Add Artifact as param option to getContractAt on ethers

Let users pass in their own `Artifact` instance to `getContractAt`, this is mainly to maintain parity with `getContractFactory`. Relates to #1716.
NomicFoundation · Dec 1, 2021 · da3dd8c · da3dd8c
1 parent 9763569
commit da3dd8c
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Showing 3 changed files with 84 additions and 28 deletions.
diff --git a/packages/hardhat-ethers/src/internal/helpers.ts b/packages/hardhat-ethers/src/internal/helpers.ts
@@ -297,46 +297,57 @@ async function getContractFactoryByAbiAndBytecode(
 
 export async function getContractAt(
   hre: HardhatRuntimeEnvironment,
-  nameOrAbi: string | any[],
+  nameOrArtifactOrAbi: string | Artifact | any[],
   address: string,
   signer?: ethers.Signer
 ) {
   const { Contract } = require("ethers") as typeof ethers;
 
-  if (typeof nameOrAbi === "string") {
-    const artifact = await hre.artifacts.readArtifact(nameOrAbi);
-    const factory = await getContractFactoryByAbiAndBytecode(
-      hre,
-      artifact.abi,
-      "0x",
-      signer
-    );
-
-    let contract = factory.attach(address);
-    // If there's no signer, we connect the contract instance to the provider for the selected network.
-    if (contract.provider === null) {
-      contract = contract.connect(hre.ethers.provider);
+  if (Array.isArray(nameOrArtifactOrAbi)) {
+    if (signer === undefined) {
+      const signers = await hre.ethers.getSigners();
+      signer = signers[0];
     }
 
-    return contract;
-  }
+    // If there's no signer, we want to put the provider for the selected network here.
+    // This allows read only operations on the contract interface.
+    const signerOrProvider: ethers.Signer | ethers.providers.Provider =
+      signer !== undefined ? signer : hre.ethers.provider;
 
-  if (signer === undefined) {
-    const signers = await hre.ethers.getSigners();
-    signer = signers[0];
+    const abiWithAddedGas = addGasToAbiMethodsIfNecessary(
+      hre.network.config,
+      nameOrArtifactOrAbi
+    );
+
+    return new Contract(address, abiWithAddedGas, signerOrProvider);
   }
 
-  // If there's no signer, we want to put the provider for the selected network here.
-  // This allows read only operations on the contract interface.
-  const signerOrProvider: ethers.Signer | ethers.providers.Provider =
-    signer !== undefined ? signer : hre.ethers.provider;
+  let artifact: Artifact;
+  if (typeof nameOrArtifactOrAbi === "string") {
+    artifact = await hre.artifacts.readArtifact(nameOrArtifactOrAbi);
+  } else if (isArtifact(nameOrArtifactOrAbi)) {
+    artifact = nameOrArtifactOrAbi;
+  } else {
+    throw new NomicLabsHardhatPluginError(
+      pluginName,
+      "Bad parameter passed to `getContractAt`"
+    );
+  }
 
-  const abiWithAddedGas = addGasToAbiMethodsIfNecessary(
-    hre.network.config,
-    nameOrAbi
+  const factory = await getContractFactoryByAbiAndBytecode(
+    hre,
+    artifact.abi,
+    "0x",
+    signer
   );
 
-  return new Contract(address, abiWithAddedGas, signerOrProvider);
+  let contract = factory.attach(address);
+  // If there's no signer, we connect the contract instance to the provider for the selected network.
+  if (contract.provider === null) {
+    contract = contract.connect(hre.ethers.provider);
+  }
+
+  return contract;
 }
 
 // This helper adds a `gas` field to the ABI function elements if the network

diff --git a/packages/hardhat-ethers/src/types/index.ts b/packages/hardhat-ethers/src/types/index.ts
@@ -28,7 +28,7 @@ export interface HardhatEthersHelpers {
 
   getContractFactory: typeof getContractFactory;
   getContractAt: (
-    nameOrAbi: string | any[],
+    nameOrAbi: string | Artifact | any[],
     address: string,
     signer?: ethers.Signer
   ) => Promise<ethers.Contract>;

diff --git a/packages/hardhat-ethers/test/index.ts b/packages/hardhat-ethers/test/index.ts
@@ -664,6 +664,51 @@ describe("Ethers plugin", function () {
           });
         });
 
+        describe("by artifact and address", function () {
+          it("Should return an instance of a contract", async function () {
+            const contract = await this.env.ethers.getContractAt(
+              greeterArtifact,
+              deployedGreeter.address
+            );
+
+            assert.containsAllKeys(contract.functions, [
+              "setGreeting(string)",
+              "greet()",
+            ]);
+
+            assert.equal(
+              await contract.signer.getAddress(),
+              await signers[0].getAddress()
+            );
+          });
+
+          it("Should be able to send txs and make calls", async function () {
+            const greeter = await this.env.ethers.getContractAt(
+              greeterArtifact,
+              deployedGreeter.address
+            );
+
+            assert.equal(await greeter.functions.greet(), "Hi");
+            await greeter.functions.setGreeting("Hola");
+            assert.equal(await greeter.functions.greet(), "Hola");
+          });
+
+          describe("with custom signer", function () {
+            it("Should return an instance of a contract associated to a custom signer", async function () {
+              const contract = await this.env.ethers.getContractAt(
+                greeterArtifact,
+                deployedGreeter.address,
+                signers[1]
+              );
+
+              assert.equal(
+                await contract.signer.getAddress(),
+                await signers[1].getAddress()
+              );
+            });
+          });
+        });
+
         describe("by abi and address", function () {
           it("Should return an instance of a contract", async function () {
             const contract = await this.env.ethers.getContractAt(