1 files changed, 21 insertions, 13 deletions

diff --git a/packages/sol-cov/src/trace.ts b/packages/sol-cov/src/trace.ts
index 4d106e355..cb5410909 100644
--- a/packages/sol-cov/src/trace.ts
+++ b/packages/sol-cov/src/trace.ts
@@ -8,6 +8,10 @@ export interface TraceByContractAddress {
     [contractAddress: string]: StructLog[];
 }
 
+function getAddressFromStackEntry(stackEntry: string): string {
+    return addressUtils.padZeros(new BigNumber(addHexPrefix(stackEntry)).toString(16));
+}
+
 export function getTracesByContractAddress(structLogs: StructLog[], startAddress: string): TraceByContractAddress {
     const traceByContractAddress: TraceByContractAddress = {};
     let currentTraceSegment = [];
@@ -16,26 +20,32 @@ export function getTracesByContractAddress(structLogs: StructLog[], startAddress
     for (let i = 0; i < structLogs.length; i++) {
         const structLog = structLogs[i];
         if (structLog.depth !== callStack.length - 1) {
-            throw new Error("Malformed trace. trace depth doesn't match call stack depth");
+            throw new Error("Malformed trace. Trace depth doesn't match call stack depth");
         }
         // After that check we have a guarantee that call stack is never empty
         // If it would: callStack.length - 1 === structLog.depth === -1
         // That means that we can always safely pop from it
         currentTraceSegment.push(structLog);
 
-        if (_.includes([OpCode.CallCode, OpCode.StaticCall, OpCode.Call, OpCode.DelegateCall], structLog.op)) {
+        const isCallLike = _.includes(
+            [OpCode.CallCode, OpCode.StaticCall, OpCode.Call, OpCode.DelegateCall],
+            structLog.op,
+        );
+        const isEndOpcode = _.includes(
+            [OpCode.Return, OpCode.Stop, OpCode.Revert, OpCode.Invalid, OpCode.SelfDestruct],
+            structLog.op,
+        );
+        if (isCallLike) {
             const currentAddress = _.last(callStack) as string;
             const jumpAddressOffset = 1;
-            const newAddress = addressUtils.padZeros(
-                new BigNumber(addHexPrefix(structLog.stack[structLog.stack.length - jumpAddressOffset - 1])).toString(
-                    16,
-                ),
+            const newAddress = getAddressFromStackEntry(
+                structLog.stack[structLog.stack.length - jumpAddressOffset - 1],
             );
             if (structLog === _.last(structLogs)) {
-                throw new Error('CALL-like opcode can not be the last one');
+                throw new Error('Malformed trace. CALL-like opcode can not be the last one');
             }
             // Sometimes calls don't change the execution context (current address). When we do a transfer to an
-            // externally owned account - it does the call and immidiately returns because there is no fallback
+            // externally owned account - it does the call and immediately returns because there is no fallback
             // function. We manually check if the call depth had changed to handle that case.
             const nextStructLog = structLogs[i + 1];
             if (nextStructLog.depth !== structLog.depth) {
@@ -45,9 +55,7 @@ export function getTracesByContractAddress(structLogs: StructLog[], startAddress
                 );
                 currentTraceSegment = [];
             }
-        } else if (
-            _.includes([OpCode.Return, OpCode.Stop, OpCode.Revert, OpCode.Invalid, OpCode.SelfDestruct], structLog.op)
-        ) {
+        } else if (isEndOpcode) {
             const currentAddress = callStack.pop() as string;
             traceByContractAddress[currentAddress] = (traceByContractAddress[currentAddress] || []).concat(
                 currentTraceSegment,
@@ -81,7 +89,7 @@ export function getTracesByContractAddress(structLogs: StructLog[], startAddress
                     );
                     currentTraceSegment = [];
                 } else {
-                    throw new Error('Shit broke');
+                    throw new Error('Malformed trace. Unexpected call depth change');
                 }
             }
         }
@@ -90,7 +98,7 @@ export function getTracesByContractAddress(structLogs: StructLog[], startAddress
         throw new Error('Malformed trace. Call stack non empty at the end');
     }
     if (currentTraceSegment.length !== 0) {
-        throw new Error('Malformed trace. currentTraceSegment non empty at the end');
+        throw new Error('Malformed trace. Current trace segment non empty at the end');
     }
     return traceByContractAddress;
 }