Reviewing files that changed from the base of the PR and between 154bf9c and 19eda8e.

• CHANGELOG.md (1 hunks)
• src/chain_sync/bad_block_cache.rs (1 hunks)
• src/chain_sync/chain_follower.rs (4 hunks)
• src/chain_sync/tipset_syncer.rs (3 hunks)

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src/chain_sync/tipset_syncer.rs (1)

105-106: Don’t mark transient validation errors as permanently bad (exclude TipsetParentNotFound).

Current logic excludes only TimeTravellingBlock; TipsetParentNotFound is also transient (see Lines 196–205), but will be pushed to bad_block_cache, causing permanent rejection. Align with Lotus’ isPermanent(err) idea.

Apply within validate_tipset:

-                warn!("Validating block [CID = {cid}] in EPOCH = {epoch} failed: {why}");
-                match &why {
-                    TipsetSyncerError::TimeTravellingBlock(_, _) => {
-                        // Do not mark a block as bad for temporary errors.
-                        // See <https://github.com/filecoin-project/lotus/blob/v1.34.1/chain/sync.go#L602> in Lotus
-                    }
-                    _ => {
-                        if let Some(bad_block_cache) = bad_block_cache {
-                            bad_block_cache.push(cid);
-                        }
-                    }
-                };
+                warn!(epoch, %cid, error = %why, "block validation failed");
+                let is_temp = matches!(
+                    &why,
+                    TipsetSyncerError::TimeTravellingBlock(_, _)
+                        | TipsetSyncerError::TipsetParentNotFound(_)
+                );
+                if !is_temp {
+                    if let Some(ref bad_block_cache) = bad_block_cache {
+                        bad_block_cache.push(cid);
+                    }
+                }

Optionally extract the predicate:

fn is_temporary_sync_error(e: &TipsetSyncerError) -> bool {
    matches!(e,
        TipsetSyncerError::TimeTravellingBlock(_, _)
        | TipsetSyncerError::TipsetParentNotFound(_)
    )
}

Then use if !is_temporary_sync_error(&why) { … }.

Also applies to: 129-140

⛔ Skipped due to learnings

Learnt from: hanabi1224
Repo: ChainSafe/forest PR: 5886
File: src/daemon/db_util.rs:236-259
Timestamp: 2025-08-11T14:00:47.060Z
Learning: In Forest's snapshot import (`src/daemon/db_util.rs`), when F3 CID is present in snapshot metadata but the actual F3 data is missing, this should cause a hard error as it indicates snapshot corruption. Only errors during the F3 import process itself (after data is successfully retrieved) should be non-fatal and logged.

src/chain_sync/chain_follower.rs (1)

233-234: Ripgrep found the validate_tipset call site as expected, but cargo check failed due to environment limitations.

The rg search located the call to validate_tipset at line 851, which falls within the changed range (852–859). However, the sandbox environment lacks a C compiler, preventing cargo check from completing. The structural changes appear correct, but manual verification in your local environment is required to confirm compilation:

cargo check -q

Also applies to: 260-261, 829-835, 852-859