[MEL] - Implement L2 messages accumulation and introduce MessageReader to extract messages from preimages #4258

ganeshvanahalli · 2026-01-16T11:28:27Z

This PR implements accumulating of L2 messages in every mel state by introducing two new fields-

MsgRoot                 => Merkle root of the Merkle tree of all the messages extracted by MEL
MessageMerklePartials   => Merkle partials of the Merkle tree of all the messages extracted by MEL

We also introduce MessageReader struct in melreplay package that will be use by the unified replay binary to read L2 messages from preimages

Resolves NIT-3522

…ages

…ract messages from preimages

codecov · 2026-01-16T11:50:30Z

Codecov Report

❌ Patch coverage is 0% with 172 lines in your changes missing coverage. Please review.
✅ Project coverage is 29.27%. Comparing base (3a25bb0) to head (16a60d7).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4258      +/-   ##
==========================================
- Coverage   32.94%   29.27%   -3.67%     
==========================================
  Files         471      474       +3     
  Lines       56610    56688      +78     
==========================================
- Hits        18648    16597    -2051     
- Misses      34713    37094    +2381     
+ Partials     3249     2997     -252

github-actions · 2026-01-16T12:30:51Z

❌ 3 Tests Failed:

Tests completed	Failed	Passed	Skipped
3923	3	3920	0

View the top 3 failed tests by shortest run time

TestBroadcasterSendsCachedMessagesOnClientConnect

Stack Traces | -0.000s run time

... [CONTENT TRUNCATED: Keeping last 20 lines]
INFO [01-26|07:20:27.852] Feed connected                           feedServerVersion=2 chainId=8744 requestedSeqNum=2
    broadcastclient_test.go:774: client 1 received second message: {1 {0xc0002fee40 0} &lt;nil&gt; [101 51 64 132 204 151 247 186 138 50 43 21 37 47 175 242 79 134 24 70 178 249 251 99 226 214 98 192 127 139 86 58 107 208 234 45 106 154 249 145 95 135 199 6 93 66 175 139 115 243 86 179 75 244 24 64 152 101 101 60 166 238 42 2 0] [] 0}
    broadcastclient_test.go:774: client 0 received second message: {0 {0xc000494f00 0} &lt;nil&gt; [123 212 6 160 96 224 70 26 69 55 124 254 121 111 215 8 253 37 134 113 232 63 10 66 113 114 55 197 91 54 129 133 99 58 42 105 49 94 205 86 195 159 147 184 221 188 173 69 252 254 235 123 224 74 20 55 48 147 135 90 24 89 117 173 0] [] 0}
ERROR[01-26|07:20:28.042] Server connection timed out without receiving data url=ws://127.0.0.1:40577/ err="read tcp4 127.0.0.1:53478-&gt;127.0.0.1:40577: i/o timeout"
INFO [01-26|07:20:28.043] First reconnection attempt, skipping backoff url=ws://127.0.0.1:40577/
INFO [01-26|07:20:28.043] connecting to arbitrum inbox message broadcaster url=ws://127.0.0.1:40577/
INFO [01-26|07:20:28.043] Feed connected                           feedServerVersion=2 chainId=8742 requestedSeqNum=0
ERROR[01-26|07:20:28.054] Server connection timed out without receiving data url=ws://127.0.0.1:35077/ err="read tcp4 127.0.0.1:47890-&gt;127.0.0.1:35077: i/o timeout"
INFO [01-26|07:20:28.054] First reconnection attempt, skipping backoff url=ws://127.0.0.1:35077/
INFO [01-26|07:20:28.054] connecting to arbitrum inbox message broadcaster url=ws://127.0.0.1:35077/
ERROR[01-26|07:20:28.244] Server connection timed out without receiving data url=ws://127.0.0.1:40577/ err="read tcp4 127.0.0.1:53492-&gt;127.0.0.1:40577: i/o timeout"
INFO [01-26|07:20:28.244] First reconnection attempt, skipping backoff url=ws://127.0.0.1:40577/
INFO [01-26|07:20:28.244] connecting to arbitrum inbox message broadcaster url=ws://127.0.0.1:40577/
INFO [01-26|07:20:28.244] Feed connected                           feedServerVersion=2 chainId=8742 requestedSeqNum=0
ERROR[01-26|07:20:28.445] Server connection timed out without receiving data url=ws://127.0.0.1:40577/ err="read tcp4 127.0.0.1:53504-&gt;127.0.0.1:40577: i/o timeout"
INFO [01-26|07:20:28.445] First reconnection attempt, skipping backoff url=ws://127.0.0.1:40577/
INFO [01-26|07:20:28.445] connecting to arbitrum inbox message broadcaster url=ws://127.0.0.1:40577/
INFO [01-26|07:20:28.446] Feed connected                           feedServerVersion=2 chainId=8742 requestedSeqNum=0
ERROR[01-26|07:20:28.646] Server connection timed out without receiving data url=ws://127.0.0.1:40577/ err="read tcp4 127.0.0.1:53518-&gt;127.0.0.1:40577: i/o timeout"
INFO [01-26|07:20:28.646] First reconnection attempt, skipping backoff url=ws://127.0.0.1:40577/

