feat: add anvil_snapshot/anvil_revert (#432)

SUPPORTED_APIS.md

@@ -14,6 +14,8 @@ The `status` options are:
 
 | Namespace | API | <div style="width:130px">Status</div> | Description |
 | --- | --- | --- | --- |
+| `ANVIL` | `anvil_snapshot` | `SUPPORTED` | Snapshot the state of the blockchain at the current block |
+| `ANVIL` | `anvil_revert` | `SUPPORTED` | Revert the state of the blockchain to a previous snapshot |
 | `ANVIL` | `anvil_setTime` | `SUPPORTED` | Sets the internal clock time to the given timestamp |
 | `ANVIL` | `anvil_increaseTime` | `SUPPORTED` | Jump forward in time by the given amount of time, in seconds |
 | `ANVIL` | `anvil_setNextBlockTimestamp` | `SUPPORTED` | Works like `anvil_increaseTime`, but takes the exact timestamp that you want in the next block, and increases the time accordingly |

e2e-tests/test/anvil-apis.test.ts

@@ -10,6 +10,43 @@ import { BigNumber } from "ethers";
 
 const provider = getTestProvider();
 
+describe("anvil_snapshot", function () {
+  it("Should return incrementing snapshot ids", async function () {
+    const wallet = new Wallet(RichAccounts[6].PrivateKey);
+    const deployer = new Deployer(hre, wallet);
+    const greeter = await deployContract(deployer, "Greeter", ["Hi"]);
+    expect(await greeter.greet()).to.eq("Hi");
+
+    // Act
+    const snapshotId1: string = await provider.send("anvil_snapshot", []);
+    const snapshotId2: string = await provider.send("anvil_snapshot", []);
+
+    // Assert
+    expect(await greeter.greet()).to.eq("Hi");
+    expect(BigNumber.from(snapshotId2).toString()).to.eq(BigNumber.from(snapshotId1).add(1).toString());
+  });
+});
+
+describe("anvil_revert", function () {
+  it("Should revert with correct snapshot id", async function () {
+    const wallet = new Wallet(RichAccounts[6].PrivateKey);
+    const deployer = new Deployer(hre, wallet);
+    const greeter = await deployContract(deployer, "Greeter", ["Hi"]);
+    expect(await greeter.greet()).to.eq("Hi");
+    const snapshotId = await provider.send("anvil_snapshot", []);
+    const setGreetingTx = await greeter.setGreeting("Hola, mundo!");
+    await setGreetingTx.wait();
+    expect(await greeter.greet()).to.equal("Hola, mundo!");
+
+    // Act
+    const reverted: boolean = await provider.send("anvil_revert", [snapshotId]);
+
+    // Assert
+    expect(await greeter.greet()).to.eq("Hi");
+    expect(reverted).to.be.true;
+  });
+});
+
 describe("anvil_increaseTime", function () {
   it("Should increase current timestamp of the node", async function () {
     // Arrange

src/namespaces/anvil.rs

@@ -6,6 +6,29 @@ use crate::utils::Numeric;
 
 #[rpc]
 pub trait AnvilNamespaceT {
+    /// Snapshot the state of the blockchain at the current block. Takes no parameters. Returns the id of the snapshot
+    /// that was created. A snapshot can only be reverted once. After a successful `anvil_revert`, the same snapshot id cannot
+    /// be used again. Consider creating a new snapshot after each `anvil_revert` if you need to revert to the same
+    /// point multiple times.
+    ///
+    /// # Returns
+    /// The `U64` identifier for this snapshot.
+    #[rpc(name = "anvil_snapshot")]
+    fn snapshot(&self) -> RpcResult<U64>;
+
+    /// Revert the state of the blockchain to a previous snapshot. Takes a single parameter,
+    /// which is the snapshot id to revert to. This deletes the given snapshot, as well as any snapshots
+    /// taken after (e.g.: reverting to id 0x1 will delete snapshots with ids 0x1, 0x2, etc.)
+    ///
+    /// # Arguments
+    ///
+    /// * `id` - The snapshot id to revert
+    ///
+    /// # Returns
+    /// `true` if a snapshot was reverted, otherwise `false`.
+    #[rpc(name = "anvil_revert")]
+    fn revert(&self, id: U64) -> RpcResult<bool>;
+
     /// Set the current timestamp for the node.
     /// Warning: This will allow you to move backwards in time, which may cause new blocks to appear to be
     /// mined before old blocks. This will result in an invalid state.

src/node/anvil.rs

@@ -12,6 +12,24 @@ use crate::{
 impl<S: ForkSource + std::fmt::Debug + Clone + Send + Sync + 'static> AnvilNamespaceT
     for InMemoryNode<S>
 {
+    fn snapshot(&self) -> RpcResult<U64> {
+        self.snapshot()
+            .map_err(|err| {
+                tracing::error!("failed creating snapshot: {:?}", err);
+                into_jsrpc_error(Web3Error::InternalError(err))
+            })
+            .into_boxed_future()
+    }
+
+    fn revert(&self, id: U64) -> RpcResult<bool> {
+        self.revert_snapshot(id)
+            .map_err(|err| {
+                tracing::error!("failed reverting snapshot: {:?}", err);
+                into_jsrpc_error(Web3Error::InternalError(err))
+            })
+            .into_boxed_future()
+    }
+
     fn set_time(&self, timestamp: Numeric) -> RpcResult<i128> {
         self.set_time(timestamp)
             .map_err(|err| {