forge coverage ignores empty receive() function

[krakovia-evm]

Component

Forge

Have you ensured that all of these are up to date?

• [X] Foundry
• [ ] Foundryup

What version of Foundry are you on?

forge 0.2.0 (7a23a5c 2024-12-01T00:29:03.740254700Z)

What command(s) is the bug in?

forge coverage

Operating System

Windows

Describe the bug

"forge coverage" seems to ignore receive() functions if their body is empty in tests. Simple poc

1. forge init —no-git
2. add receive() external payable {} to Counter.sol
3. add this test to Counter.t.sol

   function test_receive() public {
       (bool success,) = address(counter).call{value: 1 ether}("");
       assertTrue(success);
   }

4. run forge coverage / forge coverage —report lcov

we should get 100% coverage, instead the receive function is red (but we touch it in the tests)

[14675] CounterTest::test_receive()
    ├─ [55] Counter::receive{value: 1000000000000000000}()
    │   └─ ← [Stop]
    ├─ [0] VM::assertTrue(true) [staticcall]
    │   └─ ← [Return]
    └─ ← [Stop]

If i add an emit inside the receive() function it gets correctly (green) flagged.

[DaniPopes]

cc @grandizzy the easiest fix would be to skip adding fallback/receive if the body is empty as well but I don't know if this is right

[grandizzy]

cc @grandizzy the easiest fix would be to skip adding fallback/receive if the body is empty as well but I don't know if this is right

That makes sense, I overlooked empty body when enabled support for receive in https://github.com/foundry-rs/foundry/pull/9288

[DaniPopes]

I am asking because we can register hits for empty functions but not receive/fallback, I would like to fix the underlying issue

[grandizzy]

ah, I see, I had the impression we already register hits for empty functions so my suggestion was to ignore empty receive/fallback only