DO NOT MERGE until maturity modulation validated in mainnet feat(governance): switch spawning and disbursement to locally computed maturity modulation by jasonz-dfinity · Pull Request #9848 · dfinity/ic

jasonz-dfinity · 2026-04-13T22:27:43Z

Why

The previous PR added local maturity modulation computation. This PR switches the actual consumers to use it.

https://dfinity.atlassian.net/browse/NNS1-4319

What

maybe_spawn_neurons() reads from icp_xdr_rate_history.current_maturity_modulation_permyriad instead of cached_daily_maturity_modulation_basis_points
try_finalize_maturity_disbursement() reads from the same new source
TLA state export updated accordingly
Tests updated to set up icp_xdr_rate_history instead of the old field

The old CMC-polled fields are not yet removed; that happens in the next PR.

PR Chain

⬅️ Previous: feat(governance): derive Mission 70 maturity modulation from XRC price history #9847
➡️ Next: refactor(governance): remove old CMC-based maturity modulation and XDR rate polling #9877

Testing

Existing disburse_maturity and maybe_spawn_neurons tests updated and passing.

Copilot

Pull request overview

This PR aims to switch governance maturity-modulation consumers (neuron spawning + maturity disbursement finalization) to read the locally computed maturity modulation value, and updates TLA export + tests accordingly.

Changes:

Update maybe_spawn_neurons and try_finalize_maturity_disbursement to read maturity modulation from a new heap-data source.
Update TLA global export to reflect the new maturity-modulation source.
Update disburse-maturity tests to set up the new maturity-modulation source.

Reviewed changes

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

Show a summary per file

File	Description
rs/nns/governance/src/timer_tasks/mod.rs	Adds imports intended for XRC-related logic (currently unused in this module).
rs/nns/governance/src/governance/tla/mod.rs	Switches TLA export of cached maturity modulation to the new source.
rs/nns/governance/src/governance/disburse_maturity_tests.rs	Updates test setup to populate the new maturity-modulation source.
rs/nns/governance/src/governance/disburse_maturity.rs	Switches maturity disbursement finalization to read modulation from the new source.
rs/nns/governance/src/governance.rs	Switches neuron spawning to read modulation from the new source.

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…m-clients

…e history

…e sum

…name to duration_until_next_midnight_utc

github-actions

This pull request changes code owned by the Governance team. Therefore, make sure that
you have considered the following (for Governance-owned code):

Update unreleased_changelog.md (if there are behavior changes, even if they are
non-breaking).
Are there BREAKING changes?
Is a data migration needed?
Security review?

How to Satisfy This Automatic Review

Go to the bottom of the pull request page.
Look for where it says this bot is requesting changes.
Click the three dots to the right.
Select "Dismiss review".
In the text entry box, respond to each of the numbered items in the previous
section, declare one of the following:

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$REASON_WHY_NO_NEED. E.g. for unreleased_changelog.md, "No
canister behavior changes.", or for item 2, "Existing APIs
behave as before.".

Brief Guide to "Externally Visible" Changes

"Externally visible behavior change" is very often due to some NEW canister API.

Changes to EXISTING APIs are more likely to be "breaking".

If these changes are breaking, make sure that clients know how to migrate, how to
maintain their continuity of operations.

If your changes are behind a feature flag, then, do NOT add entrie(s) to
unreleased_changelog.md in this PR! But rather, add entrie(s) later, in the PR
that enables these changes in production.

Reference(s)

For a more comprehensive checklist, see here.

GOVERNANCE_CHECKLIST_REMINDER_DEDUP

…d maturity modulation

…ory, remove unused imports

daniel-wong-dfinity-org

I would put this behind a flag.

tmu0 · 2026-04-24T09:09:12Z

        };

        // Sanity check that the maturity modulation returned is within bounds.
        if !VALID_MATURITY_MODULATION_BASIS_POINTS_RANGE.contains(&maturity_modulation) {


Range still has the old values

tmu0 · 2026-04-24T09:12:32Z


        let now_seconds = self.env.now();
-        let maturity_modulation = match self.heap_data.cached_daily_maturity_modulation_basis_points
+        let maturity_modulation = match self


Maybe we should add another sanity check that makes sure that the maturity modulation value is the one for the current day (also in the disburse maturity case)?