TestSequencerPriceAdjustsFrom25Gwei

Stack Traces | 22.510s run time

... [CONTENT TRUNCATED: Keeping last 20 lines]
INFO [01-26|07:33:17.850] Chain head was updated                   number=5   hash=2f8b29..72d947 root=407e53..9abc9b elapsed="362.109µs"
INFO [01-26|07:33:17.856] Submitted contract creation              hash=0x0ddfe5250b1b74d92f95db89f81466643b74ce02f040d082ecf1f09229d6a325 from=0x57Ff0F473737a1c161bfF9efDF016F7991585088 nonce=21   contract=0x5E6d7135B0a5F12bF935A83B7d5b5e4a8BFf112d value=0
INFO [01-26|07:33:17.858] Starting work on payload                 id=0x03fa9b6824971708
INFO [01-26|07:33:17.859] Updated payload                          id=0x03fa9b6824971708 number=25  hash=429507..d6609a txs=1   withdrawals=0 gas=3,088,290  fees=3.08829e-06    root=aed14d..b71044 elapsed="849.643µs"
INFO [01-26|07:33:17.859] Stopping work on payload                 id=0x03fa9b6824971708 reason=delivery
INFO [01-26|07:33:17.860] Imported new potential chain segment     number=25  hash=429507..d6609a blocks=1  txs=1   mgas=3.088  elapsed=1.216ms      mgasps=2538.370 triediffs=90.14KiB   triedirty=0.00B
INFO [01-26|07:33:17.861] Chain head was updated                   number=25  hash=429507..d6609a root=aed14d..b71044 elapsed="307.537µs"
INFO [01-26|07:33:17.878] Submitted transaction                    hash=0x4262da1cdd0bc434676ac17ecc89cceaef3910c0fa62d976aa817ed2a4d2e3a7 from=0x26E554a8acF9003b83495c7f45F06edCB803d4e3 nonce=42   recipient=0x0C709F340F0BB2e361229e345B7e26999d0969Ab value=340,282,366,920,938,463,463,374,607,431,768,211,456
INFO [01-26|07:33:17.893] InboxTracker                             sequencerBatchCount=5   messageCount=6    l1Block=35  l1Timestamp=2026-01-26T07:33:17+0000
INFO [01-26|07:33:17.898] Submitted transaction                    hash=0xb5e8d40fc12fe980a55e08550a6941df75812577755c3e64a001463668926452 from=0x26E554a8acF9003b83495c7f45F06edCB803d4e3 nonce=6    recipient=0x0000000000000000000000000000000000000071 value=1,000,000,000,000,000,000
�[90mTime to activate hostio-test: 249.272133ms�[0;0m
INFO [01-26|07:33:17.902] InboxTracker                             sequencerBatchCount=17  messageCount=41   l1Block=46  l1Timestamp=2026-01-26T07:33:17+0000
INFO [01-26|07:33:17.904] Submitted transaction                    hash=0xcda12a443567eb36c98bf156618367cc7a1c464c9b8e915f5a4914fbc9db3bae from=0xb386a74Dcab67b66F8AC07B4f08365d37495Dd23 nonce=4    recipient=0xD0df7e8CfAc6dD6444d8c91FcBB7a87C15B776ea value=0
INFO [01-26|07:33:17.904] DataPoster sent transaction              nonce=4    hash=cda12a..db3bae feeCap=17,187,573,830 tipCap=50,000,000    blobFeeCap=&lt;nil&gt; gas=721,339
INFO [01-26|07:33:17.904] BatchPoster: batch sent                  sequenceNumber=5   from=6    to=7    prevDelayed=1   currentDelayed=1   totalSegments=3  numBlobs=0
INFO [01-26|07:33:17.905] Starting work on payload                 id=0x0325cbb9096dc530
INFO [01-26|07:33:17.906] Submitted contract creation              hash=0xd8bc7246b6bfae04fa810bb28f6dcfdda1dff054b6a5eb383b20a9901e8336c6 from=0x26E554a8acF9003b83495c7f45F06edCB803d4e3 nonce=7    contract=0x52AefB40754517B3A0A1672b01DC2930a7851444 value=0
INFO [01-26|07:33:17.907] Updated payload                          id=0x0325cbb9096dc530 number=36  hash=5885f2..7d14d9 txs=1   withdrawals=0 gas=704,580    fees=3.5229e-05     root=8a8d25..b8d4d4 elapsed=1.223ms
INFO [01-26|07:33:17.907] Stopping work on payload                 id=0x0325cbb9096dc530 reason=delivery
INFO [01-26|07:33:17.909] Imported new potential chain segment     number=36  hash=5885f2..7d14d9 blocks=1  txs=1   mgas=0.705  elapsed=1.700ms      mgasps=414.267  triediffs=184.50KiB  triedirty=0.00B

