Localnet: add support for Supernova by andreibancioiu · Pull Request #560 · multiversx/mx-sdk-py-cli

andreibancioiu · 2025-11-24T13:00:27Z

Here, we attempt to make the localnet compatible with the Node pre & post-Supernova. This should not be a breaking change.

In Supernova, EpochStartConfig.RoundsPerEpoch and EpochStartConfig.MinRoundsBetweenEpochs are dropped. In turn, the parameters are moved to ChainParametersByEpoch.

We introduce two new (optional) localnet parameters: rounds_per_epoch_in_supernova and round_duration_milliseconds_in_supernova. They are used to patch Node's config.toml as depicted below:

ChainParametersByEpoch = [
    { EnableEpoch = 0, RoundDuration = <round_duration_milliseconds>, RoundsPerEpoch = <rounds_per_epoch>, ... },
    { EnableEpoch = 1, RoundDuration = <round_duration_milliseconds>, RoundsPerEpoch = <rounds_per_epoch>, ... },
    { EnableEpoch = 2, RoundDuration = <round_duration_milliseconds_in_supernova>, RoundsPerEpoch = <rounds_per_epoch_in_supernova>, ... },
]

In the future, some time after the release of Supernova, we should drop this cumbersome (but necessary at this moment) logic from mxpy.

References:

andreibancioiu · 2025-11-24T13:04:25Z

multiversx_sdk_cli/localnet/node_config_toml.py


 def patch_enable_epochs(data: ConfigDict, config: ConfigRoot):
    enable_epochs = data["EnableEpochs"]
-    enable_epochs["SCDeployEnableEpoch"] = 0


See https://github.com/multiversx/mx-chain-go/blob/master/cmd/node/config/enableEpochs.toml.

andreibancioiu · 2025-11-24T15:36:18Z

multiversx_sdk_cli/localnet/nodes_setup_json.py


    return {
        "startTime": config.genesis_time(),
-        "roundDuration": config.general.round_duration_milliseconds,


Dropped some time ago.

https://github.com/multiversx/mx-chain-go/blob/master/cmd/node/config/nodesSetup.json

andreibancioiu · 2025-11-24T15:36:52Z

multiversx_sdk_cli/localnet/step_config.py

-        genesis_smart_contracts_json.patch(data, config)
-        utils.write_json_file(genesis_smart_contracts_file, data)
+
+        node_config_data = utils.read_toml_file(node_config_file)


Trivial refactoring, so that we can read & pass supernova_activation_epoch to patch_config more easily.

andreibancioiu · 2025-11-24T15:40:48Z

multiversx_sdk_cli/localnet/node_config_toml.py

+            item["RoundDuration"] = config.general.round_duration_milliseconds_in_supernova
+            item["RoundsPerEpoch"] = config.general.rounds_per_epoch_in_supernova


Once Supernova is active, we use the new localnet configuration entries: round_duration_milliseconds_in_supernova and rounds_per_epoch_in_supernova.

andreibancioiu · 2025-11-24T15:41:26Z

multiversx_sdk_cli/localnet/node_config_toml.py

    chain_parameters_by_epoch = data["GeneralSettings"].get("ChainParametersByEpoch", [])

-    if chain_parameters_by_epoch:
-        # For convenience, keep a single entry ...


Tricky. Changed to use the whole collection of ChainParametersByEpoch entries.

andreibancioiu · 2025-11-24T15:52:42Z

multiversx_sdk_cli/localnet/node_config_toml.py



-def patch_config(data: ConfigDict, config: ConfigRoot):
+def patch_config(data: ConfigDict, config: ConfigRoot, supernova_activation_epoch: Optional[int] = None):


The new argument is used when iterating over ChainParametersByEpoch.

andreibancioiu · 2025-11-27T10:30:11Z

multiversx_sdk_cli/localnet/node_config_toml.py

    )
+
+
+def patch_enable_rounds(data: ConfigDict, config: ConfigRoot, enable_epochs_config: ConfigDict):


See:

https://github.com/multiversx/mx-chain-go/blob/feat/supernova-async-exec/cmd/node/config/enableRounds.toml.

andreibancioiu · 2025-12-02T05:57:47Z

multiversx_sdk_cli/localnet/constants.py

+
+# See https://github.com/multiversx/mx-chain-go/blob/master/cmd/node/config/config.toml.
+ROUNDS_PER_EPOCH_TO_MIN_ROUNDS_BETWEEN_EPOCHS_RATIO = 4
+NUM_ROUNDS_BETWEEN_SUPERNOVA_ACTIVATION_EPOCH_AND_ACTIVATION_ROUND = 20


See https://github.com/multiversx/mx-chain-go/blob/rc/supernova/cmd/node/config/enableRounds.toml.

andreibancioiu · 2025-12-02T05:58:56Z

multiversx_sdk_cli/localnet/node_config_toml.py

+        enable_epoch = item["StartEpoch"]
+
+        if enable_epoch == supernova_activation_epoch:
+            item["StartRound"] = _compute_supernova_activation_round(config, supernova_activation_epoch)


See:

https://github.com/multiversx/mx-chain-go/blob/feat/supernova-async-exec/cmd/node/config/config.toml#L97

https://github.com/multiversx/mx-chain-go/blob/feat/supernova-async-exec/cmd/node/config/enableRounds.toml

Copilot

Pull request overview

This PR adds support for the Supernova upgrade to the localnet configuration, ensuring backward compatibility with pre-Supernova nodes. The implementation introduces optional localnet parameters for Supernova-specific epoch and round configurations while maintaining support for the legacy configuration system.

