Track gas deltas

README.md

@@ -76,6 +76,7 @@ const config: HardhatUserConfig = {
 
 | Options                         |    Type    |   Default  | Description                                                                                                                                                                                                                                                         |
 | :------------------------------ | :--------: | :--------: | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| checkGasDeltas                  |  _bool_  |    `false`   | Compare gas values to previous results                                                                                                     |
 | currency                        |  _string_  |    `USD`   | National currency to represent gas costs in. Exchange rates are loaded at runtime from the `coinmarketcap` api. Available currency codes can be found [here][5]                                                                                                     |
 | coinmarketcap                   |  _string_  |      -     | [API key][3] to use when fetching live token price data                                                                                                                                                                                                             |
 | enabled                         |   _bool_   |   `true`   | Produce gas reports with `hardhat test`                                                                                                                                                                                                                             |

src/constants.ts

@@ -21,6 +21,8 @@ export const DEFAULT_ARBITRUM_HARDFORK = "arbOS11";
 export const TOOLCHAIN_HARDHAT = "hardhat";
 export const TOOLCHAIN_FOUNDRY = "foundry";
 
+export const CACHE_FILE_NAME = ".hardhat_gas_reporter_output.json";
+
 // EVM
 export const EVM_BASE_TX_COST = 21000;
 export const DEFAULT_BLOB_BASE_FEE = 10; // gwei

src/lib/gasData.ts

@@ -106,6 +106,35 @@ export class GasData {
     }
   }
 
+  /**
+   * Calculate gas deltas compared to previous data, if applicable
+   * @param  {GasData} previousData previous gas data
+   */
+  public addDeltas(previousData: GasData) {
+    Object.keys(this.methods).forEach(key => {
+        if (!previousData.methods[key]) return;
+
+        const currentMethod = this.methods[key];
+        const prevMethod = previousData.methods[key];
+
+        if (currentMethod.min !== undefined && prevMethod.min !== undefined) {
+          currentMethod.minDelta = currentMethod.min! - prevMethod.min!;
+        }
+
+        if (currentMethod.max !== undefined && prevMethod.max !== undefined) {
+          currentMethod.maxDelta = currentMethod.max! - prevMethod.max!;
+        }
+
+        if (currentMethod.executionGasAverage !== undefined && prevMethod.executionGasAverage !== undefined) {
+          currentMethod.executionGasAverageDelta = currentMethod.executionGasAverage! - prevMethod.executionGasAverage!;
+        }
+
+        if (currentMethod.calldataGasAverage !== undefined && prevMethod.calldataGasAverage !== undefined) {
+          currentMethod.calldataGasAverageDelta = currentMethod.calldataGasAverage! - prevMethod.calldataGasAverage!;
+        }
+     })
+  }
+
   /**
    * Map a contract name to pre-generated hash of the code stored at an address
    * @param  {String} name    contract name

src/lib/render/index.ts

@@ -1,19 +1,21 @@
 import type { GasData } from "../gasData";
 import { writeFileSync } from "fs";
+import path from "path";
 
 import { HardhatRuntimeEnvironment as HRE } from "hardhat/types";
 import {
   TABLE_NAME_LEGACY,
   TABLE_NAME_MARKDOWN,
-  TABLE_NAME_TERMINAL
+  TABLE_NAME_TERMINAL,
+  CACHE_FILE_NAME
 } from "../../constants";
 import { getSolcInfo } from "../../utils/sources";
 import { warnReportFormat } from "../../utils/ui";
 import { GasReporterOptions } from "../../types";
 import { generateTerminalTextTable } from "./terminal";
 import { generateLegacyTextTable } from "./legacy";
 import { generateMarkdownTable} from "./markdown";
-import { generateJSONData } from "./json";
+import { generateJSONData, loadJSONCache } from "./json";
 
 
 /**
@@ -55,6 +57,18 @@ export function render(
   options.blockGasLimit = hre.__hhgrec.blockGasLimit;
   options.solcInfo = getSolcInfo(hre.config.solidity.compilers[0]);
 
+  if (options.checkGasDeltas) {
+    options.cachePath = options.cachePath || path.resolve(
+      hre.config.paths.cache,
+      CACHE_FILE_NAME
+    );
+
+    try {
+      const previousData = loadJSONCache(options);
+      data.addDeltas(previousData.data!);
+    } catch {};
+  }
+
 
