sae: Implement custom tx `AsOp` by StephenButtolph · Pull Request #5308 · ava-labs/avalanchego

StephenButtolph · 2026-04-26T14:51:13Z

Why this should be merged

This PR factors out Tx.AsOp from #5303.

How this works

Tx.AsOp includes multiple pieces of critical data for SAE:

op.Gas - which correlates to atomic.UnsignedTx.GasUsed in coreth.
op.GasFeeCap - which correlates to atomic.EffectiveGasPrice in coreth.
op.Burn and op.Mint - which correlate to the non-multicoin modifications in atomic.UnsignedTx.EVMStateTransfer in coreth.

How this was tested

Extended existing mainnet tx tests to include ops
Extended tx tests to include additional mainnet tx
Extended tx tests to include synthetic txs for edge cases
Added TestAsOp_Errors to test error conditions
Fuzzed AsOp against coreth

Need to be documented in RELEASES.md?

No

…ttolph/atomic-tx-rewrite.2

alarso16 · 2026-04-30T17:56:29Z

+
+// scaleAVAX converts an amount denominated in nAVAX into the C-Chain's aAVAX
+// denomination.
+func scaleAVAX(nAVAX uint64) uint256.Int {


IMO this name should be clear that this is a one way conversion from X-chain to C-chain. I don't have a better name for this, but reading the code doesn't not make it clear the denominations we end up with

I suppose I was relying on the types to make it clear that the AVAX was being scaled upwards rather than downwards. xAVAXToC feels like a horrible name... toAAVAX also seems gross... bigAVAX could work, although I'm not sure that really addresses your concern

Not a big enough deal to block merge, and those options are worse... I guess we can keep it

alarso16 · 2026-04-30T18:00:51Z

+	// Imported for [atomic.TxBytesGas] comment resolution.
+	_ "github.com/ava-labs/avalanchego/graft/coreth/plugin/evm/atomic"


I don't think you should import this just for the comment resolution. You could write out the path

Hm, why not? Is the concern about init functions in coreth? I don't think there is anything too concerning in the init functions.. I suppose maybe the concern is around the ext data hashes?

meh whatever, i just thought it was unnecessary. but we can punt this until we eventually deprecate coreth completely

I think we've been fine adding imports for comment resolution previously.

Copilot

Pull request overview

This PR adds an SAE-focused conversion path from C-Chain atomic transactions into hook.Op by implementing Tx.AsOp, including gas used, effective gas price, and AVAX mint/burn effects that correspond to coreth’s atomic tx accounting.

Changes:

Add Tx.AsOp(avaxAssetID) plus supporting gas/fee and AVAX-scaling helpers.
Extend Import/Export to implement new Unsigned interface methods (burned, numSigs, asOp) to generate SAE operations.
Expand unit tests and add a fuzz compatibility test to compare AsOp behavior against coreth.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
`vms/saevm/cchain/tx/tx.go`	Introduces `Tx.AsOp` and supporting gas/fee calculation helpers.
`vms/saevm/cchain/tx/import.go`	Implements `Unsigned` methods for imports and generates mint-side `hook.Op` data.
`vms/saevm/cchain/tx/export.go`	Implements `Unsigned` methods for exports and generates burn-side `hook.Op` data.
`vms/saevm/cchain/tx/tx_test.go`	Extends mainnet + synthetic vectors and adds `AsOp` unit/error tests.
`vms/saevm/cchain/tx/compatibility_test.go`	Adds fuzzing to compare `AsOp` output vs coreth state transfer.
`vms/saevm/cchain/tx/BUILD.bazel`	Updates Bazel deps for new imports (uint256, hook, gas/math, ap5).

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JonathanOppenheimer

need to go through tests more

JonathanOppenheimer · 2026-04-30T22:41:54Z

+	// Imported for [atomic.TxBytesGas] comment resolution.
+	_ "github.com/ava-labs/avalanchego/graft/coreth/plugin/evm/atomic"


I think we've been fine adding imports for comment resolution previously.

