feat(gas-keys): stabilize gas keys at protocol version 85 by darioush · Pull Request #15183 · near/nearcore

darioush · 2026-02-23T21:30:15Z

Gas Keys (NEP-611)

Gas keys are a new type of access key that carries a pre-funded NEAR balance and multiple independent nonce sequences. When a transaction is signed with a gas key, gas costs are deducted from the gas key's balance rather than the signer's account balance (deposits like NEAR transfers still come from the account).

Why do we need gas keys?

Enabling SPICE without a DoS vector. The SPICE project (Separation of Execution from Consensus) decouples transaction execution from block production: transactions are included in blocks first, and executed asynchronously later. This means chunk producers can no longer verify account balances at inclusion time. An attacker could drain an account's balance in one transaction, then flood the chain with many transactions signed by that account. All would be accepted (since execution hasn't caught up), consuming block space for free when they inevitably fail. Gas keys close this gap by requiring gas to be pre-committed in the key itself, so chunk producers can verify gas availability without access to the latest state.
Parallel transaction submission. Today, programmatic users who submit many transactions in parallel must manage multiple access keys (each with its own nonce sequence). A gas key supports up to 1,024 independent nonce slots via a single key, removing that complexity.

Context

Testing and QA

unit tests
test-loop: https://github.com/near/nearcore/blob/master/test-loop-tests/src/tests/gas_keys.rs
forknet (automated): test(mirror): add gas key test case to offline mirror test #15207
forknet (manual testing, planned)

Checklist

Link to nightly nayduck run: https://nayduck.nearone.org/#/run/4756
Update CHANGELOG.md to include this protocol feature in the Unreleased section.

Copilot

Pull request overview

This PR stabilizes the ProtocolFeature::GasKeys feature by moving it into the stable protocol feature set at protocol version 85, updating stable protocol version constants accordingly, and aligning tests/snapshots/changelog with the new stable behavior.

Changes:

Promote ProtocolFeature::GasKeys to stable at PV 85 and bump STABLE_PROTOCOL_VERSION to 85.
Remove nightly-only ignore gating from test-loop gas key tests so they run on stable.
Update chain snapshot hashes and add a changelog entry documenting GasKeys stabilization.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
test-loop-tests/src/tests/gas_keys.rs	Removes nightly-only ignore gates so GasKeys tests run under stable builds.
core/primitives-core/src/version.rs	Moves GasKeys to stable at PV 85 and bumps `STABLE_PROTOCOL_VERSION` to 85.
chain/chain/src/tests/simple_chain.rs	Updates insta snapshot hashes to reflect the new stable protocol version/feature set.
CHANGELOG.md	Documents GasKeys stabilization in the unreleased protocol changes section.

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Copilot · 2026-02-23T21:58:08Z

 ### Protocol Changes
 * The contract runtime has been upgraded to use the new Wasmtime-based runtime;
 * The contract runtime now allows for bulk memory instructions in Wasm code.
+* Stabilize GasKeys: transactions can now specify a gas key to pay for gas costs separately from the signer's main access key.


The new changelog bullet uses imperative tense ("Stabilize") while the surrounding bullets use past/present perfect ("has been upgraded", "now allows"). Consider rephrasing for consistency (e.g., "GasKeys stabilized" / "GasKeys has been stabilized") and aligning end punctuation with the other entries in this section.

Suggested change

* Stabilize GasKeys: transactions can now specify a gas key to pay for gas costs separately from the signer's main access key.

* GasKeys has been stabilized: transactions can now specify a gas key to pay for gas costs separately from the signer's main access key.

codecov · 2026-02-23T23:00:52Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 69.74%. Comparing base (8539f35) to head (33d4f2b).