   // Get table
   let table = getTableForFormat(hre, data, options, toolchain);
@@ -106,6 +120,11 @@ export function render(
     generateJSONData(data, options, toolchain);
   }
 
+  if (options.checkGasDeltas) {
+    options.outputJSONFile = options.cachePath!;
+    generateJSONData(data, options, toolchain);
+  }
+
   // Write warnings
   for (const warning of warnings) console.log(warning);
 }

src/lib/render/json.ts

@@ -1,4 +1,4 @@
-import { writeFileSync } from "fs";
+import { writeFileSync, readFileSync } from "fs";
 import { GasData } from "../gasData";
 import { GasReporterOptions, GasReporterOutput } from "../../types";
 
@@ -28,6 +28,17 @@ export function generateJSONData(
   writeFileSync(options.outputJSONFile!, JSON.stringify(output, null, ' '));
 }
 
+/**
+ * Reads previous acccumulated data and options from cache so it can be used to calculate deltas
+ * @param {GasReporterOptions} options
+ * @returns {GasReporterOptions} previous data and options
+ */
+export function loadJSONCache(
+  options: GasReporterOptions
+): GasReporterOutput {
+  return JSON.parse(readFileSync(options.cachePath!).toString());
+}
+
 /**
  * Removes extraneous data and attached methods
  * @param {GasData} data

src/lib/render/markdown.ts

@@ -12,7 +12,8 @@ import {
   entitleMarkdown,
   getCommonTableVals,
   costIsBelowPrecision,
-  markdownBold
+  markdownBold,
+  renderWithGasDelta
 } from "../../utils/ui";
 
 import { GasReporterOptions, MethodDataItem } from "../../types";
@@ -135,6 +136,11 @@ export function generateMarkdownTable(
           ? "-"
           : commify(method.calldataGasAverage);
       };
+
+      if (options.checkGasDeltas) {
+        stats.executionGasAverage = renderWithGasDelta(stats.executionGasAverage, method.executionGasAverageDelta || 0);
+        stats.calldataGasAverage = renderWithGasDelta(stats.calldataGasAverage, method.calldataGasAverageDelta || 0);
+      }
     } else {
       stats.executionGasAverage = "-";
       stats.cost = "-";
@@ -146,8 +152,14 @@ export function generateMarkdownTable(
 
     if (method.min && method.max) {
       const uniform = (method.min === method.max);
-      stats.min = uniform ? "-" : commify(method.min!);
-      stats.max = uniform ? "-" : commify(method.max!);
+      let min = commify(method.min!);
+      let max = commify(method.max!)
+      if (options.checkGasDeltas) {
+        min = renderWithGasDelta(min, method.minDelta || 0);
+        max = renderWithGasDelta(max, method.maxDelta || 0);
+      }
+      stats.min = uniform ? "-" : min;
+      stats.max = uniform ? "-" : max;
     }
 
     stats.numberOfCalls = method.numberOfCalls.toString();

src/lib/render/terminal.ts

@@ -10,7 +10,8 @@ import {
   getCommonTableVals,
   indentText,
   indentTextWithSymbol,
-  costIsBelowPrecision
+  costIsBelowPrecision,
+  renderWithGasDelta
 } from "../../utils/ui";
 
 import { GasReporterOptions, MethodDataItem } from "../../types";
@@ -106,6 +107,10 @@ export function generateTerminalTextTable(
         ?  commify(method.calldataGasAverage)
         : chalk.grey("-");
 
+        if (options.checkGasDeltas) {
+          stats.executionGasAverage = renderWithGasDelta(stats.executionGasAverage, method.executionGasAverageDelta || 0, true);
+          stats.calldataGasAverage = renderWithGasDelta(stats.calldataGasAverage, method.calldataGasAverageDelta || 0, true);
+        }
     } else {
       stats.executionGasAverage = chalk.grey("-");
       stats.cost = chalk.grey("-");
@@ -117,8 +122,14 @@ export function generateTerminalTextTable(
 
     if (method.min && method.max) {
       const uniform = (method.min === method.max);
-      stats.min = uniform ? chalk.grey("-") : chalk.cyan(commify(method.min!));
-      stats.max = uniform ? chalk.grey("-") : chalk.red(commify(method.max!));
+      let min = chalk.cyan(commify(method.min!));
+      let max = chalk.red(commify(method.max!));
+      if (options.checkGasDeltas) {
+        min = renderWithGasDelta(min, method.minDelta || 0, true);
+        max = renderWithGasDelta(max, method.maxDelta || 0, true);
+      }
+      stats.min = uniform ? chalk.grey("-") : min;
+      stats.max = uniform ? chalk.grey("-") : max;
     }
 
     const fnName = options.showMethodSig ? method.fnSig : method.method;

src/types.ts

@@ -36,6 +36,9 @@ export interface GasReporterOptions {
   /** @property Etherscan-like url to fetch blobBasefee from */
   blobBaseFeeApi?: string;
 
