fix: Allow block time offset to be negative (#663)

* fix: Allow block time offset to be negative

* Add a changeset file

* fix: Use a correct sign for block time offset

* test: Add a regression test for forking blocks with future timestamps

.changeset/hungry-cats-enjoy.md

@@ -0,0 +1,5 @@
+---
+"@nomicfoundation/edr": patch
+---
+
+Allow forked block time offset to be negative

crates/edr_provider/src/data.rs

@@ -2691,11 +2691,13 @@ fn create_blockchain_and_state(
                         .timestamp,
                 );
 
-            let elapsed_time = timer
-                .since(fork_block_timestamp)
-                .expect("current time must be after fork block");
+            let elapsed = match timer.since(fork_block_timestamp) {
+                Ok(elapsed) => -i128::from(elapsed),
+                Err(forward_drift) => i128::from(forward_drift.duration().as_secs()),
+            };
 
-            -i64::try_from(elapsed_time)
+            elapsed
+                .try_into()
                 .expect("Elapsed time since fork block must be representable as i64")
         };
 

crates/edr_provider/src/time.rs

@@ -42,7 +42,7 @@ mod test_utils {
 
     use super::{CurrentTime, TimeSinceEpoch};
 
-    /// An internally mutable mock implementation of `TimeSinceEpoch`.
+    /// An internally mutable mock implementation of [`TimeSinceEpoch`].
     #[derive(Debug)]
     pub struct MockTime(AtomicU64);
 

crates/edr_provider/tests/issues/issue_588.rs

@@ -0,0 +1,36 @@
+//! Allow forking blocks with future timestamps.
+//!
+//! See <https://github.com/NomicFoundation/edr/issues/588>
+
+use std::sync::Arc;
+
+use edr_provider::{
+    hardhat_rpc_types::ForkConfig, test_utils::create_test_config_with_fork, time::MockTime,
+    NoopLogger, Provider,
+};
+use edr_test_utils::env::get_alchemy_url;
+use tokio::runtime;
+
+#[tokio::test(flavor = "multi_thread")]
+async fn issue_588() -> anyhow::Result<()> {
+    let logger = Box::new(NoopLogger);
+    let subscriber = Box::new(|_event| {});
+
+    let early_mainnet_fork = create_test_config_with_fork(Some(ForkConfig {
+        json_rpc_url: get_alchemy_url(),
+        block_number: Some(2_675_000),
+        http_headers: None,
+    }));
+
+    let current_time_is_1970 = Arc::new(MockTime::with_seconds(0));
+
+    let _forking_succeeds = Provider::new(
+        runtime::Handle::current(),
+        logger,
+        subscriber,
+        early_mainnet_fork,
+        current_time_is_1970,
+    )?;
+
+    Ok(())
+}

crates/edr_provider/tests/issues/mod.rs

@@ -11,3 +11,4 @@ mod issue_407;
 mod issue_503;
 mod issue_533;
 mod issue_570;
+mod issue_588;