_EVENT_TOPICS: usize = <<#storage_ident as ::ink::env::ContractEnv>::Env as ::ink::env::Environment>::MAX_EVENT_TOPICS;
+            const NATIVE_TO_ETH_RATIO: u32 = <<#storage_ident as ::ink::env::ContractEnv>::Env as ::ink::env::Environment>::NATIVE_TO_ETH_RATIO;
             type EventRecord = <<#storage_ident as ::ink::env::ContractEnv>::Env as ::ink::env::Environment>::EventRecord;
 
             type Address = ::ink::primitives::Address;
diff --git a/crates/ink/macro/src/lib.rs b/crates/ink/macro/src/lib.rs
@@ -167,6 +167,7 @@ pub fn selector_bytes(input: TokenStream) -> TokenStream {
 ///
 ///   impl ink_env::Environment for MyEnvironment {
 ///       const MAX_EVENT_TOPICS: usize = 3;
+///       const NATIVE_TO_ETH_RATIO: u32 = 100_000_000;
 ///       type AccountId = [u8; 16];
 ///       type Balance = u128;
 ///       type Hash = [u8; 32];
@@ -186,6 +187,7 @@ pub fn selector_bytes(input: TokenStream) -> TokenStream {
 ///       #
 ///       # impl ink_env::Environment for MyEnvironment {
 ///       #     const MAX_EVENT_TOPICS: usize = 3;
+///       #     const NATIVE_TO_ETH_RATIO: u32 = 100_000_000;
 ///       #     type AccountId = [u8; 16];
 ///       #     type Balance = u128;
 ///       #     type Hash = [u8; 32];
@@ -1180,6 +1182,8 @@ pub fn test(attr: TokenStream, item: TokenStream) -> TokenStream {
 /// impl Environment for CustomEnvironment {
 ///     const MAX_EVENT_TOPICS: usize =
 ///         <DefaultEnvironment as Environment>::MAX_EVENT_TOPICS;
+///     const NATIVE_TO_ETH_RATIO: u32 =
+///         <DefaultEnvironment as Environment>::NATIVE_TO_ETH_RATIO;
 ///
 ///     type AccountId = <DefaultEnvironment as Environment>::AccountId;
 ///     type Balance = <DefaultEnvironment as Environment>::Balance;
@@ -1322,6 +1326,8 @@ pub fn test(attr: TokenStream, item: TokenStream) -> TokenStream {
 /// # impl ink_env::Environment for CustomEnvironment {
 /// #     const MAX_EVENT_TOPICS: usize =
 /// #         <ink_env::DefaultEnvironment as ink_env::Environment>::MAX_EVENT_TOPICS;
+/// #     const NATIVE_TO_ETH_RATIO: u32 =
+/// #         <ink_env::DefaultEnvironment as ink_env::Environment>::NATIVE_TO_ETH_RATIO;
 /// #
 /// #     type AccountId = <ink_env::DefaultEnvironment as ink_env::Environment>::AccountId;
 /// #     type Balance = <ink_env::DefaultEnvironment as ink_env::Environment>::Balance;
diff --git a/crates/ink/src/contract_ref.rs b/crates/ink/src/contract_ref.rs
@@ -153,6 +153,7 @@ use ink_primitives::Address;
 ///
 /// impl ink_env::Environment for CustomEnv {
 ///     const MAX_EVENT_TOPICS: usize = 3;
+///     const NATIVE_TO_ETH_RATIO: u32 = 100_000_000;
 ///     type AccountId = [u8; 32];
 ///     type Balance = u64;
 ///     type Hash = [u8; 32];
diff --git a/crates/ink/src/message_builder.rs b/crates/ink/src/message_builder.rs
@@ -78,6 +78,7 @@
 ///
 /// impl ink_env::Environment for CustomEnv {
 ///     const MAX_EVENT_TOPICS: usize = 3;
+///     const NATIVE_TO_ETH_RATIO: u32 = 100_000_000;
 ///     type AccountId = [u8; 32];
 ///     type Balance = u64;
 ///     type Hash = [u8; 32];
diff --git a/crates/ink/tests/ui/chain_extension/E-01-simple.rs b/crates/ink/tests/ui/chain_extension/E-01-simple.rs
@@ -111,6 +111,8 @@ pub enum CustomEnvironment {}
 impl Environment for CustomEnvironment {
     const MAX_EVENT_TOPICS: usize =
         <ink_env::DefaultEnvironment as Environment>::MAX_EVENT_TOPICS;
+    const NATIVE_TO_ETH_RATIO: u32 =
+        <ink_env::DefaultEnvironment as Environment>::NATIVE_TO_ETH_RATIO;
 
