Stop looping on self-referencing contracts (#26)

* Change null to undefined

* Stop looping on self-referencing contracts

* Update package.json

Co-authored-by: Kris Kaczor <[email protected]>

Co-authored-by: Kris Kaczor <[email protected]>

Author: hasparus

package.json

@@ -9,7 +9,8 @@
     "lint": "eslint --ext .ts ./packages/*/src/**/*.ts",
     "lint:fix": "pnpm lint -- --fix",
     "prepare-deploy": "cp ./vercel.json ./packages/vscode-host/dist",
-    "test": "mocha"
+    "test": "mocha",
+    "check": "pnpm test && pnpm lint"
   },
   "devDependencies": {
     "@types/jsdom": "^16.2.14",

packages/ethereum-viewer/src/addresses.ts

@@ -1,4 +1,6 @@
 export const addresses = {
   L1ChugSplashProxy: "0x99c9fc46f92e8a1c0dec1b1747d010903e884be1",
   DAI: "0x6b175474e89094c44da98b954eedeac495271d0f",
+  NonfungiblePositionManager: "0xc36442b4a4522e871399cd717abdd847ab11fe88",
+  UniswapV3Router: "0xe592427a0aece92de3edee1f18e0157c05861564",
 };

packages/ethereum-viewer/src/explorer/fetchFiles.ts

@@ -6,10 +6,22 @@ import { prettyStringify } from "../util/stringify";
 import * as types from "./api-types";
 import { ApiName, explorerApiKeys, explorerApiUrls } from "./networks";
 
+interface FetchFilesOptions {
+  /**
+   * For unit testing.
+   * @internal
+   */
+  fetch?: typeof _fetch;
+  /**
+   * If more than 0, we fetch implementation contract and merge its files.
+   */
+  proxyDepth?: number;
+}
+
 export async function fetchFiles(
   apiName: ApiName,
   contractAddress: string,
-  fetch: typeof _fetch = _fetch
+  { fetch = _fetch, proxyDepth = 3 }: FetchFilesOptions = {}
 ): Promise<FetchFilesResult> {
   const apiUrl = explorerApiUrls[apiName];
   const url =
@@ -71,8 +83,16 @@ export async function fetchFiles(
     files[info.ContractName + ".sol"] = sourceCode;
   }
 
-  if (implementationAddr) {
-    const implementation = await fetchFiles(apiName, implementationAddr);
+  if (
+    implementationAddr &&
+    proxyDepth > 0 &&
+    implementationAddr !== contractAddress
+  ) {
+    const implementation = await fetchFiles(apiName, implementationAddr, {
+      fetch,
+      proxyDepth: proxyDepth - 1,
+    });
+
     Object.assign(
       files,
       prefixFiles(implementation.files, implementation.info.ContractName)

packages/ethereum-viewer/src/extension.ts

@@ -1,4 +1,5 @@
 import * as vscode from "vscode";
+import { addresses } from "./addresses";
 
 import { registerContributedCommands } from "./contributedCommands";
 import { executeHostCommand } from "./executeHostCommand";
@@ -34,7 +35,7 @@ async function main(context: vscode.ExtensionContext) {
     name: network,
   });
 
-  let address: string | null = null;
+  let address: string | undefined;
 
   if (IN_DETH_HOST) address = await executeHostCommand("getContractAddress");
 
@@ -49,7 +50,7 @@ async function detectExplorerApiName(): Promise<explorer.ApiName> {
   if (IN_DETH_HOST) {
     const detectedName = await executeHostCommand("getApiName");
 
-    if (detectedName === null) return "etherscan";
+    if (!detectedName) return "etherscan";
 
     if (!(detectedName in explorerApiUrls)) {
       await vscode.window.showErrorMessage(

…thereum-viewer/src/test/explorer.test.ts …ereum-viewer/src/test/fetchFiles.test.tspackages/ethereum-viewer/src/test/explorer.test.ts renamed to packages/ethereum-viewer/src/test/fetchFiles.test.ts packages/ethereum-viewer/src/test/explorer.test.ts renamed to packages/ethereum-viewer/src/test/fetchFiles.test.ts

@@ -33,7 +33,7 @@ describe(fetchFiles.name, () => {
       };
     };
 
-    await fetchFiles("optimistic.etherscan", "0x0", f);
+    await fetchFiles("optimistic.etherscan", "0x0", { fetch: f });
 
     const expected =
       "https://api-optimistic.etherscan.io/api?module=contract&action=getsourcecode&address=0x0&apikey=862Y3WJ4JB4B34PZQRFEV3IK6SZ8GNR9N5";
@@ -69,7 +69,7 @@ describe(fetchFiles.name, () => {
       };
     };
 
