Devise new experimental @truffle/from-hardhat package for compatibility translation

packages/from-hardhat/.eslintrc.json

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+{
+  "extends": ["../../.eslintrc.package.json"]
+}

packages/from-hardhat/.gitignore

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+dist
+node_modules

packages/from-hardhat/README.md

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+# @truffle/from-hardhat
+
+> :warning: **This package is experimental and FOR INTERNAL USE ONLY.**
+
+This package translates Hardhat project information into Truffle's own formats.
+
+For information on using this package (until we get it more ready for public
+use), please see [`./src/api.ts`](src/api.ts).

packages/from-hardhat/package.json

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+{
+  "name": "@truffle/from-hardhat",
+  "description": "Import Hardhat project information into Truffle-native formats",
+  "license": "MIT",
+  "author": "g. nicholas d'andrea <gnidan@trufflesuite.com>",
+  "homepage": "https://github.com/trufflesuite/truffle/tree/master/packages/from-hardhat#readme",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/trufflesuite/truffle.git",
+    "directory": "packages/from-hardhat"
+  },
+  "bugs": {
+    "url": "https://github.com/trufflesuite/truffle/issues"
+  },
+  "version": "0.1.0-0",
+  "main": "dist/src/index.js",
+  "scripts": {
+    "build": "ttsc",
+    "prepare": "yarn build",
+    "test": "exit 0"
+  },
+  "dependencies": {
+    "@truffle/compile-common": "^0.7.32",
+    "@truffle/compile-solidity": "^6.0.38",
+    "@truffle/config": "^1.3.34",
+    "debug": "^4.3.1",
+    "find-up": "^2.1.0",
+    "semver": "^5.7.1"
+  },
+  "devDependencies": {
+    "@types/find-up": "^2.1.0",
+    "@types/node": "^18.6.5",
+    "hardhat": "^2.10.1",
+    "ttypescript": "1.5.13",
+    "typescript": "^4.3.5",
+    "typescript-transform-paths": "3.3.1"
+  },
+  "keywords": [
+    "ethereum",
+    "solidity",
+    "truffle",
+    "hardhat"
+  ],
+  "publishConfig": {
+    "access": "public"
+  }
+}

packages/from-hardhat/src/api.ts

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+import { promises as fs } from "fs";
+import semver from "semver";
+
+import type * as Hardhat from "hardhat/types";
+import type * as Common from "@truffle/compile-common";
+import type TruffleConfig from "@truffle/config";
+
+import {
+  supportedHardhatVersionRange,
+  supportedHardhatBuildInfoFormats
+} from "./constants";
+import * as Compilation from "./compilation";
+import * as Config from "./config";
+
+import {
+  checkHardhat,
+  askHardhatConsole,
+  askHardhatVersion
+} from "./ask-hardhat";
+import { EnvironmentOptions } from "./options";
+
+/**
+ * Checks for the existence of a Hardhat project configuration and asserts
+ * that the local installed version of Hardhat matches this package's
+ * supported version range.
+ *
+ * @param options to control process environment (e.g. working directory)
+ * @return Promise<void> when expectation holds
+ * @throws NotHardhatError when not in a Hardhat project directory
+ * @throws IncompatibleHardhatError if Hardhat has unsupported version
+ */
+export const expectHardhat = async (
+  options?: EnvironmentOptions
+): Promise<void> => {
+  const isHardhat = await checkHardhat(options);
+
+  if (!isHardhat) {
+    throw new NotHardhatError();
+  }
+
+  const hardhatVersion = await askHardhatVersion(options);
+
+  if (!semver.satisfies(hardhatVersion, supportedHardhatVersionRange)) {
+    throw new IncompatibleHardhatVersionError(hardhatVersion);
+  }
+};
+
+/**
+ * Thrown when no Hardhat project is found
+ */
+export class NotHardhatError extends Error {
+  constructor() {
+    super("Current working directory is not part of a Hardhat project");
+  }
+}
+
+/**
+ * Thrown when Hardhat was detected but with an incompatible version
+ */
+export class IncompatibleHardhatVersionError extends Error {
+  constructor(detectedVersion: string) {
+    super(
+      `Expected Hardhat version compatible with ${supportedHardhatVersionRange}, got: ${detectedVersion}`
+    );
+  }
+}
+
+/**
+ * Constructs a @truffle/config object based on the Hardhat config.
+ *
+ * WARNING: except for fields documented here, the values present on the
+ * returned @truffle/config object MUST be regarded as unsafe to use.
+ *
+ * The returned `config` is defined to contain the following:
+ *
+ *   - `config.networks` with configurations for all Hardhat-configured
+ *     networks, provided:
+ *       - The configured network is not the built-in `hardhat` network
+ *       - The configured network defines a `url` property
+ *
+ *     Note: this function ignores all properties other than `url`,
+ *     including any information that can be used for computing
+ *     cryptographic signatures. THIS FUNCTION DOES NOT READ PRIVATE KEYS.
+ *
+ * Suffice to say:
+ *
+ * THIS FUNCTION'S BEHAVIOR IS EXPERIMENTAL AND SHOULD ONLY BE USED IN
+ * SPECIFICALLY KNOWN-SUPPORTED USE CASES (like reading for configured
+ * network urls)
+ *
+ * @param options to control process environment (e.g. working directory)
+ * @return Promise<TruffleConfig>
+ *
+ * @dev This function shells out to `npx hardhat console` to ask the Hardhat
+ *      runtime environment for a fully populated config object.
+ */
+export const prepareConfig = async (
+  options?: EnvironmentOptions
+): Promise<TruffleConfig> => {
+  const hardhatConfig = (await askHardhatConsole(
+    `hre.config`,
+    options
+  )) as Hardhat.HardhatConfig;
+
+  return Config.fromHardhatConfig(hardhatConfig);
+};
+
+/**
+ * Constructs an array of @truffle/compile-common `Compilation` objects
+ * corresponding one-to-one with Hardhat's persisted results of each solc
+ * compilation.
+ *
+ * WARNING: this function only supports Hardhat projects written entirely
+ * in solc-compatible languages (Solidity, Yul). Behavior of this function
+ * for Hardhat projects using other languages is undefined.
+ *
+ * @param options to control process environment (e.g. working directory)
+ * @return Promise<Compilation[]> from @truffle/compile-common
+ *
+ * @dev This function shells out to `npx hardhat console` to ask the Hardhat
+ *      runtime environment for the location of the project build info
+ *      files
+ */
+export const prepareCompilations = async (
+  options?: EnvironmentOptions
+): Promise<Common.Compilation[]> => {
+  const compilations = [];
+
+  const buildInfoPaths = (await askHardhatConsole(
+    `artifacts.getBuildInfoPaths()`,
+    options
+  )) as string[];
+
+  for (const buildInfoPath of buildInfoPaths) {
+    const buildInfo: Hardhat.BuildInfo = JSON.parse(
+      (await fs.readFile(buildInfoPath)).toString()
+    );
+
+    const { _format } = buildInfo;
+
+    if (!supportedHardhatBuildInfoFormats.has(_format)) {
+      throw new IncompatibleHardhatBuildInfoFormatError(_format);
+    }
+
+    const compilation = Compilation.fromBuildInfo(buildInfo);
+
+    compilations.push(compilation);
+  }
+
+  return compilations;
+};
+
+/**
+ * Thrown when the build-info format detected has an incompatible version
+ */
+export class IncompatibleHardhatBuildInfoFormatError extends Error {
+  constructor(detectedFormat: string) {
+    super(
+      `Expected build-info to be one of ["${[
+        ...supportedHardhatBuildInfoFormats
+      ].join('", "')}"], got: "${detectedFormat}"`
+    );
+  }
+}

