feat(remote-feature-flag-controller): segment threshold flags by metaMetricsFlags with canonical ID default

[asalsys]

Summary

• Add required getCanonicalProfileId constructor callback and metaMetricsFlags map for threshold flag segmentation.
• Threshold flags use canonical profile ID by default; flags whose names are present in metaMetricsFlags use MetaMetrics ID instead.
• Generalize threshold calculation to hash the selected segmentation ID while preserving the existing deterministic bucketing behavior.
• Pass the new segmentation options through @metamask/wallet remote feature flag controller initialization.

Segmentation Behavior

Flag configuration	Identifier used	Constructor callback
Flag name absent from metaMetricsFlags	Canonical profile ID	getCanonicalProfileId()
Flag name present in metaMetricsFlags	MetaMetrics ID	getMetaMetricsId()

If the selected identifier is empty, threshold arrays are preserved as-is and not processed.

Example threshold config using canonical segmentation by default:

{
"myCanonicalFlag": [
{
"name": "groupA",
"scope": { "type": "threshold", "value": 0.5 },
"value": "valueA"
},
{
"name": "groupB",
"scope": { "type": "threshold", "value": 1.0 },
"value": "valueB"
}
]
}

Example controller setup for a flag that should keep MetaMetrics segmentation:

newRemoteFeatureFlagController({// ...
getMetaMetricsId,
getCanonicalProfileId,metaMetricsFlags: {legacyMetaMetricsFlag: true,},});

Migration

Consumers must pass getCanonicalProfileId for threshold flags that should use canonical profile segmentation, which is now the default for flags absent from metaMetricsFlags.

Existing threshold flags that must keep MetaMetrics-based bucketing should be listed in metaMetricsFlags and continue to provide getMetaMetricsId.

Test plan

• yarn workspace @metamask/remote-feature-flag-controller run jest --no-coverage src/utils/user-segmentation-utils.test.ts src/remote-feature-flag-controller.test.ts
• Threshold flags absent from metaMetricsFlags use getCanonicalProfileId for segmentation
• Threshold flags present in metaMetricsFlags use getMetaMetricsId for segmentation
• Threshold arrays are preserved when the selected identifier is empty
• Threshold cache entries use the selected segmentation ID and stale entries are cleaned up when flags are removed from the server response

Related

• Documentation: MetaMask/contributor-docs#176
• Ticket - https://consensyssoftware.atlassian.net/browse/MCWP-662

---

Note

Medium Risk
Breaking constructor and experiment-assignment change: existing threshold flags will re-bucket unless listed in metaMetricsFlags. Not auth or payment logic, but it can change live A/B group membership.

Overview
Breaking: threshold flags now bucket by canonical profile ID by default instead of MetaMetrics ID. RemoteFeatureFlagController requires getCanonicalProfileId; flags listed in optional metaMetricsFlags still use getMetaMetricsId.

Hash-based assignment hashes the chosen segmentation ID. If that ID is empty, the threshold array is left unprocessed. Explicit MetaMetrics ID targeting is unchanged. Threshold cache keys and stale-entry cleanup cover both identifiers.

@metamask/wallet forwards the new options (optional; empty-string default for canonical ID). Consumers that need the old MetaMetrics bucketing must list those flag names in metaMetricsFlags.

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[NicolasMassart]

Two comments, one blocking and a nit.

[mcmire]

Some comments.

[mcmire]

LGTM!

[davidmurdoch]

I don't really understand why this change is needed, but have left a comment about the API anyway.

[davidmurdoch]

I don't understand the reason for this. but from a code and api standpoint, it looks good.

[cursor]

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