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This overview explains how Boolean feature constraints
and their identities change across model revisions.

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A familiar model name does not guarantee that
a cached result remains valid after a constraint changes.

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Let P mean the premium option is selected and B mean its base option is selected.

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Version one requires premium to imply base.

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A configuration can omit premium, but selecting premium without base violates this rule.

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With premium and base both selected, implication is true.

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With premium selected and base absent, implication is false.

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We have evaluated complete selections under a specified version instead of treating a

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product label as a self-explanatory condition.

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Version two adds a resource requirement for premium.

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The complete rule has changed.

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An earlier satisfying selection must be checked under this revised conjunction before it

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is accepted as current.

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is accepted as current.

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Features form Boolean choices constrained by requires and excludes rules.

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Reusing an artifact across revisions needs exact source
and assumption identity, not just a familiar model name.

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Use Core, Cloud, Local, Analytics and Export.

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Require Core.

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Cloud and Local exclude each other; Analytics
requires Cloud; Export requires Analytics.

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With Core, Cloud and Analytics true, Local
and Export false, the selection is valid.

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In revision two, add Export requires Local.

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A selection enabling Export now conflicts with the
Cloud requirement inherited through Analytics.

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Export now requires Local, but it also requires Cloud through Analytics.

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Cloud and Local exclude each other.

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This is a conceptual revision example, not a deployed product benchmark.

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Retained feature-model lifecycle work keeps cold,

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warm and reload costs separate and does not justify a universal CM default.

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A validity bit, full count and distinct projected
feature count remain different queries.

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Return to the opening premium, base and resource model.

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Here P means premium, B means base, and R means resource.

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Its version two requires both P implies B and P implies R.

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This is separate from the other product model.

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Set P, B and R all to one.

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Premium now has both the base and resource requirements available.

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Each implication returns one, and their conjunction returns one.

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This revised rule is not a blanket rejection of premium configurations; it rejects only selections that violate at least one required clause.

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This case establishes a specific contrast.

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The revised policy accepts this selection.

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Recompute decisions under the current version.

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Keep the input, intermediate values, and conclusion together when comparing it with the previous case.

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The calculated answer belongs to this complete assignment under the stated rule.

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Take premium and base selected but resource absent.

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Version one only checked premium's dependence on base, so it accepted this selection.

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That old result is correct for the old rule.

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The new implication fails because premium is selected while the

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required resource is absent.

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Combining the old successful clause with this zero gives zero.

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The selection is rejected under version two.

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The old final decision cannot stand in for the new one.

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That does not require discarding every compatible unchanged subexpression.

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Track the full rule version and the dependencies of each reusable artifact so that valid

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reuse is distinguished from a stale answer.

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reuse is distinguished from a stale answer.

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Revalidate or invalidate dependent artifacts after a revision.

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Keep validity, full-assignment counts, and projected feature counts distinct.