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #15183   +/-   ##
=======================================
  Coverage   69.73%   69.74%           
=======================================
  Files         944      944           
  Lines      201033   201032    -1     
  Branches   201033   201032    -1     
=======================================
+ Hits       140193   140202    +9     
+ Misses      56133    56125    -8     
+ Partials     4707     4705    -2

Flag	Coverage Δ
pytests-nightly	`1.12% <ø> (+<0.01%)`	⬆️
unittests	`69.48% <ø> (+0.15%)`	⬆️
unittests-nightly	`69.46% <ø> (+0.01%)`	⬆️

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darioush · 2026-02-25T18:01:46Z

Per our procedures for stabilization, this PR requires additional sign off.
Please take a look @pugachAG, thanks.

https://github.com/near/nearcore/blob/master/docs/practices/protocol_upgrade.md#feature-stabilization

pugachAG

I suggest we stabilize the feature after NEP is fully approved

darioush · 2026-06-01T17:02:30Z

Why some test-loop tests switched to `backwards_compatible_rs_contract`

Gas keys adds three contract host functions (promise_batch_action_transfer_to_gas_key, promise_batch_action_add_gas_key_with_full_access, promise_batch_action_add_gas_key_with_function_call) that the runtime exposes only from protocol version 85. On the test side these are declared under #[cfg(feature = "latest_protocol")], so they live in rs_contract (and nightly_rs_contract), alongside the other stabilized host fns.

The catch: the always-exported call_promise dispatcher references these host fns unconditionally, so the compiled wasm emits them as host imports (unlike e.g. p256_verify, which is declared but never called and therefore dead-code-eliminated). WASM instantiation links imports eagerly — every imported host function must be provided by the host at the protocol version the contract is instantiated at. Below v85 the host does not provide the gas-key imports.

Protocol-upgrade tests that instantiate rs_contract before the upgrade (i.e. at a protocol < 85) therefore fail at link time:

Link Error: unknown or invalid import

The three tests that do this were pointed at backwards_compatible_rs_contract, which is built without latest_protocol and so carries none of the v85 imports. This is the contract the docs already prescribe for protocol-upgrade tests (resharding_v3 uses it):

yield_resume::test_yield_resume_across_protocol_upgrade — calls the contract at old_protocol = InstantPromiseYield - 1 = 82, before upgrading.
cache_warming::slow_test_cache_warming_across_vm_config_change — calls at PROTOCOL_VERSION - 1 = 84, by design (pre-upgrade cache warming).
deterministic_account_id::test_..._pre_fix — runs at FixDelegatedDeterministicStateInit - 1 = 84; its shared TestEnv now picks the contract by version.

Tests that only instantiate the contract at/after the upgrade (≥ 85) — e.g. those in global_contracts_distribution — were left on rs_contract, since the imports resolve fine there. This was verified per-test rather than assumed.

🤖 -- Claude on behalf of Darioush

Copilot

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated 1 comment.

rs_contract now imports the chain_id host fn (latest_protocol), so it no longer links below protocol 85. Point the protocol-upgrade tests that instantiate it pre-upgrade at backwards_compatible_rs_contract. Byte-for-byte identical to the same fix in #15183; kept as a standalone commit so it can be dropped if #15183 lands first.

# Conflicts: # core/primitives-core/src/version.rs

# Conflicts: # core/parameters/src/config_store.rs # core/parameters/src/snapshots/near_parameters__config_store__tests__149.json.snap # core/parameters/src/snapshots/near_parameters__config_store__tests__testnet_149.json.snap

