runtime-sdk/modules/evm: Fix incorrect return value trimming in queries

runtime-sdk/modules/evm/src/lib.rs

@@ -485,7 +485,7 @@ impl<Cfg: Config> Module<Cfg> {
         ) -> (evm::ExitReason, Vec<u8>),
         C: TxContext,
     {
-        let is_query = ctx.is_check_only();
+        let is_query = ctx.is_check_only() || ctx.is_simulation();
         let cfg = Cfg::evm_config(estimate_gas);
         let gas_limit: u64 = <C::Runtime as Runtime>::Core::remaining_tx_gas(ctx);
         let gas_price: primitive_types::U256 = ctx.tx_auth_info().fee.gas_price().into();

runtime-sdk/modules/evm/src/test.rs

@@ -28,7 +28,6 @@ use oasis_runtime_sdk::{
 use crate::{
     derive_caller,
     mock::{decode_reverted, decode_reverted_raw, load_contract_bytecode, EvmSigner, QueryOptions},
-    state,
     types::{self, H160},
     Config, Genesis, Module as EVMModule,
 };
@@ -1074,4 +1073,24 @@ fn test_return_value_limits() {
     } else {
         panic!("call should revert");
     }
+
+    // Make sure that in query context, the return value is not trimmed.
+    let mut ctx =
+        mock.create_ctx_for_runtime::<EVMRuntime<EVMConfig>>(context::Mode::CheckTx, true);
+
+    let result = signer
+        .query_evm_opts(
+            &mut ctx,
+            contract_address,
+            "testSuccess",
+            &[],
+            &[],
+            Default::default(),
+        )
+        .expect("query should succeed");
+
+    assert_eq!(result.len(), 1120, "result should not be trimmed");
+    // Actual payload is ABI-encoded so the raw result starts at offset 64.
+    assert_eq!(result[64], 0xFF, "result should be correct");
+    assert_eq!(result[1023], 0x42, "result should be correct");
 }