feat(AggLayer bridge-out e2e #2): store Local Exit Tree in `AggLayerBridge` contract and update it upon `B2AGG` consumption by mmagician · Pull Request #2424 · 0xMiden/protocol

mmagician · 2026-02-10T18:56:55Z

Implements Local Exit Tree (LET) frontier management in the bridge_out component.

Changes:

store the frontier (32 nodes) of the Local Exit Tree in the bridge contract
- uses a double-array data structure for convenience, with the map as the underlying storage slot
store the root as two value slots (low, high)
store the number of leaves in a single value slot
after computing the leaf value in feat(AggLayer bridge-out e2e #1): process bridging-out data and load LeafData to memory #2425, process the leaf:
1. load the existing LET frontier to memory
2. call append_and_update_frontier to update the frontier in-memory and obtain the root
3. write back the frontier from memory to storage
4. save the obtained root and number of leaves to storage

cursor · 2026-02-10T18:56:57Z

Cursor Agent can help with this pull request. Just @cursor in comments and I'll start working on changes in this branch.
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crates/miden-agglayer/asm/bridge/bridge_out.masm

Copilot

Pull request overview

Implements Local Exit Tree (LET) persistence for AggLayer bridge-out by storing the LET frontier and associated metadata in the AggLayerBridge account storage, and validating the resulting Local Exit Root against Solidity-generated vectors.

Changes:

Add dedicated bridge account storage slots for LET root (lo/hi) and leaf count, alongside the existing LET map slot.
Update bridge_out.masm to load the LET frontier from storage, append a leaf via append_and_update_frontier, and persist the updated frontier/root/leaf-count back to storage.
Extend Solidity/Rust compatibility vectors and tests to include destination parameters and amounts, and assert the computed Local Exit Root matches Solidity.

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
crates/miden-testing/tests/agglayer/mod.rs	Exposes `mmr_frontier` module for cross-test reuse.
crates/miden-testing/tests/agglayer/mmr_frontier.rs	Makes Solidity vector JSON/static data public and extends vector schema (amounts + destination fields).
crates/miden-testing/tests/agglayer/bridge_out.rs	Adds a test asserting Local Exit Root after B2AGG processing matches Solidity vector root.
crates/miden-agglayer/src/lib.rs	Extends bridge account builder with LET root/leaf-count value slots in addition to the LET map slot.
crates/miden-agglayer/solidity-compat/test/MMRTestVectors.t.sol	Updates vector generation to `DepositContractV2`, includes destination params and amounts, and generates leaf values via `getLeafValue`.
crates/miden-agglayer/solidity-compat/test-vectors/mmr_frontier_vectors.json	Updates embedded vectors to new leaf/root set and includes amounts + destination fields.
crates/miden-agglayer/solidity-compat/foundry.lock	Adds OZ upgradeable dependency required by updated Solidity contracts.
crates/miden-agglayer/asm/bridge/bridge_out.masm	Implements LET frontier load/append/store, plus root and leaf-count persistence.

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crates/miden-testing/tests/agglayer/bridge_out.rs

crates/miden-agglayer/src/lib.rs

crates/miden-agglayer/asm/bridge/bridge_out.masm

crates/miden-agglayer/solidity-compat/test/MMRTestVectors.t.sol

The add.N values should all be add.1 (incrementing the running pointer by 1 each time), not add.1, add.2, add.3, add.4 which caused addresses to skip (P, P+1, P+3, P+6, P+10 instead of P, P+1, P+2, P+3, P+4). Also includes byte-order fixes (u256_le_to_abi, swap_u32_bytes for originNetwork and leafType) and test infrastructure for verifying the root against Solidity vectors. Status: the MMR root computation via call is verified correct (test_mmr_append_via_call passes). The write_address_to_memory fix changed the bridge_out root. Still investigating a remaining mismatch related to u256_le_to_abi + mem_store_double_word_unaligned interaction. Co-authored-by: marti <marti@hungrycats.studio>

Apply suggestions from code review Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

…sor-bridge-out-component-implementation-details-5737

partylikeits1983 · 2026-02-17T10:58:18Z

crates/miden-agglayer/asm/bridge/bridge_out.masm

 use miden::protocol::active_note
+use miden::protocol::active_account
+use miden::protocol::native_account
 use miden::protocol::note
 use miden::standards::note_tag
+use miden::standards::data_structures::double_word_array
 use miden::protocol::output_note
 use miden::core::crypto::hashes::keccak256
 use miden::core::crypto::hashes::rpo256
 use miden::core::word
 use miden::agglayer::utils
 use miden::agglayer::asset_conversion
 use miden::agglayer::crypto_utils
+use miden::agglayer::mmr_frontier32_keccak


I wish these imports were autoformatted to be in alphabetical order since there are so many imports. My old masm formatter would do this, but its out of date with the latest masm syntax.

crates/miden-agglayer/asm/bridge/bridge_out.masm

partylikeits1983

Looks good! Just want to figure out what is going on here: https://github.com/0xMiden/miden-base/pull/2424/changes#r2816492107

before I leave an approval, but otherwise this is great!