TestFastConfirmationWithSafe

Stack Traces | 48.320s run time

... [CONTENT TRUNCATED: Keeping last 20 lines]
INFO [01-26|07:33:40.419] Stopping work on payload                 id=0x037ce7d98fc9927d reason=delivery
INFO [01-26|07:33:40.420] Imported new potential chain segment     number=334 hash=6512bf..9551fe blocks=1  txs=1   mgas=0.021 elapsed=1.502ms     mgasps=13.977   triediffs=679.21KiB triedirty=150.03KiB
INFO [01-26|07:33:40.421] Chain head was updated                   number=334 hash=6512bf..9551fe root=953c44..824727 elapsed="113.48µs"
INFO [01-26|07:33:40.421] Persisted dirty state to disk            size=651.15KiB elapsed=17.382ms
INFO [01-26|07:33:40.421] Starting work on payload                 id=0x03397ff1ee69e7bf
INFO [01-26|07:33:40.422] Blockchain stopped
INFO [01-26|07:33:40.421] Updated payload                          id=0x03065d405ae0a299 number=71  hash=29ee5b..9acdff txs=1   withdrawals=0 gas=21000     fees=0.002099709926 root=029122..ae7bc4 elapsed=1.726ms
INFO [01-26|07:33:40.422] Stopping work on payload                 id=0x03065d405ae0a299 reason=delivery
INFO [01-26|07:33:40.423] Updated payload                          id=0x03397ff1ee69e7bf number=388 hash=c02e55..523290 txs=1   withdrawals=0 gas=21000     fees=0.0021         root=480ffb..e6bc0e elapsed=1.281ms
INFO [01-26|07:33:40.423] Imported new potential chain segment     number=71  hash=29ee5b..9acdff blocks=1  txs=1   mgas=0.021 elapsed=1.309ms     mgasps=16.033   triediffs=317.63KiB triedirty=0.00B
INFO [01-26|07:33:40.423] Chain head was updated                   number=71  hash=29ee5b..9acdff root=029122..ae7bc4 elapsed="76.472µs"
INFO [01-26|07:33:40.424] New Key                                  name=Faucet              Address=0xaF24Ca6c2831f4d4F629418b50C227DF0885613A
INFO [01-26|07:33:40.424] Stopping work on payload                 id=0x03397ff1ee69e7bf reason=delivery
INFO [01-26|07:33:40.424] New Key                                  name=RollupOwner         Address=0x57Ff0F473737a1c161bfF9efDF016F7991585088
--- FAIL: TestFastConfirmationWithSafe (48.32s)
INFO [01-26|07:33:40.424] New Key                                  name=Sequencer           Address=0xb386a74Dcab67b66F8AC07B4f08365d37495Dd23
INFO [01-26|07:33:40.424] New Key                                  name=Validator           Address=0x83FFCFaCE2Fb0E1286686815503608A16EF41e47
INFO [01-26|07:33:40.424] New Key                                  name=User                Address=0x7E23C8862920797d81916d62c274dd9217113e28
INFO [01-26|07:33:40.425] Allocated trie memory caches             clean=154.00MiB dirty=256.00MiB
INFO [01-26|07:33:40.425] State schema set to default              scheme=path

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…tion

rauljordan

This looks really good to me so far, no need to keep in draft IMO

The base branch was changed.