     type AccountId = <ink_env::DefaultEnvironment as Environment>::AccountId;
     type Balance = <ink_env::DefaultEnvironment as Environment>::Balance;
diff --git a/crates/ink/tests/ui/contract/pass/config-custom-env.rs b/crates/ink/tests/ui/contract/pass/config-custom-env.rs
@@ -5,6 +5,7 @@ pub struct CustomEnv;
 
 impl ink_env::Environment for CustomEnv {
     const MAX_EVENT_TOPICS: usize = 3;
+    const NATIVE_TO_ETH_RATIO: u32 = 100_000_000;
     type AccountId = [u8; 32];
     type Balance = u64;
     type Hash = [u8; 32];
diff --git a/crates/ink/tests/ui/contract/pass/event/event-config-more-topics.rs b/crates/ink/tests/ui/contract/pass/event/event-config-more-topics.rs
@@ -10,6 +10,7 @@ pub struct EnvironmentMoreTopics;
 
 impl ink_env::Environment for EnvironmentMoreTopics {
     const MAX_EVENT_TOPICS: usize = 10; // Default is 4.
+    const NATIVE_TO_ETH_RATIO: u32 = 100_000_000;
 
     type AccountId = <DefaultEnvironment as Environment>::AccountId;
     type Balance = <DefaultEnvironment as Environment>::Balance;
diff --git a/crates/metadata/contract_schema.json b/crates/metadata/contract_schema.json
@@ -241,6 +241,7 @@
         "chainExtension",
         "hash",
         "maxEventTopics",
+        "nativeToEthRatio",
         "timestamp"
       ],
       "properties": {
@@ -264,6 +265,11 @@
           "format": "uint",
           "minimum": 0.0
         },
+        "nativeToEthRatio": {
+           "type": "integer",
+           "format": "uint",
+           "minimum": 0.0
+        },
         "timestamp": {
           "$ref": "#/definitions/TypeSpec_for_PortableForm"
         }
@@ -1183,4 +1189,4 @@
       }
     }
   }
-}
+}
diff --git a/crates/metadata/src/specs.rs b/crates/metadata/src/specs.rs
@@ -1552,6 +1552,7 @@ where
     block_number: TypeSpec<F>,
     chain_extension: TypeSpec<F>,
     max_event_topics: usize,
+    native_to_eth_ratio: u32,
     static_buffer_size: usize,
 }
 
@@ -1569,6 +1570,7 @@ where
             block_number: Default::default(),
             chain_extension: Default::default(),
             max_event_topics: Default::default(),
+            native_to_eth_ratio: Default::default(),
             static_buffer_size: Default::default(),
         }
     }
@@ -1586,6 +1588,7 @@ impl IntoPortable for EnvironmentSpec {
             block_number: self.block_number.into_portable(registry),
             chain_extension: self.chain_extension.into_portable(registry),
             max_event_topics: self.max_event_topics,
+            native_to_eth_ratio: self.native_to_eth_ratio,
             static_buffer_size: self.static_buffer_size,
         }
     }
@@ -1624,6 +1627,10 @@ where
     pub fn max_event_topics(&self) -> usize {
         self.max_event_topics
     }
+    /// Returns the `NATIVE_TO_ETH_RATIO` value of the environment.
+    pub fn native_to_eth_ratio(&self) -> u32 {
+        self.native_to_eth_ratio
+    }
 }
 