Signed-off-by: Marti <marti@miden.team>

Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team>

Signed-off-by: Marti <marti@miden.team>

…sor-bridge-out-component-implementation-details-5737

…t-implementation-details-5737

partylikeits1983

Looks good! Thanks for addressing https://github.com/0xMiden/miden-base/pull/2424/changes#r2816492107

…d update it upon `B2AGG` consumption (0xMiden#2424) * chore: unify b2agg note storage layout with claim note * chore: clarify destinationAddress in CLAIM note * feat: mem_store_double_word_unaligned * feat: compute leaf value for bridging out * chore: update comment about origin network ID * fix: write_address_to_memory had incorrect address arithmetic The add.N values should all be add.1 (incrementing the running pointer by 1 each time), not add.1, add.2, add.3, add.4 which caused addresses to skip (P, P+1, P+3, P+6, P+10 instead of P, P+1, P+2, P+3, P+4). Also includes byte-order fixes (u256_le_to_abi, swap_u32_bytes for originNetwork and leafType) and test infrastructure for verifying the root against Solidity vectors. Status: the MMR root computation via call is verified correct (test_mmr_append_via_call passes). The write_address_to_memory fix changed the bridge_out root. Still investigating a remaining mismatch related to u256_le_to_abi + mem_store_double_word_unaligned interaction. Co-authored-by: marti <marti@hungrycats.studio> * fix: handling of dest address and ID in B2AGG * feat: reverse_limbs_and_change_byte_endianness * chore: integrate byte and limb swapping to bridging * fix: swap origin net ID endianness; rearrange mem writes Apply suggestions from code review Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> * chore: pad mem with zeros after metadata * feat: store LET frontier in double-word array * feat: frontier test generation from param"d leaves * feat: verify computed LER against expected root * write leaf"s amounts to JSON * fix: compare LET by elements, rev elements per word * chore: Replace `unwrap()` with `expect()` for StorageSlotName parsing (0xMiden#2451) * Initial plan * chore: replace unwrap() with expect() for storage slot names Co-authored-by: mmagician <8402446+mmagician@users.noreply.github.com> --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: mmagician <8402446+mmagician@users.noreply.github.com> * Update crates/miden-testing/tests/agglayer/bridge_out.rs Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> * chore: move (de)ser logic to test_utils * chore: organize test_utils better Signed-off-by: Marti <marti@miden.team> * chore: serialize amounts as strings in mmr test vecs Signed-off-by: Marti <marti@miden.team> * test bridge_out frontier persistence across two consumes Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team> * fix bridge_out frontier reload num_leaves endianness Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team> * test bridge_out with shared multi-note helper and 32-leaf case Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team> * refactor bridge_out coverage to direct 32-leaf burn flow Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team> * refactor MMR vectors to seeded per-leaf destinations Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team> * chore: cleanup tests Signed-off-by: Marti <marti@miden.team> --------- Signed-off-by: Marti <marti@miden.team> Co-authored-by: Cursor Agent <cursoragent@cursor.com> Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Co-authored-by: Copilot <198982749+Copilot@users.noreply.github.com>

igamigo added the pr-from-maintainers PRs that come from internal contributors or integration partners. They should be given priority label Feb 10, 2026

mmagician linked an issue Feb 10, 2026 that may be closed by this pull request

AggLayer: maintain proper tracking of LER in the bridge via MMR frontier #2345

Closed

mmagician mentioned this pull request Feb 10, 2026

feat(AggLayer bridge-out e2e #1): process bridging-out data and load LeafData to memory #2425

Merged

mmagician changed the title ~~Bridge_out component implementation details~~ feat(AggLayer): store Local Exit Tree in AggLayerBridge contract and append leaves to it upon B2AGG note processing Feb 10, 2026

mmagician added the agglayer PRs or issues related to AggLayer bridging integration label Feb 10, 2026

mmagician commented Feb 11, 2026

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mmagician force-pushed the mmagician-cursor-bridge-out-component-implementation-details-5737 branch 4 times, most recently from 4e0c724 to ba44bbb Compare February 12, 2026 09:23

mmagician marked this pull request as ready for review February 12, 2026 09:25

mmagician force-pushed the mmagician-bridge-out-store-frontier branch from 1266876 to 8303a1a Compare February 12, 2026 10:46

mmagician force-pushed the mmagician-cursor-bridge-out-component-implementation-details-5737 branch from ba44bbb to c72720b Compare February 12, 2026 10:48

mmagician requested a review from Copilot February 12, 2026 11:00

Copilot started reviewing on behalf of mmagician February 12, 2026 11:01 View session

mmagician mentioned this pull request Feb 12, 2026

feat(AggLayer): faucet registry #2426

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Copilot AI reviewed Feb 12, 2026

