From 1bc2f51f3704369e5205ce4bf00047c811d66383 Mon Sep 17 00:00:00 2001
From: David Himmelstrup <david.himmelstrup@chainsafe.io>
Date: Wed, 2 Oct 2024 10:43:46 +0200
Subject: [PATCH] fix: return null in `MinerGetBaseInfo` if miner hasn't been
 around for 900 epochs (#4820)

---
 CHANGELOG.md             | 2 ++
 src/state_manager/mod.rs | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index da3b10f39246..de5f06aebb86 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -49,6 +49,8 @@
 
 - [#4809](https://github.com/ChainSafe/forest/issues/4777) the Mac OS X build on
   Apple silicons works
+- [#4820](https://github.com/ChainSafe/forest/pull/4820) Fix edge-case in
+  `Filecoin.MinerGetBaseInfo` RPC method.
 
 ## Forest 0.20.0 "Brexit"
 
diff --git a/src/state_manager/mod.rs b/src/state_manager/mod.rs
index 9179cdfa5f0c..cf50250b8118 100644
--- a/src/state_manager/mod.rs
+++ b/src/state_manager/mod.rs
@@ -1214,7 +1214,14 @@ where
             epoch,
         )?;
 
+        // If the miner actor doesn't exist in the current tipset, it is a
+        // user-error and we must return an error message. If the miner exists
+        // in the current tipset but not in the lookback tipset, we may not
+        // error and should instead return None.
         let actor = self.get_required_actor(&addr, *tipset.parent_state())?;
+        if self.get_actor(&addr, lb_state_root)?.is_none() {
+            return Ok(None);
+        }
 
         let miner_state = miner::State::load(self.blockstore(), actor.code, actor.state)?;