Improve try_with_gas readability

Author: webmaster128

packages/vm/src/backend.rs

@@ -195,18 +195,24 @@ pub trait Querier {
 /// must always have gas information attached.
 pub type BackendResult<T> = (core::result::Result<T, BackendError>, GasInfo);
 
-/// The equivalent of the `?` operator, but for a [`BackendResult`]
-macro_rules! try_br {
-    ($res: expr $(,)?) => {
-        let (result, gas) = $res;
-
+/// This aims to be similar to the `?` operator, but for a [`BackendResult`].
+///
+/// The first argument is a result. If it is Ok, return the value.
+/// If it is Err, end the current function with a `return BackendResult::Err`.
+///
+/// The second argument is the gas value that will be used in the error case.
+/// It should be the sum of all gas used in the calling function.
+macro_rules! try_with_gas {
+    ($result: expr $(,)?, $gas_total: expr $(,)?) => {
+        let result: core::result::Result<_, _> = $result; // just a type check
+        let gas: GasInfo = $gas_total; // just a type check
         match result {
             Ok(v) => v,
             Err(e) => return (Err(e), gas),
         }
     };
 }
-pub(crate) use try_br;
+pub(crate) use try_with_gas;
 
 #[derive(Error, Debug, PartialEq, Eq)]
 #[non_exhaustive]

packages/vm/src/testing/mock.rs

@@ -6,7 +6,7 @@ use sha2::{Digest, Sha256};
 
 use super::querier::MockQuerier;
 use super::storage::MockStorage;
-use crate::backend::try_br;
+use crate::backend::try_with_gas;
 use crate::{Backend, BackendApi, BackendError, BackendResult, GasInfo};
 
 pub const MOCK_CONTRACT_ADDR: &str = "cosmwasmcontract"; // TODO: use correct address
@@ -178,7 +178,7 @@ impl BackendApi for MockApi {
             ),
             Ok((_, decoded, Variant::Bech32)) => match Vec::<u8>::from_base32(&decoded) {
                 Ok(bytes) => {
-                    try_br!((validate_length(&bytes), gas_info));
+                    try_with_gas!(validate_length(&bytes), gas_info);
                     (Ok(bytes), gas_info)
                 }
                 Err(_) => (Err(BackendError::user_err("Invalid bech32 data")), gas_info),
@@ -195,7 +195,7 @@ impl BackendApi for MockApi {
             MockApiImpl::Bech32 { bech32_prefix } => bech32_prefix,
         };
 
-        try_br!((validate_length(canonical), gas_info));
+        try_with_gas!(validate_length(canonical), gas_info);
 
         let result = encode(bech32_prefix, canonical.to_base32(), Variant::Bech32)
             .map_err(|_| BackendError::user_err("Invalid bech32 prefix"));