-    const { files } = await fetchFiles("etherscan", "0x0", f);
+    const { files } = await fetchFiles("etherscan", "0x0", { fetch: f });
 
     const expected =
       "Oops! It seems this contract source code is not verified on https://etherscan.io.";
@@ -78,4 +78,94 @@ describe(fetchFiles.name, () => {
       `Expected ${files["error.md"]} to contain ${expected}`
     );
   });
+
+  it("does not fall into infinite recursion when contract has itself as implementation", async () => {
+    const addr = "0xc36442b4a4522e871399cd717abdd847ab11fe88";
+    let callsCounter = 0;
+    const f = async (): Promise<ContractSourceResponse> => {
+      callsCounter++;
+      return {
+        status: "1",
+        message: "OK",
+        result: [
+          {
+            SourceCode: "// woop",
+            ABI: "[]",
+            ContractName: "ImplementsItself",
+            CompilerVersion: "v0.7.6+commit.7338295f",
+            OptimizationUsed: "1",
+            Runs: "2000",
+            ConstructorArguments: "",
+            EVMVersion: "Default",
+            Library: "",
+            LicenseType: "",
+            Proxy: "1",
+            Implementation: addr,
+            SwarmSource: "",
+          },
+        ],
+      };
+    };
+
+    await fetchFiles("etherscan", addr, { fetch: f });
+
+    assert(
+      callsCounter === 1,
+      `fetchFiles should have been called once, but was called ${callsCounter} times`
+    );
+  });
+
+  it("does not follow .Implementation without end", async () => {
+    const makeContract = ({
+      Implementation,
+    }: {
+      Implementation: string;
+    }): ContractSourceResponse => ({
+      status: "1",
+      message: "OK",
+      result: [
+        {
+          SourceCode: "//",
+          ABI: "[]",
+          ContractName: "ImplementsItself",
+          CompilerVersion: "v0.7.6+commit.7338295f",
+          OptimizationUsed: "1",
+          Runs: "2000",
+          ConstructorArguments: "",
+          EVMVersion: "Default",
+          Library: "",
+          LicenseType: "",
+          Proxy: "1",
+          Implementation: Implementation,
+          SwarmSource: "",
+        },
+      ],
+    });
+
+    const contracts = {
+      "0x00": makeContract({ Implementation: "0x01" }),
+      "0x01": makeContract({ Implementation: "0x02" }),
+      "0x02": makeContract({ Implementation: "0x03" }),
+      "0x03": makeContract({ Implementation: "0x04" }),
+      "0x04": makeContract({ Implementation: "0x05" }),
+    };
+
+    const fetchedAddresses: string[] = [];
+    const f = async (url: string): Promise<ContractSourceResponse> => {
+      const address = new URL(url).searchParams.get("address")!;
+
+      fetchedAddresses.push(address);
+
+      return contracts[address as keyof typeof contracts];
+    };
+
+    await fetchFiles("etherscan", "0x00", { fetch: f });
+
+    const actual = JSON.stringify(fetchedAddresses);
+    const expected = JSON.stringify(["0x00", "0x01", "0x02", "0x03"]);
+    assert(
+      actual === expected,
+      `Actual: ${actual}\n` + `Expected: ${expected}`
+    );
+  });
 });

packages/vscode-host/src/deth/commands/ethViewerCommands.ts

@@ -1,7 +1,7 @@
 export const ethViewerCommands = {
   getBrowserUrl: () => window.location.href,
   replaceBrowserUrl: (url: string) => window.location.replace(url),
-  getContractAddress: (): string | null => {
+  getContractAddress: (): string | undefined => {
     const url = new URL(window.location.href);
 
     // surge.sh doesn't seem to support rewrites, so we also read from search params.
@@ -14,14 +14,16 @@ export const ethViewerCommands = {
     if (path.startsWith("token/")) path = path.slice(6);
     if (path.endsWith("/")) path = path.slice(0, -1);
 
-    return path.startsWith("0x") ? path : null;
+    return path.startsWith("0x") ? path : undefined;
   },
-  getApiName: (): string | null => {
+  getApiName: (): string | undefined => {
     const { hostname } = window.location;
 
     if (hostname.endsWith(".deth.net")) return hostname.slice(0, -9);
 
-    return new URLSearchParams(window.location.search).get("explorer");
+    return (
+      new URLSearchParams(window.location.search).get("explorer") || undefined
+    );
   },
   openRepoOnGithub: () => {
     window.open("https://github.com/dethcrypto/ethereum-code-viewer", "_blank");