…e history (dfinity#9847) ## Why Previously, Governance relied on CMC (Cycles Minting Canister) as a middleman for ICP price data used in maturity modulation. This PR cuts out the middleman by having Governance fetch ICP/XDR rates directly from the Exchange Rate Canister (XRC) and derive Mission 70 maturity modulation locally. https://dfinity.atlassian.net/browse/NNS1-4319 ## What - `IcpPriceHistory`: bounded sorted vector of up to 365 daily ICP/XDR rates in Governance state (new proto field 33) - `UpdateIcpXdrRateRelatedData`: timer task that fetches rates directly from XRC, backfills the last 365 days on first upgrade (~30 min at 5-second intervals), then switches to daily fetches aligned to UTC midnight; recomputes Mission 70 maturity modulation after each update - The existing CMC-polled maturity modulation remains active for spawning/disbursement (switchover is in a later PR) ### PR Chain - ⬅️ Previous: dfinity#9846 - ➡️ Next: dfinity#9848, dfinity#9879 ## Testing Unit tests for the price history buffer, maturity modulation computation, and UTC midnight timer logic.

jasonz-dfinity added the feat label Apr 13, 2026

jasonz-dfinity requested a review from Copilot April 13, 2026 22:30

Copilot started reviewing on behalf of jasonz-dfinity April 13, 2026 22:30 View session

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This was referenced Apr 14, 2026

feat(governance): derive Mission 70 maturity modulation from XRC price history #9847

Merged

refactor(governance): remove old CMC-based maturity modulation and XDR rate polling #9877

Draft

jasonz-dfinity added 3 commits April 15, 2026 11:04

feat: extract shared ExchangeRateCanisterClient into ic-nervous-syste…

6dbfea0

…m-clients

address PR feedback: reflow long doc comment

67e7b8d

address Copilot feedback: fix doc comment and document pow safety

7491aee

jasonz-dfinity force-pushed the jason/NNS1-4319-compute-maturity-modulation branch from 0724790 to 9a31ba9 Compare April 15, 2026 19:27

jasonz-dfinity force-pushed the jason/NNS1-4319-switch-maturity-modulation branch from 2263afa to f607ce6 Compare April 15, 2026 19:27

jasonz-dfinity added 3 commits April 15, 2026 14:14

fix clippy: separate literal suffix with underscore

76e96e7

feat(governance): derive Mission 70 maturity modulation from XRC pric…

85f5793

…e history

address Copilot feedback: validate XRC timestamp, use u128 for averag…

a7108f0

…e sum

jasonz-dfinity force-pushed the jason/NNS1-4319-compute-maturity-modulation branch from 9a31ba9 to a7108f0 Compare April 15, 2026 21:29

jasonz-dfinity force-pushed the jason/NNS1-4319-switch-maturity-modulation branch from f607ce6 to 9da51a1 Compare April 15, 2026 21:29

address PR feedback: pass XRC client explicitly to schedule_tasks, re…

3f2c828

…name to duration_until_next_midnight_utc

jasonz-dfinity force-pushed the jason/NNS1-4319-switch-maturity-modulation branch from 9da51a1 to 8577ae1 Compare April 15, 2026 22:29

jasonz-dfinity marked this pull request as ready for review April 15, 2026 22:32

jasonz-dfinity requested a review from a team as a code owner April 15, 2026 22:32

github-actions Bot requested changes Apr 15, 2026

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jasonz-dfinity changed the title ~~feat(governance): switch spawning and disbursement to locally computed maturity modulation~~ DO NOT MERGE until maturity modulation validated in mainnet feat(governance): switch spawning and disbursement to locally computed maturity modulation Apr 15, 2026

jasonz-dfinity added 3 commits April 15, 2026 21:44

fix tests: mock XRC clients must echo requested timestamp

1455d28

feat(governance): switch spawning and disbursement to locally compute…

13a2bba

…d maturity modulation

fix compilation: use maturity_modulation instead of icp_xdr_rate_hist…

bc807c4

…ory, remove unused imports

jasonz-dfinity force-pushed the jason/NNS1-4319-switch-maturity-modulation branch from 8577ae1 to bc807c4 Compare April 16, 2026 05:21

daniel-wong-dfinity-org reviewed Apr 16, 2026

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tmu0 reviewed Apr 24, 2026

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jasonz-dfinity force-pushed the jason/NNS1-4319-compute-maturity-modulation branch from 1455d28 to 876292a Compare May 5, 2026 23:05

Base automatically changed from jason/NNS1-4319-compute-maturity-modulation to master May 7, 2026 17:01

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DO NOT MERGE until maturity modulation validated in mainnet feat(governance): switch spawning and disbursement to locally computed maturity modulation#9848

DO NOT MERGE until maturity modulation validated in mainnet feat(governance): switch spawning and disbursement to locally computed maturity modulation#9848
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jasonz-dfinity commented Apr 13, 2026 •

edited

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jasonz-dfinity commented Apr 13, 2026 •

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