+  /** @property Compare gas values to previous results */
+  checkGasDeltas?: boolean;
+
   /** @property API key to access token/currency market price data with */
   coinmarketcap?: string;
 
@@ -155,6 +158,9 @@ export interface GasReporterOptions {
 
   /** @ignore */
   blockGasLimit?: number;
+
+  /** @ignore */
+  cachePath?: string;
 }
 
 export interface GasReporterExecutionContext {
@@ -214,6 +220,10 @@ export interface MethodDataItem {
   executionGasAverage?: number,
   calldataGasAverage?: number,
   cost?: string,
+  minDelta?: number,
+  maxDelta?: number,
+  executionGasAverageDelta? :number
+  calldataGasAverageDelta?: number,
 }
 
 export interface MethodData {[key: string]: MethodDataItem }

src/utils/ui.ts

@@ -1,5 +1,6 @@
 import chalk from "chalk";
 import { EOL } from "os";
+import { commify } from "@ethersproject/units";
 
 import {
   DEFAULT_GAS_PRICE_PRECISION,
@@ -39,6 +40,18 @@
   return `*${val}*`
 }
 
+export function renderWithGasDelta(val: string, delta: number, withColor?: boolean) {
+  if (delta == 0) return val;
+
+  let deltaString = commify(delta);
+  if (withColor) {
+    deltaString = delta > 0 ? chalk.redBright(`+${deltaString}`) : chalk.green(`${deltaString}`);
+  } else {
+    deltaString = delta > 0 ? `+${deltaString}` : `${deltaString}`;
+  }
+  return `${val} ${deltaString}`;
+}
+
 export function getSmallestPrecisionVal(precision: number): number {
   let start = "."
   for (let i = 0; i < precision - 1; i++ ) {

test/integration/options.a.ts

@@ -17,6 +17,7 @@ import { useEnvironment, findMethod, findDeployment } from "../helpers";
  * + Display full method signature
  * + Dark mode
  * + RST titles
+ * + Gas deltas
  */
 describe("Options A", function () {
   let output: GasReporterOutput;
@@ -87,4 +88,25 @@ describe("Options A", function () {
     assert.equal(methodA?.numberOfCalls, 1);
     assert.equal(methodB?.numberOfCalls, 1);
   });
+
+  it("calculates gas deltas for method calls", async function(){
+    process.env.GAS_DELTA = "true";
+    await this.env.run(TASK_TEST, { testFiles: [] });
+    process.env.GAS_DELTA = "";
+
+    const _output = JSON.parse(readFileSync(options.cachePath!, 'utf-8'));
+    const _methods = _output.data!.methods;
+    const _options = _output.options;
+
+    const method = findMethod(_methods, "VariableCosts", "addToMap");
+
+    if (_options.cachePath) {
+      try {
+        execSync(`rm ${_options.cachePath}`)
+      } catch {}
+    }
+
+    assert.isNumber(method!.executionGasAverageDelta!);
+    assert.notEqual(method!.executionGasAverageDelta!, 0);
+  });
 });

test/projects/options/hardhat.options.a.config.ts

@@ -44,7 +44,8 @@ const config: HardhatUserConfig = {
     enabled: true,
     darkMode: true,
     proxyResolver: new EtherRouterResolver(),
-    includeBytecodeInJSON: true
+    includeBytecodeInJSON: true,
+    checkGasDeltas: true
   }
 };
 

test/projects/options/test/variablecosts.ts

@@ -5,7 +5,7 @@ import { Contract } from "ethers";
 
 describe("VariableCosts", function() {
   const one = [1];
-  const three = [2, 3, 4];
+  const three = process.env.GAS_DELTA === "true" ? [2, 3, 4, 5, 6, 7, 8] : [2, 3, 4]; // changing gas values if required
   const five = [5, 6, 7, 8, 9];
   let instance: Contract;
   let walletB: any;