 #[allow(clippy::type_complexity)]
diff --git a/crates/metadata/src/tests.rs b/crates/metadata/src/tests.rs
@@ -593,6 +593,7 @@ fn spec_contract_json() {
                     "type": 10,
                 },
                 "maxEventTopics": 4,
+                "nativeToEthRatio": 100000000,
                 "timestamp":  {
                     "displayName":  [
                         "Timestamp",
diff --git a/crates/primitives/src/contract.rs b/crates/primitives/src/contract.rs
@@ -67,6 +67,8 @@ use crate::types::Environment;
 ///
 /// impl Environment for CustomEnvironment {
 ///     const MAX_EVENT_TOPICS: usize = 4;
+///     const NATIVE_TO_ETH_RATIO: u32 =
+///         <DefaultEnvironment as Environment>::NATIVE_TO_ETH_RATIO;
 ///
 ///     type AccountId = <DefaultEnvironment as Environment>::AccountId;
 ///     type Balance = u64;
diff --git a/crates/primitives/src/types.rs b/crates/primitives/src/types.rs
@@ -34,7 +34,10 @@ use {
     scale_info::TypeInfo,
 };
 
-use crate::arithmetic::AtLeast32BitUnsigned;
+use crate::arithmetic::{
+    AtLeast32BitUnsigned,
+    Saturating,
+};
 
 /// The default environment `AccountId` type.
 ///
@@ -325,6 +328,10 @@ pub trait Environment: Clone {
     /// runtime.
     const MAX_EVENT_TOPICS: usize;
 
+    /// The ratio between the decimal representation of the native `Balance` token
+    /// and the ETH token.
+    const NATIVE_TO_ETH_RATIO: u32;
+
     /// The account id type.
     type AccountId: 'static
         + scale::Codec
@@ -346,6 +353,7 @@ pub trait Environment: Clone {
         + PartialEq
         + Eq
         + AtLeast32BitUnsigned
+        + Into<U256>
         + FromLittleEndian;
 
     /// The type of hash.
@@ -395,6 +403,21 @@ pub trait Environment: Clone {
 
     /// TODO comment
     type EventRecord: 'static + scale::Codec;
+
+    /// Converts from the generic `Balance` type to the Ethereum native `U256`.
+    ///
+    /// # Developer Note
+    ///
+    /// `pallet-revive` uses both types, hence we have to convert in between them
+    /// for certain functions. Notice that precision loss might occur when converting
+    /// the other way (from `U256` to `Balance`).
+    ///
+    /// See <https://github.com/paritytech/polkadot-sdk/pull/9101> for more details.
+    fn native_to_eth(value: Self::Balance) -> U256 {
+        value
+            .saturating_mul(Self::NATIVE_TO_ETH_RATIO.into())
+            .into()
+    }
 }
 
 /// Placeholder for chains that have no defined chain extension.
@@ -409,6 +432,11 @@ pub enum DefaultEnvironment {}
 impl Environment for DefaultEnvironment {
     const MAX_EVENT_TOPICS: usize = 4;
 
+    // This number was chosen as it's also what `pallet-revive`
+    // chooses by default. It's also the number present in the
+    // `ink_sandbox` and the `ink-node`.
+    const NATIVE_TO_ETH_RATIO: u32 = 100_000_000;
+
     type AccountId = AccountId;
     type Balance = Balance;
     type Hash = Hash;
diff --git a/integration-tests/internal/e2e-runtime-only-backend/lib.rs b/integration-tests/internal/e2e-runtime-only-backend/lib.rs
@@ -49,6 +49,7 @@ pub mod flipper {
     #[cfg(all(test, feature = "e2e-tests"))]
     mod e2e_tests {
         use super::*;
+        use ink::env::Environment;
         use ink_e2e::{
             subxt::dynamic::Value,
             ChainBackend,
@@ -160,10 +161,8 @@ pub mod flipper {
                 .expect("get_contract_balance failed")
                 .return_value();
 
-            // todo make `NativeToEthRatio` part of  the `Environment`
-            #[allow(non_upper_case_globals)]
-            const NativeToEthRatio: u128 = 100_000_000;
-            assert_eq!(old_balance + (ENDOWMENT * NativeToEthRatio), new_balance);
+            let endowment_u256 = ink::env::DefaultEnvironment::native_to_eth(ENDOWMENT);
+            assert_eq!(old_balance + endowment_u256, new_balance);
             Ok(())
         }
 