## Summary Implements the [NEP-638](near/NEPs#638) `chain_id` host function, which lets a contract read the chain identifier (e.g. `mainnet`, `testnet`) at runtime instead of hardcoding it or passing it in as an argument. Gated behind protocol version 85. Signature: `chain_id(register_id: u64)` — writes the chain id bytes into the given register. Cost is `base + write_register_base + write_register_byte * num_bytes`; no new gas parameters are introduced (it reuses the existing register-write costs). ## Design notes - The value is fetched lazily through the `External` trait inside the host function (the same pattern as `validator_total_stake`), rather than being pre-populated into `VMContext`. So there is no per-call allocation unless a contract actually calls `chain_id`. `RuntimeExt::chain_id()` reads it from the epoch info provider. - Import gating is handled by `Config::chain_id_host_fn`: pre-v85 the `env.chain_id` import is not exposed, so a contract importing it fails to link. ## Testing - VM logic unit test: `runtime/near-vm-runner/src/logic/tests/context.rs::test_chain_id`. - VM integration test: `runtime/near-vm-runner/src/tests/chain_id_integration.rs` runs `ext_chain_id` through every VM backend (NearVm + Wasmtime) and checks the returned bytes. - e2e test-loop tests: `test-loop-tests/src/tests/chain_id.rs` covers the full transaction → receipt → outcome pipeline — `test_chain_id_returns_chain_id` asserts the genesis chain id at v85, and `test_chain_id_pre_activation_call_fails` confirms a contract importing `env.chain_id` fails to link at protocol 84. - The contract side reuses the shared `test-contract-rs` via a new `ext_chain_id` export, gated `#[cfg(feature = "latest_protocol")]` so it only ships in `rs_contract` (not `backwards_compatible_rs_contract`). ## Notes - Because `rs_contract` now imports `env.chain_id`, it no longer links below protocol 85. Three protocol-upgrade tests that instantiate it pre-upgrade (`cache_warming`, `deterministic_account_id`, `yield_resume`) are pointed at `backwards_compatible_rs_contract`. This fix is byte-for-byte identical to the same change in near#15183 and is kept as a standalone commit so it can be dropped cleanly if near#15183 lands first.

darioush requested a review from a team as a code owner February 23, 2026 21:30

darioush requested review from Copilot, saketh-are and shreyan-gupta and removed request for Copilot and saketh-are February 23, 2026 21:30

darioush force-pushed the darioush/gas-keys/stabilize branch from 4aa89a4 to 0cc3dd4 Compare February 23, 2026 21:55

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VanBarbascu approved these changes Feb 25, 2026

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darioush requested a review from pugachAG February 25, 2026 17:59

pugachAG requested changes Feb 26, 2026

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darioush marked this pull request as draft February 27, 2026 14:21

r-near mentioned this pull request Mar 3, 2026

NEP-611: Pending Transaction Queue & Gas Keys — DevEx library changes near/devex#43

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shreyan-gupta removed their request for review May 12, 2026 21:44

darioush force-pushed the darioush/gas-keys/stabilize branch 3 times, most recently from 285123b to fa95fae Compare June 1, 2026 16:35

feat(gas-keys): stabilize gas keys at protocol version 85

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darioush force-pushed the darioush/gas-keys/stabilize branch from fa95fae to 55b2491 Compare June 1, 2026 16:48

darioush requested a review from Copilot June 1, 2026 16:58

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Comment thread test-loop-tests/src/tests/gas_keys.rs Outdated

address review: fix stale contract comments, changelog tense

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darioush marked this pull request as ready for review June 1, 2026 17:18

darioush requested a review from pugachAG June 1, 2026 17:18

darioush mentioned this pull request Jun 1, 2026

feat: chain_id host function #15589

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Merge remote-tracking branch 'origin/master' into gaskeys-stabilize

33d4f2b

# Conflicts: # core/primitives-core/src/version.rs

pugachAG approved these changes Jun 3, 2026

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darioush enabled auto-merge June 3, 2026 13:21

darioush added this pull request to the merge queue Jun 3, 2026

Merged via the queue into master with commit 2aa23e2 Jun 3, 2026
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darioush deleted the darioush/gas-keys/stabilize branch June 3, 2026 14:18

darioush mentioned this pull request Jun 3, 2026

refactor(test-loop): dedupe contract selection by protocol version #15844

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feat(gas-keys): stabilize gas keys at protocol version 85#15183

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	* Stabilize GasKeys: transactions can now specify a gas key to pay for gas costs separately from the signer's main access key.
	* GasKeys has been stabilized: transactions can now specify a gas key to pay for gas costs separately from the signer's main access key.

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darioush commented Feb 23, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Gas Keys (NEP-611)

Why do we need gas keys?

Context

Testing and QA

Checklist

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darioush commented Jun 1, 2026

Why some test-loop tests switched to backwards_compatible_rs_contract

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Why some test-loop tests switched to `backwards_compatible_rs_contract`