packages/from-hardhat/src/ask-hardhat.ts

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+import { spawn } from "child_process";
+
+import findUp from "find-up";
+
+import { validHardhatConfigFilenames } from "./constants";
+import { EnvironmentOptions, withDefaultEnvironmentOptions } from "./options";
+
+/**
+ * Returns a Promise to a boolean that is true if and only if
+ * the detected or specified environment is part of a Hardhat project.
+ *
+ * (i.e., if the working directory or any of its parents has a Hardhat config)
+ */
+export const checkHardhat = async (
+  options?: EnvironmentOptions
+): Promise<boolean> => {
+  const { workingDirectory } = withDefaultEnvironmentOptions(options);
+
+  // search recursively up for a hardhat config
+  const hardhatConfigPath = await findUp(validHardhatConfigFilenames, {
+    cwd: workingDirectory
+  });
+
+  return !!hardhatConfigPath;
+};
+
+/**
+ * Reads version information via `npx hardhat --version`
+ */
+export const askHardhatVersion = async (
+  options?: EnvironmentOptions
+): Promise<string> =>
+  new Promise((accept, reject) => {
+    const { workingDirectory } = withDefaultEnvironmentOptions(options);
+
+    const hardhat = spawn(`npx`, ["hardhat", "--version"], {
+      stdio: ["pipe", "pipe", "inherit"],
+      cwd: workingDirectory
+    });
+
+    let output = "";
+    hardhat.stdout.on("data", data => {
+      output = `${output}${data}`;
+    });
+
+    hardhat.once("close", code => {
+      if (code !== 0) {
+        return reject(new Error(`Hardhat exited with non-zero code ${code}`));
+      }
+
+      return accept(output);
+    });
+  });
+
+export interface AskHardhatConsoleOptions {
+  // turn off json stringify/parse
+  raw?: boolean;
+}
+
+export const askHardhatConsole = async (
+  expression: string,
+  {
+    raw = false,
+    ...options
+  }: AskHardhatConsoleOptions & EnvironmentOptions = {}
+): Promise<string | unknown> =>
+  new Promise((accept, reject) => {
+    const { workingDirectory } = withDefaultEnvironmentOptions(options);
+
+    const hardhat = spawn(`npx`, ["hardhat", "console"], {
+      stdio: ["pipe", "pipe", "inherit"],
+      cwd: workingDirectory
+    });
+
+    // we'll capture the stdout
+    let output = "";
+    hardhat.stdout.on("data", data => {
+      output = `${output}${data}`;
+    });
+
+    // setup close event before writing to stdin because we're sending eof
+    hardhat.once("close", code => {
+      if (code !== 0) {
+        return reject(new Error(`Hardhat exited with non-zero code ${code}`));
+      }
+
+      if (raw) {
+        return accept(output);
+      }
+
+      try {
+        return accept(JSON.parse(output));
+      } catch (error) {
+        return reject(error);
+      }
+    });
+
+    hardhat.stdin.write(`
+      Promise.resolve(${expression})
+        .then(${
+          raw
+            ? `console.log`
+            : `(resolved) => console.log(JSON.stringify(resolved))`
+        })
+    `);
+    hardhat.stdin.end();
+  });