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mmagician and others added 11 commits February 15, 2026 15:04

chore: unify b2agg note storage layout with claim note

3167760

chore: clarify destinationAddress in CLAIM note

62d903b

feat: mem_store_double_word_unaligned

ea5c09b

feat: compute leaf value for bridging out

2c7d070

chore: update comment about origin network ID

b82f071

fix: handling of dest address and ID in B2AGG

5286915

feat: reverse_limbs_and_change_byte_endianness

4f58246

chore: integrate byte and limb swapping to bridging

78b8ba9

fix: swap origin net ID endianness; rearrange mem writes

5a91cac

Apply suggestions from code review Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

chore: pad mem with zeros after metadata

c011f8d

mmagician force-pushed the mmagician-bridge-out-store-frontier branch from 8303a1a to c011f8d Compare February 15, 2026 15:06

mmagician added 2 commits February 16, 2026 16:13

Merge branch 'mmagician-bridge-out-store-frontier' into mmagician-cur…

e37cb44

…sor-bridge-out-component-implementation-details-5737

chore: move (de)ser logic to test_utils

29776a7

mmagician requested a review from partylikeits1983 February 16, 2026 18:31

partylikeits1983 reviewed Feb 17, 2026

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partylikeits1983 reviewed Feb 17, 2026

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mmagician force-pushed the mmagician-cursor-bridge-out-component-implementation-details-5737 branch from 75a75db to 05d206e Compare February 17, 2026 18:41

mmagician and others added 8 commits February 17, 2026 19:43

chore: organize test_utils better

fc7d332

Signed-off-by: Marti <marti@miden.team>

chore: serialize amounts as strings in mmr test vecs

c06b6d5

Signed-off-by: Marti <marti@miden.team>

test bridge_out frontier persistence across two consumes

4d71785

Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team>

fix bridge_out frontier reload num_leaves endianness

857d718

Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team>

test bridge_out with shared multi-note helper and 32-leaf case

ed8a052

Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team>

refactor bridge_out coverage to direct 32-leaf burn flow

bf8991d

Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team>

refactor MMR vectors to seeded per-leaf destinations

afc240c

Co-authored-by: marti <marti@hungrycats.studio> Signed-off-by: Marti <marti@miden.team>

chore: cleanup tests

3bfb9d3

Signed-off-by: Marti <marti@miden.team>

mmagician force-pushed the mmagician-cursor-bridge-out-component-implementation-details-5737 branch from 2698ce5 to 3bfb9d3 Compare February 17, 2026 19:43

mmagician requested a review from partylikeits1983 February 17, 2026 19:44

mmagician added 2 commits February 18, 2026 10:09

Merge branch 'agglayer-new' into mmagician-bridge-out-store-frontier

1845253

Merge branch 'mmagician-bridge-out-store-frontier' into mmagician-cur…

37ba1f1

…sor-bridge-out-component-implementation-details-5737

Base automatically changed from mmagician-bridge-out-store-frontier to agglayer-new February 18, 2026 10:23

Merge branch 'agglayer-new' into mmagician-cursor-bridge-out-componen…

4f9d96b

…t-implementation-details-5737

mmagician added the no changelog This PR does not require an entry in the `CHANGELOG.md` file label Feb 18, 2026

Merge branch 'agglayer-new' into mmagician-cursor-bridge-out-componen…

5a85998

…t-implementation-details-5737

partylikeits1983 approved these changes Feb 18, 2026

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mmagician merged commit b1c483b into agglayer-new Feb 18, 2026
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mmagician deleted the mmagician-cursor-bridge-out-component-implementation-details-5737 branch February 18, 2026 13:06

mmagician mentioned this pull request Feb 19, 2026

AggLayer: maintain proper tracking of LER in the bridge via MMR frontier #2345

Closed

mmagician changed the title ~~feat(AggLayer bridge-out #2): store Local Exit Tree in AggLayerBridge contract and update it upon B2AGG consumption~~ feat(AggLayer bridge-out e2e #2): store Local Exit Tree in AggLayerBridge contract and update it upon B2AGG consumption Feb 24, 2026

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feat(AggLayer bridge-out e2e #2): store Local Exit Tree in `AggLayerBridge` contract and update it upon `B2AGG` consumption#2424

feat(AggLayer bridge-out e2e #2): store Local Exit Tree in `AggLayerBridge` contract and update it upon `B2AGG` consumption#2424
mmagician merged 33 commits intoagglayer-newfrom
mmagician-cursor-bridge-out-component-implementation-details-5737

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