Key changes:

Added two new optional parameters (rounds_per_epoch_in_supernova and round_duration_milliseconds_in_supernova) to configure epoch timing in Supernova
Modified node configuration patching to conditionally apply Supernova settings based on SupernovaEnableEpoch detection
Removed redundant fields from nodesSetup.json that are now handled by ChainParametersByEpoch

Reviewed changes

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

Show a summary per file

File	Description
pyproject.toml	Version bump to 11.3.0
multiversx_sdk_cli/localnet/config_general.py	Added two new parameters for Supernova epoch/round configuration and updated override logic
multiversx_sdk_cli/localnet/config_default.py	Set default values for Supernova parameters (300 rounds per epoch, 2000ms round duration)
multiversx_sdk_cli/localnet/constants.py	Added constants for epoch/round ratio calculation and Supernova activation round offset
multiversx_sdk_cli/localnet/node_config_toml.py	Implemented conditional logic to apply Supernova configuration, added enable rounds patching, and helper function for activation round calculation
multiversx_sdk_cli/localnet/step_config.py	Refactored config patching to batch file reads/writes and added enable_rounds_config handling
multiversx_sdk_cli/localnet/nodes_setup_json.py	Removed fields now managed by ChainParametersByEpoch (roundDuration, consensusGroupSize, etc.)

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multiversx_sdk_cli/localnet/node_config_toml.py

multiversx_sdk_cli/localnet/config_general.py

multiversx_sdk_cli/localnet/node_config_toml.py

popenta · 2025-12-02T08:23:33Z

multiversx_sdk_cli/localnet/config_default.py

    round_duration_milliseconds=6000,
+    # For the purpose of the localnet, we'll have 3x for Supernova (by default).
+    rounds_per_epoch_in_supernova=300,
+    round_duration_milliseconds_in_supernova=2000,


Shouldn't we have the actual duration of the round (600ms)?

Good question!

I've chosen 2 seconds by default in order to demand less resources from the host machine (development machine).

All good?

Fine with me. We should at least document that the localnet starts with a roundtime of 2s and we should show people where to change in case they want to run a 600ms round, replicating mainnet config.

andreibancioiu added 2 commits November 24, 2025 14:59

Localnet: sketch new configuration parameters (for Supernova).

bd237cd

Simplify "patch_enable_epochs()".

049cb40

andreibancioiu commented Nov 24, 2025

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andreibancioiu added 3 commits November 24, 2025 16:28

Patch node config toml wrt. enable epochs toml.

71a58eb

Fix node config.

92cbcf8

Adjust constant.

a69bf61

andreibancioiu self-assigned this Nov 24, 2025

Drop unused parameters from nodes setup.

1cb258c

andreibancioiu commented Nov 24, 2025

View reviewed changes

Fix after self-review.

b765d63

andreibancioiu commented Nov 24, 2025

View reviewed changes

andreibancioiu marked this pull request as ready for review November 24, 2025 15:52

popenta previously approved these changes Nov 25, 2025

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mradian1 previously approved these changes Nov 25, 2025

View reviewed changes

Patch "enable rounds", as well.

a57fa49

andreibancioiu dismissed stale reviews from mradian1 and popenta via a57fa49 November 25, 2025 15:13

Patch "VersionsByEpoch" in config.toml.

cfb3a86

andreibancioiu commented Nov 27, 2025

View reviewed changes

andreibancioiu commented Dec 2, 2025

View reviewed changes

Fix after self-review.

22f5b6f

popenta requested a review from Copilot December 2, 2025 08:10

Copilot started reviewing on behalf of popenta December 2, 2025 08:11 View session

Copilot finished reviewing on behalf of popenta December 2, 2025 08:14

Copilot AI reviewed Dec 2, 2025

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popenta reviewed Dec 2, 2025

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Fix after review.

54511a7

mradian1 approved these changes Dec 2, 2025

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popenta approved these changes Dec 2, 2025

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andreibancioiu merged commit 4cdaeff into main Dec 2, 2025
12 of 14 checks passed

		item["RoundDuration"] = config.general.round_duration_milliseconds_in_supernova
		item["RoundsPerEpoch"] = config.general.rounds_per_epoch_in_supernova



		def patch_config(data: ConfigDict, config: ConfigRoot):
		def patch_config(data: ConfigDict, config: ConfigRoot, supernova_activation_epoch: Optional[int] = None):

		)


		def patch_enable_rounds(data: ConfigDict, config: ConfigRoot, enable_epochs_config: ConfigDict):

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andreibancioiu commented Nov 24, 2025 •

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