Gloas alpha spec 8 by eserilev · Pull Request #9315 · sigp/lighthouse

eserilev · 2026-05-18T12:20:14Z

Issue Addressed

https://github.com/ethereum/consensus-specs/releases/tag/v1.7.0-alpha.8

mergify · 2026-05-18T16:38:59Z

Some required checks have failed. Could you please take a look @eserilev? 🙏

…atch the spec and pass ef test

pawanjay176 · 2026-05-20T00:32:37Z


-    if proposal_epoch < current_epoch || proposal_epoch > current_epoch.saturating_add(1u64) {
+    if proposal_epoch < current_epoch
+        || proposal_epoch > current_epoch.saturating_add(spec.min_seed_lookahead)


ethereum/consensus-specs#5215 also says that

is_valid_proposal_slot(state, preferences) returns True, where
state is the checkpoint state at the epoch compute_epoch_at_slot(preferences.proposal_slot) - MIN_SEED_LOOKAHEAD and
the root preferences.dependent_root.

We use the head_state here which seems correct and given our previous discussion on not wanting to accept all preferences that force us to load old states. I think that is fine. Do you think this changes?

We also need to update BeaconState::is_valid_proposal_slot to use min_seed_lookahead right?

The PR also changes it in get_upcoming_proposal_slots but I don't see any direct usage of it in our codebase. This spec change is so annoying.

pawanjay176

I have reviewed the non fork choice changes and they look good. Mostly nits

pawanjay176 · 2026-05-20T18:21:21Z

+        execution_layer
+            .get_proposer_gas_limit(proposer_index)
+            .await
+            .unwrap_or(parent_gas_limit),


Shouldn't this be the default that we have configured in lighthouse instead of the parent gas limit?

Yeah agree, I think there's no harm in setting a higher gas limit here, because this is just the target. It also solves the problem I found which is that this isn't actually the parent_gas_limit anyway:

#9315 (comment)

pawanjay176 · 2026-05-20T19:05:28Z

+                        "No proposer gas limit configured, falling back to parent gas limit"
+                    );
+                }
+                proposer_gas_limit.or(Some(pre_payload_attributes.parent_gas_limit))


I couldn't find the relevant part of the spec where we fall back to the parent gas limit instead of the configured default in lighthouse

michaelsproul

Looks good. I think maybe we just add a TODO for the parent gas limit issue I raised, seeing as it is only used as a fallback, and even then is only used as a target gas limit (it can't break anything I don't think).

michaelsproul · 2026-05-21T01:27:49Z

+            cached_head
+                .snapshot
+                .beacon_state
+                .latest_execution_payload_bid()?
+                .gas_limit


I think this is wrong in the case where we build on the Full variant of the parent. The payload has not yet been applied to state in this case, so its gas limit won't be stored in state.latest_execution_payload_bid.

I think we would need to thread the proposer_head_payload_status through here, or maybe just the proposer head payload envelope, and then load the gas limit from that envelope.

michaelsproul · 2026-05-21T02:06:59Z

Actually, Pawan's suggestion is even cleaner. Get rid of parent_gas_limit from PrePayloadAttributes entirely and just use the process-level default gas limit as fallback.

pawanjay176

LGTM.

pawanjay176 · 2026-05-21T17:56:40Z

    let payload_parameters = PayloadParameters {
        parent_hash: parent_block_hash,
-        parent_gas_limit,
+        parent_gas_limit: target_gas_limit.unwrap_or(DEFAULT_GAS_LIMIT),


Wait sorry I don't think this is right. The parent_gas_limit just reports the gas limit of whatever we are building on right?

yeah my bad, I thought we didn't need an accurate parent gas limit but maybe we do?

Actually I think this is basically unrelated to Gloas. AFAICT the parent_gas_limit in PayloadParameters is only used in verify_builder_bid, which isn't active post-Gloas.

Still, we could safely (and correctly) initialise here by using the parent payload envelope, which is available earlier in the call stack.

We can also fully delete parent_gas_limit from PrePayloadAttributes I think

Ohh that makes sense. I was wondering why we are passing it in the payload attributes when the EL already knows about the parent gas limit.

