Fix require statement detection inside loops and add tests for it

Author: rkalis

packages/cashscript/src/debugging.ts

@@ -75,9 +75,12 @@ const debugSingleScenario = (
   const lockingScriptDebugResult = fullDebugSteps.slice(findLastIndex(fullDebugSteps, (state) => state.ip === 0));
 
   // The controlStack determines whether the current debug step is in the executed branch
+  // It also tracks loop / function usage, but for the purpose of determining whether a step was executed,
+  // we only need to check that there are no 'false' items in the control stack.
   // https://libauth.org/types/AuthenticationProgramStateControlStack.html
+  // https://github.com/bitjson/bch-loops#control-stack
   const executedDebugSteps = lockingScriptDebugResult
-    .filter((debugStep) => debugStep.controlStack.every(item => item === true));
+    .filter((debugStep) => debugStep.controlStack.every(item => item !== false));
 
   // P2PKH inputs do not have an artifact, so we skip the console.log handling
   if (artifact) {

packages/cashscript/test/debugging.test.ts

@@ -13,6 +13,7 @@ import {
   artifactTestSingleFunction,
   artifactTestMultilineRequires,
   artifactTestZeroHandling,
+  artifactTestRequireInsideLoop,
 } from './fixture/debugging/debugging_contracts.js';
 import { sha256 } from '@cashscript/utils';
 
@@ -167,6 +168,10 @@ describe('Debugging tests', () => {
     const contractTestMultiLineRequiresUtxo = randomUtxo();
     provider.addUtxo(contractTestMultiLineRequires.address, contractTestMultiLineRequiresUtxo);
 
+    const contractTestRequireInsideLoop = new Contract(artifactTestRequireInsideLoop, [], { provider });
+    const contractTestRequireInsideLoopUtxo = randomUtxo();
+    provider.addUtxo(contractTestRequireInsideLoop.address, contractTestRequireInsideLoopUtxo);
+
     // test_require
     it('should fail with error message when require statement fails in a multi-function contract', async () => {
       const transaction = new TransactionBuilder({ provider })
@@ -450,6 +455,17 @@ describe('Debugging tests', () => {
       ])
     );`);
     });
+
+    it('should fail a require statement inside a loop', async () => {
+      const transaction = new TransactionBuilder({ provider })
+        .addInput(contractTestRequireInsideLoopUtxo, contractTestRequireInsideLoop.unlock.test_require_inside_loop())
+        .addOutput({ to: contractTestRequireInsideLoop.address, amount: 10000n });
+
+      expect(transaction).toFailRequireWith('Test.cash:7 Require statement failed at input 0 in contract Test.cash at line 7 with the following message: i should be less than 6.');
+      expect(transaction).toFailRequireWith('Failing statement: require(i < 6, \'i should be less than 6\')');
+    });
+
+    it.todo('should fail correct require statement inside nested loops');
   });
 
   describe('Non-require error messages', () => {

packages/cashscript/test/fixture/debugging/debugging_contracts.ts

@@ -94,6 +94,18 @@ contract Test() {
 }
 `;
 
+const CONTRACT_TEST_REQUIRE_INSIDE_LOOP = `
+contract Test() {
+  function test_require_inside_loop() {
+    int i = 0;
+    do {
+      i = i + 1;
+      require(i < 6, 'i should be less than 6');
+    } while (i < 10);
+  }
+}
+`;
+
 const CONTRACT_TEST_REQUIRE_SINGLE_FUNCTION = `
 contract Test() {
   function test_require_single_function() {
@@ -321,3 +333,4 @@ export const artifactTestLogs = compileString(CONTRACT_TEST_LOGS);
 export const artifactTestConsecutiveLogs = compileString(CONTRACT_TEST_CONSECUTIVE_LOGS);
 export const artifactTestMultipleLogs = compileString(CONTRACT_TEST_MULTIPLE_LOGS);
 export const artifactTestMultipleConstructorParameters = compileString(CONTRACT_TEST_MULTIPLE_CONSTRUCTOR_PARAMETERS);
+export const artifactTestRequireInsideLoop = compileString(CONTRACT_TEST_REQUIRE_INSIDE_LOOP);