diff --git a/integration-tests/public/combined-extension/lib.rs b/integration-tests/public/combined-extension/lib.rs
@@ -39,6 +39,8 @@ pub enum CustomEnvironment {}
 /// [`Environment::ChainExtension`] type.
 impl Environment for CustomEnvironment {
     const MAX_EVENT_TOPICS: usize = <DefaultEnvironment as Environment>::MAX_EVENT_TOPICS;
+    const NATIVE_TO_ETH_RATIO: u32 =
+        <DefaultEnvironment as Environment>::NATIVE_TO_ETH_RATIO;
 
     type AccountId = <DefaultEnvironment as Environment>::AccountId;
     type Balance = <DefaultEnvironment as Environment>::Balance;
diff --git a/integration-tests/public/contract-transfer/lib.rs b/integration-tests/public/contract-transfer/lib.rs
@@ -191,6 +191,7 @@ pub mod give_me {
     #[cfg(all(test, feature = "e2e-tests"))]
     mod e2e_tests {
         use super::*;
+        use ink::env::Environment;
         use ink_e2e::{
             ChainBackend,
             ContractsBackend,
@@ -235,7 +236,6 @@ pub mod give_me {
             Ok(())
         }
 
-        //#[ink_e2e::test]
         #[ink_e2e::test(backend(runtime_only))]
         async fn e2e_contract_must_transfer_value_to_sender<Client: E2EBackend>(
             mut client: Client,
@@ -251,12 +251,9 @@ pub mod give_me {
                 .expect("instantiate failed");
             let contract_addr = contract.addr;
 
-            // todo make `NativeToEthRatio` part of  the `Environment`
-            #[allow(non_upper_case_globals)]
-            const NativeToEthRatio: u128 = 100_000_000;
             assert_eq!(
                 contract.trace.clone().unwrap().value,
-                Some(U256::from(1_337_000_000 * NativeToEthRatio))
+                Some(ink::env::DefaultEnvironment::native_to_eth(1_337_000_000))
             );
             let mut call_builder = contract.call_builder::<GiveMe>();
 
diff --git a/integration-tests/public/custom-environment/lib.rs b/integration-tests/public/custom-environment/lib.rs
@@ -18,6 +18,9 @@ impl Environment for EnvironmentWithManyTopics {
     const MAX_EVENT_TOPICS: usize =
         <DefaultEnvironment as Environment>::MAX_EVENT_TOPICS - 1;
 
+    const NATIVE_TO_ETH_RATIO: u32 =
+        <DefaultEnvironment as Environment>::NATIVE_TO_ETH_RATIO;
+
     type AccountId = <DefaultEnvironment as Environment>::AccountId;
     type Balance = <DefaultEnvironment as Environment>::Balance;
     type Hash = <DefaultEnvironment as Environment>::Hash;
diff --git a/integration-tests/public/debugging-strategies/lib.rs b/integration-tests/public/debugging-strategies/lib.rs
@@ -109,6 +109,7 @@ mod debugging_strategies {
     #[cfg(all(test, feature = "e2e-tests"))]
     mod e2e_tests {
         use super::*;
+        use ink::env::Environment;
         use ink_e2e::ContractsBackend;
 
         type E2EResult<T> = std::result::Result<T, Box<dyn std::error::Error>>;
@@ -300,12 +301,9 @@ mod debugging_strategies {
             // ```
 
             // then
-            // todo make `NativeToEthRatio` part of  the `Environment`
-            #[allow(non_upper_case_globals)]
-            const NativeToEthRatio: u128 = 100_000_000;
             assert_eq!(
                 trace.value,
-                Some(ink::U256::from(1_337_000_000 * NativeToEthRatio))
+                Some(ink::env::DefaultEnvironment::native_to_eth(1_337_000_000))
             );
 
             Ok(())
diff --git a/integration-tests/public/e2e-call-runtime/lib.rs b/integration-tests/public/e2e-call-runtime/lib.rs
diff --git a/integration-tests/public/psp22-extension/lib.rs b/integration-tests/public/psp22-extension/lib.rs
diff --git a/integration-tests/public/rand-extension/lib.rs b/integration-tests/public/rand-extension/lib.rs
diff --git a/integration-tests/public/runtime-call-contract/sandbox-runtime/pallet-revive-caller/src/executor.rs b/integration-tests/public/runtime-call-contract/sandbox-runtime/pallet-revive-caller/src/executor.rs