Applied my idea in:

124f0c4

pawanjay176

Latest fix looks good. Lets merge 🚀

mergify · 2026-05-22T01:09:43Z

Merge Queue Status

✅ Entered queue — 2026-05-22 01:09 UTC · Rule: default
✅ Checks started · on draft merge queue: embarking unstable (b5d5644) and #9315 together #9334
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🚫 Left the queue — 2026-05-22 01:32 UTC · at 124f0c48b888b099bb410579282f9349cec4f1bb

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michaelsproul · 2026-05-22T05:52:00Z

@mergify requeue

mergify · 2026-05-22T05:52:11Z

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✅ Entered queue — 2026-05-22 05:52 UTC · Rule: default
✅ Checks passed · on draft merge queue: embarking unstable (b5d5644) and #9315 together #9335
✅ Merged — 2026-05-22 06:21 UTC · at 124f0c48b888b099bb410579282f9349cec4f1bb · squash

This pull request spent 29 minutes 14 seconds in the queue, including 27 minutes 33 seconds running CI.

Required conditions to merge

#approved-reviews-by >= 1 [🛡 GitHub branch protection]
- Gloas alpha spec 8 #9315
#changes-requested-reviews-by = 0 [🛡 GitHub branch protection]
- Gloas alpha spec 8 #9315
check-success=local-testnet-success
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eserilev added 11 commits May 18, 2026 10:24

Proposer preferences uses checkpoint root

3fe2448

Use min seed lookahead for proposer preferences verification

828b9c6

Add payload_due_bps and relevant check

08be7f5

count ptc votes from duplicated validators

93bcd6c

MIN_BUILDER_WITHDRAWABILITY_DELAY update mainnet values

b3ac2ff

track ptc participation

bb23439

allow proposer to re-org unavail blocks

d2f26d3

add target gas limit to paylaod attributes

45905dc

check bid gas limit consistency w/ target

53817f7

fmt

d92b95a

cleanup

d800535

eserilev requested a review from jxs as a code owner May 18, 2026 12:20

eserilev added the gloas label May 18, 2026

eserilev added 7 commits May 18, 2026 15:34

add unit tests for is_gas_limit_target_compatible

6a2dc05

builder deposit optimization

c9a60b1

FMT

49e83c3

Revert changes to ProposerPreferences

3878543

Fix tests

a693d56

Allow type com[plexity

f578674

update TODO

e7eb8cd

eserilev added the ready-for-review The code is ready for review label May 18, 2026

mergify Bot added waiting-on-author The reviewer has suggested changes and awaits thier implementation. and removed ready-for-review The code is ready for review labels May 18, 2026

eserilev added 6 commits May 18, 2026 21:53

Cleanup

bc98ad1

Fix fork choice issue

98ed9b9

fix

bcea7c9

Update

8926f61

Revert some more changes

e82ef46

Another revert

8d4f378

check payload_received in should_extend_payload

e690423

eserilev requested a review from pawanjay176 May 20, 2026 14:41

eserilev added 2 commits May 20, 2026 19:20

move payload attestation current check to on_payload_attestation to m…

fce5898

…atch the spec and pass ef test

lint

cb2c113

pawanjay176 reviewed May 20, 2026

View reviewed changes

michaelsproul approved these changes May 21, 2026

View reviewed changes

eserilev added 2 commits May 21, 2026 15:10

add process wide fallback

2752356

Use min seed lokahead fix

800d05a

pawanjay176 approved these changes May 21, 2026

View reviewed changes

pawanjay176 reviewed May 21, 2026

View reviewed changes

Clean up parent_gas_limit

124f0c4

pawanjay176 approved these changes May 22, 2026

View reviewed changes

pawanjay176 added ready-for-merge This PR is ready to merge. and removed waiting-on-author The reviewer has suggested changes and awaits thier implementation. labels May 22, 2026

mergify Bot added the queued label May 22, 2026

mergify Bot added a commit that referenced this pull request May 22, 2026

Merge of #9315

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mergify Bot mentioned this pull request May 22, 2026

merge queue: embarking unstable (b5d5644) and #9315 together #9334

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Merge of #9315

dfb37ba

mergify Bot mentioned this pull request May 22, 2026

merge queue: embarking unstable (b5d5644) and #9315 together #9335

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mergify Bot merged commit 60abd4b into sigp:unstable May 22, 2026
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eserilev commented May 18, 2026

Issue Addressed

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