Do not panic while panicking

primitives/runtime/src/lib.rs

@@ -795,7 +795,10 @@ impl SignatureBatching {
 impl Drop for SignatureBatching {
 	fn drop(&mut self) {
 		// Sanity check. If user forgets to actually call `verify()`.
-		if !self.0 {
+		//
+		// We should not panic if the current thread is already panicking,
+		// because Rust otherwise aborts the process.
+		if !self.0 && !sp_std::thread::panicking() {
 			panic!("Signature verification has not been called before `SignatureBatching::drop`")
 		}
 	}
@@ -885,4 +888,18 @@ mod tests {
 			);
 		});
 	}
+
+	#[test]
+	#[should_panic(expected = "Hey, I'm an error")]
+	fn batching_does_not_panic_while_thread_is_already_panicking() {
+		let mut ext = sp_state_machine::BasicExternalities::default();
+		ext.register_extension(
+			sp_core::traits::TaskExecutorExt::new(sp_core::testing::TaskExecutor::new()),
+		);
+
+		ext.execute_with(|| {
+			let _batching = SignatureBatching::start();
+			panic!("Hey, I'm an error");
+		});
+	}
 }

primitives/std/with_std.rs

@@ -44,3 +44,7 @@ pub mod collections {
 	pub use std::collections::btree_set;
 	pub use std::collections::vec_deque;
 }
+
+pub mod thread {
+	pub use std::thread::panicking;
+}

primitives/std/without_std.rs

@@ -53,3 +53,12 @@ pub mod borrow {
 	pub use core::borrow::*;
 	pub use alloc::borrow::*;
 }
+
+pub mod thread {
+	/// Returns if the current thread is panicking.
+	///
+	/// In wasm this always returns `false`, as we abort on any panic.
+	pub fn panicking() -> bool {
+		false
+	}
+}