Improve error messages when unable to find bytecode

packages/sol-trace/CHANGELOG.json

@@ -1,4 +1,13 @@
 [
+    {
+        "version": "2.0.1",
+        "changes": [
+            {
+                "note": "Improve error messages when unable to find matching bytecode",
+                "pr": 1558
+            }
+        ]
+    },
     {
         "version": "2.0.0",
         "changes": [

packages/sol-trace/package.json

@@ -32,6 +32,7 @@
         "@0x/sol-tracing-utils": "^4.0.1",
         "@0x/subproviders": "^2.1.11",
         "@0x/typescript-typings": "^3.0.8",
+        "chalk": "^2.3.0",
         "ethereum-types": "^1.1.6",
         "ethereumjs-util": "^5.1.1",
         "lodash": "^4.17.5",

packages/sol-trace/src/revert_trace_subprovider.ts

@@ -11,6 +11,7 @@ import {
     TraceCollectionSubprovider,
     utils,
 } from '@0x/sol-tracing-utils';
+import chalk from 'chalk';
 import { stripHexPrefix } from 'ethereumjs-util';
 import * as _ from 'lodash';
 import { getLogger, levels, Logger } from 'loglevel';
@@ -71,9 +72,21 @@ export class RevertTraceSubprovider extends TraceCollectionSubprovider {
             const bytecode = await this._web3Wrapper.getContractCodeAsync(evmCallStackEntry.address);
             const contractData = utils.getContractDataIfExists(this._contractsData, bytecode);
             if (_.isUndefined(contractData)) {
+                const shortenHex = (hex: string) => {
+                    /**
+                     * Length chooses so that both error messages are of the same length
+                     * and it's enough data to figure out which artifact has a problem.
+                     */
+                    const length = 18;
+                    return `${hex.substr(0, length + 2)}...${hex.substr(hex.length - length, length)}`;
+                };
                 const errMsg = isContractCreation
-                    ? `Unknown contract creation transaction`
-                    : `Transaction to an unknown address: ${evmCallStackEntry.address}`;
+                    ? `Unable to find matching bytecode for contract creation ${chalk.bold(
+                          shortenHex(bytecode),
+                      )}, please check your artifacts. Ignoring...`
+                    : `Unable to find matching bytecode for contract address ${chalk.bold(
+                          evmCallStackEntry.address,
+                      )}, please check your artifacts. Ignoring...`;
                 this._logger.warn(errMsg);
                 continue;
             }