fix: loader contract being called via proxy

.changeset/grumpy-flies-sleep.md

@@ -0,0 +1,5 @@
+---
+"@fuel-ts/contract": patch
+---
+
+fix: loader contract being called via proxy

packages/contract/src/loader/loader-script.test.ts

@@ -13,7 +13,7 @@ describe('Loader Script', () => {
     const actual = getLoaderInstructions(blobIds);
 
     const expected = new Uint8Array([
-      26, 64, 192, 0, 80, 65, 0, 48, 26, 88, 80, 0, 114, 76, 0, 3, 186, 69, 0, 0, 50, 64, 4, 65, 80,
+      26, 64, 48, 0, 80, 65, 0, 48, 26, 88, 80, 0, 114, 76, 0, 3, 186, 69, 0, 0, 50, 64, 4, 65, 80,
       65, 0, 32, 89, 77, 48, 1, 119, 76, 0, 3, 32, 89, 99, 0, 82, 89, 96, 4, 74, 88, 0, 0, 1, 2, 3,
     ]);
     expect(actual).toStrictEqual(expected);

packages/contract/src/loader/loader-script.ts

@@ -13,7 +13,7 @@ export const getLoaderInstructions = (blobIds: string[]): Uint8Array => {
   // Bytes for the Blob Ids
   const blobIdBytes = concat(blobIds.map((b) => arrayify(b)));
 
-  // Reference: https://github.com/FuelLabs/fuels-ts/issues/2741#issuecomment-2260364179
+  // Reference: https://github.com/FuelLabs/fuels-rs/blob/master/packages/fuels-programs/src/contract/loader.rs
   // There are 2 main steps:
   // 1. Load the blob contents into memory
   // 2. Jump to the beginning of the memory where the blobs were loaded
@@ -22,7 +22,7 @@ export const getLoaderInstructions = (blobIds: string[]): Uint8Array => {
   const instructionBytes = new InstructionSet(
     // 1. load the blob contents into memory
     // find the start of the hardcoded blob ids, which are located after the code ends
-    asm.move_(0x10, RegId.is().to_u8()),
+    asm.move_(0x10, RegId.pc().to_u8()),
     // 0x10 to hold the address of the current blob id
     asm.addi(0x10, 0x10, numberOfInstructions * Instruction.size()),
     // The contract is going to be loaded from the current value of SP onwards, save

packages/fuel-gauge/src/contract-factory.test.ts

@@ -11,6 +11,7 @@ import {
   ConfigurableContractFactory,
   LargeContract,
   ConfigurableContract,
+  ProxyContractFactory,
 } from '../test/typegen';
 
 import { launchTestContract } from './utils';
@@ -553,4 +554,37 @@ describe('Contract Factory', () => {
     const { value: secondValue } = await secondCall.waitForResult();
     expect(secondValue.toNumber()).toBe(1001);
   }, 25000);
+
+  it('deploys large contract and calls via a proxy', async () => {
+    using launched = await launchTestNode();
+
+    const {
+      wallets: [wallet],
+    } = launched;
+
+    const largeContractDeploy = await LargeContractFactory.deploy(wallet);
+    const { contract: largeContract } = await largeContractDeploy.waitForResult();
+    expect(largeContract.id).toBeDefined();
+
+    const largeContractCall = await largeContract.functions.something().call();
+    const { value: largeContractValue } = await largeContractCall.waitForResult();
+    expect(largeContractValue.toNumber()).toBe(1001);
+
+    const proxyContractDeploy = await ProxyContractFactory.deploy(wallet);
+    const { contract: proxyContract } = await proxyContractDeploy.waitForResult();
+    expect(proxyContract.id).toBeDefined();
+
+    const setTargetCall = await proxyContract.functions
+      .set_target_contract({ bits: largeContract.id.toB256() })
+      .call();
+    const setTargetResult = await setTargetCall.waitForResult();
+    expect(setTargetResult.transactionResult.isStatusSuccess).toBe(true);
+
+    const proxyCall = await proxyContract.functions
+      .something()
+      .addContracts([largeContract])
+      .call();
+    const { value: proxyValue } = await proxyCall.waitForResult();
+    expect(proxyValue.toNumber()).toBe(1001);
+  }, 25000);
 });

packages/fuel-gauge/test/fixtures/forc-projects/Forc.toml

@@ -39,6 +39,7 @@ members = [
   "predicate-validate-transfer",
   "predicate-vector-types",
   "predicate-with-configurable",
+  "proxy-contract",
   "raw-slice-contract",
   "reentrant-bar",
   "reentrant-foo",

packages/fuel-gauge/test/fixtures/forc-projects/proxy-contract/Forc.toml

@@ -0,0 +1,7 @@
+[project]
+authors = ["Fuel Labs <contact@fuel.sh>"]
+entry = "main.sw"
+license = "Apache-2.0"
+name = "proxy-contract"
+
+[dependencies]

packages/fuel-gauge/test/fixtures/forc-projects/proxy-contract/src/main.sw

@@ -0,0 +1,29 @@
+contract;
+
+use std::execution::run_external;
+
+abi Proxy {
+    #[storage(write)]
+    fn set_target_contract(id: ContractId);
+
+    // this targets the method of the `large_contract project
+    #[storage(read)]
+    fn something() -> u64;
+}
+
+storage {
+    target_contract: Option<ContractId> = None,
+}
+
+impl Proxy for Contract {
+    #[storage(write)]
+    fn set_target_contract(id: ContractId) {
+        storage.target_contract.write(Some(id));
+    }
+
+    #[storage(read)]
+    fn something() -> u64 {
+        let target = storage.target_contract.read().unwrap();
+        run_external(target)
+    }
+}