JonathanOppenheimer · 2026-05-01T20:39:25Z

-			ID:    ids.FromStringOrPanic("h34BPNmYApCbW8buVWAtzu1KtjTFmyMhiRQQnAqPqwCqQsB7f"),
 			Bytes: common.FromHex("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"),
+			Op: hook.Op{
+				ID:  ids.FromStringOrPanic("h34BPNmYApCbW8buVWAtzu1KtjTFmyMhiRQQnAqPqwCqQsB7f"),


What's the value in hard-coding these per test? Does this catch regressions?

Could we instead hash test.Bytes on the fly,to get the ID with some kind of helper for all of these instances -- I feel like that would be simpler than the current setup.

I feel like hashing the bytes is just duplicating the code in the test

StephenButtolph added 16 commits April 25, 2026 18:42

sae: Add C-chain custom tx serialization

eb8c0a0

sae: Implement AsOp

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wip

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comments

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reduce exported identifiers

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wip

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wip

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wip

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Extend fuzz tests

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nit

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wip

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wip

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wip

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wip

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nit

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nit

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github-project-automation Bot added this to avalanchego Apr 26, 2026

StephenButtolph and others added 13 commits April 26, 2026 14:13

lint

f2faffb

lint

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nits

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fix bazel

0369966

ci: free runner disk before publishing Antithesis images (#5310)

85ae854

Merge branch 'master' into StephenButtolph/atomic-tx-rewrite.1

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Merge branch 'master' into StephenButtolph/atomic-tx-rewrite.1

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Merge branch 'master' into StephenButtolph/atomic-tx-rewrite.1

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merged

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nit

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fuzz full op

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mark as compatibility

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nit

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StephenButtolph added 3 commits April 30, 2026 12:39

Merge branch 'StephenButtolph/smart-atomic-tx-fuzzing' into StephenBu…

61dcfbd

…ttolph/atomic-tx-rewrite.2

merged

ca7c26b

Merge branch 'StephenButtolph/smart-atomic-tx-fuzzing' into StephenBu…

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…ttolph/atomic-tx-rewrite.2

alarso16 reviewed Apr 30, 2026

View reviewed changes

StephenButtolph added 7 commits April 30, 2026 14:46

cleanup

40c3ba6

cleanup

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Add more cases

f0515ec

add comments

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Add interface check

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nit

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grammar

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alarso16 approved these changes Apr 30, 2026

View reviewed changes

more succinct

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Base automatically changed from StephenButtolph/smart-atomic-tx-fuzzing to master April 30, 2026 22:08

StephenButtolph added 2 commits April 30, 2026 18:24

merged

cfd18da

pedantic

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Copilot AI review requested due to automatic review settings April 30, 2026 22:42

Copilot started reviewing on behalf of StephenButtolph April 30, 2026 22:43 View session

Copilot AI reviewed Apr 30, 2026

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Comment thread vms/saevm/cchain/tx/compatibility_test.go

JonathanOppenheimer reviewed Apr 30, 2026

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StephenButtolph added 2 commits April 30, 2026 19:43

ok

eb701ee

Document codec weirdness

1ad0654

JonathanOppenheimer approved these changes May 1, 2026

View reviewed changes

StephenButtolph added 2 commits May 2, 2026 11:21

simplify

ac82445

Merge branch 'master' into StephenButtolph/atomic-tx-rewrite.2

cab3300

StephenButtolph added this pull request to the merge queue May 2, 2026

Merged via the queue into master with commit c8a1e07 May 2, 2026
60 checks passed

StephenButtolph deleted the StephenButtolph/atomic-tx-rewrite.2 branch May 2, 2026 16:05

github-project-automation Bot moved this from In Progress 🏗️ to Done 🎉 in avalanchego May 2, 2026

		// Imported for [atomic.TxBytesGas] comment resolution.
		_ "github.com/ava-labs/avalanchego/graft/coreth/plugin/evm/atomic"

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StephenButtolph commented Apr 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Why this should be merged

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Need to be documented in RELEASES.md?

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StephenButtolph commented Apr 26, 2026 •

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