From 4cf331067bfa2a99ea39551f9fb2ad330b1c3fb7 Mon Sep 17 00:00:00 2001
From: Alex Browne <stephenalexbrowne@gmail.com>
Date: Thu, 21 Jun 2018 13:14:13 -0700
Subject: Fix some bugs in sol-cov

---
 packages/sol-cov/src/revert_trace_subprovider.ts | 18 +++++++++++-------
 packages/sol-cov/src/utils.ts                    | 12 ++++++++++++
 2 files changed, 23 insertions(+), 7 deletions(-)

(limited to 'packages')

diff --git a/packages/sol-cov/src/revert_trace_subprovider.ts b/packages/sol-cov/src/revert_trace_subprovider.ts
index fb2215eaa..fed305bd3 100644
--- a/packages/sol-cov/src/revert_trace_subprovider.ts
+++ b/packages/sol-cov/src/revert_trace_subprovider.ts
@@ -75,6 +75,7 @@ export class RevertTraceSubprovider extends TraceCollectionSubprovider {
             }
             const bytecodeHex = stripHexPrefix(bytecode);
             const sourceMap = isContractCreation ? contractData.sourceMap : contractData.sourceMapRuntime;
+
             const pcToSourceRange = parseSourceMap(
                 contractData.sourceCodes,
                 sourceMap,
@@ -88,16 +89,19 @@ export class RevertTraceSubprovider extends TraceCollectionSubprovider {
             // actually happens in assembly). In that case, we want to keep
             // searching backwards by decrementing the pc until we find a
             // mapped source range.
-            while (_.isUndefined(sourceRange)) {
+            while (_.isUndefined(sourceRange) && pc > 0) {
                 sourceRange = pcToSourceRange[pc];
                 pc -= 1;
-                if (pc <= 0) {
-                    this._logger.warn(
-                        `could not find matching sourceRange for structLog: ${evmCallStackEntry.structLog}`,
-                    );
-                    continue;
-                }
             }
+            if (_.isUndefined(sourceRange)) {
+                this._logger.warn(
+                    `could not find matching sourceRange for structLog: ${JSON.stringify(
+                        _.omit(evmCallStackEntry.structLog, 'stack'),
+                    )}`,
+                );
+                continue;
+            }
+
             const fileIndex = contractData.sources.indexOf(sourceRange.fileName);
             const sourceSnippet = getSourceRangeSnippet(sourceRange, contractData.sourceCodes[fileIndex]);
             if (sourceSnippet !== null) {
diff --git a/packages/sol-cov/src/utils.ts b/packages/sol-cov/src/utils.ts
index d31696636..b696bd463 100644
--- a/packages/sol-cov/src/utils.ts
+++ b/packages/sol-cov/src/utils.ts
@@ -5,6 +5,10 @@ import * as _ from 'lodash';
 
 import { ContractData, LineColumn, SingleFileSourceRange } from './types';
 
+// This is the minimum length of valid contract bytecode. The Solidity compiler
+// metadata is 86 bytes. If you add the '0x' prefix, we get 88.
+const MIN_CONTRACT_BYTECODE_LENGTH = 88;
+
 export const utils = {
     compareLineColumn(lhs: LineColumn, rhs: LineColumn): number {
         return lhs.line !== rhs.line ? lhs.line - rhs.line : lhs.column - rhs.column;
@@ -38,7 +42,15 @@ export const utils = {
         }
         const contractData = _.find(contractsData, contractDataCandidate => {
             const bytecodeRegex = utils.bytecodeToBytecodeRegex(contractDataCandidate.bytecode);
+            // If the bytecode is less than the minimum length, we are probably
+            // dealing with an interface. This isn't what we're looking for.
+            if (bytecodeRegex.length < MIN_CONTRACT_BYTECODE_LENGTH) {
+                return false;
+            }
             const runtimeBytecodeRegex = utils.bytecodeToBytecodeRegex(contractDataCandidate.runtimeBytecode);
+            if (runtimeBytecodeRegex.length < MIN_CONTRACT_BYTECODE_LENGTH) {
+                return false;
+            }
             // We use that function to find by bytecode or runtimeBytecode. Those are quasi-random strings so
             // collisions are practically impossible and it allows us to reuse that code
             return !_.isNull(bytecode.match(bytecodeRegex)) || !_.isNull(bytecode.match(runtimeBytecodeRegex));
-- 
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