…yedInboxMessage

Realized that some issues will happen with the current code because we changed delayed msg hashes

rauljordan · 2026-01-22T15:03:47Z

arbnode/mel/messages.go

-		crypto.Keccak256(m.Message.L2msg),
-	)
-	return crypto.Keccak256Hash(hash)
+	encoded, err := rlp.EncodeToBytes(m.WithMELRelevantFields())


@ganeshvanahalli won't this break existing code? We want to eventually merge to master and cannot break existing logic

Hash() method is only used by MEL code currently, the rest of the codebase (tracker, reader etc..) uses AfterInboxAcc method

rauljordan and others added 24 commits January 5, 2026 22:09

begin tx recorder for mel

5aa9a51

fix recorder

4065abc

add unit test for tx recorder

3cbd6a4

fix tx recorder

337bf3c

add changelog and fix lint

6f38c63

Implement receipt recorder for mel validation

790e83f

code refactor

014f267

refactor

d7aa9fc

Make tx and receipt fetcher in mel-replay to work with recorded preim…

59b75ca

…ages

remove debug statement

ccf0e22

code refactor

439c59d

update impl of GetPreimages

36e255f

reduce code diff

472150c

fix test

ddbd9f4

address PR comments

a015068

resolve conflicts

1658afe

code refactor

97b40d0

Merge branch 'mel-txandreceipt-recorder' into mel-txandreceipt-fetcher

afa84e1

address PR comments

95646c2

move mel replay code to its own package

d562843

implement typeBasedPreimageResolver

09c3fb4

Merge branch 'master' into mel-txandreceipt-recorder

de68c31

Merge branch 'mel-txandreceipt-recorder' into mel-txandreceipt-fetcher

5073fdc

Implement L2 messages accumulation and introduce MessageReader to ext…

7cf3fdd

…ract messages from preimages

ganeshvanahalli requested a review from rauljordan January 16, 2026 11:28

ganeshvanahalli assigned rauljordan Jan 16, 2026

add changelog

284104c

fix typos

5456ce3

ganeshvanahalli and others added 3 commits January 20, 2026 17:06

Merge branch 'mel-txandreceipt-fetcher' into implement-l2msg-accumula…

85b3e26

…tion

delete irrelevant test files

d6a5fae

Merge branch 'mel-txandreceipt-fetcher' into implement-l2msg-accumula…

b291653

…tion

ganeshvanahalli marked this pull request as draft January 20, 2026 17:31

rauljordan previously approved these changes Jan 20, 2026

View reviewed changes

rauljordan assigned ganeshvanahalli and unassigned rauljordan Jan 20, 2026

Base automatically changed from mel-txandreceipt-fetcher to master January 21, 2026 03:51

ganeshvanahalli and others added 2 commits January 21, 2026 10:22

Merge branch 'master' into implement-l2msg-accumulation

70c9b20

do not include batchPostingReport related fields in Hash impl of Dela…

b7f136a

…yedInboxMessage

ganeshvanahalli marked this pull request as ready for review January 21, 2026 09:31

ganeshvanahalli requested a review from rauljordan January 21, 2026 09:31

ganeshvanahalli assigned rauljordan and unassigned ganeshvanahalli Jan 21, 2026

ganeshvanahalli and others added 3 commits January 21, 2026 15:54

minor fix

46fa37c

Merge branch 'master' into implement-l2msg-accumulation

3bb112e

bug fixes

8b1cabf

rauljordan previously approved these changes Jan 22, 2026

View reviewed changes

rauljordan assigned eljobe and unassigned rauljordan Jan 22, 2026

rauljordan assigned ganeshvanahalli and unassigned eljobe Jan 22, 2026

rauljordan reviewed Jan 22, 2026

View reviewed changes

ganeshvanahalli requested a review from rauljordan January 22, 2026 15:44

ganeshvanahalli assigned rauljordan and unassigned ganeshvanahalli Jan 23, 2026

Merge branch 'master' into implement-l2msg-accumulation

16a60d7

tsahee marked this pull request as draft January 28, 2026 16:29

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[MEL] - Implement L2 messages accumulation and introduce MessageReader to extract messages from preimages #4258

[MEL] - Implement L2 messages accumulation and introduce MessageReader to extract messages from preimages #4258

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[MEL] - Implement L2 messages accumulation and introduce MessageReader to extract messages from preimages #4258

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[MEL] - Implement L2 messages accumulation and introduce MessageReader to extract messages from preimages #4258

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