export type NpmRegistryFailure = {
    kind: 'http-error';
    status: number;
} | {
    kind: 'invalid-response';
} | {
    kind: 'transport-error';
    message: string;
};
export type NpmRegistryFetch = (input: string | URL, init?: RequestInit) => Promise<Pick<Response, 'ok' | 'status' | 'json'>>;
export type NpmVersionResolution = {
    status: 'resolved';
    version: string;
} | {
    status: 'no-target';
    reason: NpmVersionNoTargetReason;
} | {
    status: 'error';
    failure: NpmRegistryFailure;
};
export type NpmDistTagResult = {
    status: 'resolved';
    version: string;
} | {
    status: 'missing';
} | {
    status: 'invalid';
    value: unknown;
} | {
    status: 'error';
    failure: NpmRegistryFailure;
};
export type NpmDistTagClassification = Exclude<NpmDistTagResult, {
    status: 'error';
}>;
export type NpmVersionNoTargetReason = {
    kind: 'missing-channel';
    channel: string;
} | {
    kind: 'invalid-channel-version';
    channel: string;
    version: string;
} | {
    kind: 'prerelease-channel';
    channel: string;
    version: string;
} | {
    kind: 'unacceptable-latest';
    version: string | null;
} | {
    kind: 'no-valid-candidates';
};
export type NpmDistTagsResult = {
    status: 'ok';
    tags: Record<string, unknown>;
} | {
    status: 'error';
    failure: NpmRegistryFailure;
};
/** The sole injected registry boundary used by all target resolvers. */
export type NpmDistTagsLoader = () => Promise<NpmDistTagsResult>;
export declare function decodeNpmDistTags(value: unknown): Record<string, unknown> | null;
export declare function isValidSemver(value: string): boolean;
export declare function isPrerelease(value: string): boolean;
export type ExplicitNpmUpdateTargetDecision = {
    status: 'allowed';
    version: string;
} | {
    status: 'rejected';
    reason: string;
} | {
    status: 'registry-error';
    reason: string;
    failure: NpmRegistryFailure;
};
/** The one pure owner of missing, malformed, and validated dist-tag states. */
export declare function classifyNpmDistTag(tags: Readonly<Record<string, unknown>>, tag: string): NpmDistTagClassification;
/** Canonical npm-registry boundary shared by automatic and explicit updates. */
export declare function fetchNpmDistTags(deps?: {
    fetch?: NpmRegistryFetch;
}): Promise<NpmDistTagsResult>;
export declare function resolveNpmDistTag(tag: string, loadDistTags?: NpmDistTagsLoader): Promise<NpmDistTagResult>;
/**
 * Classify an explicit update target. Dist-tags resolve to one concrete version;
 * ranges, aliases, unknown tags, and registry failures fail closed.
 */
export declare function resolveExplicitNpmUpdateTarget(target: string, allowPrerelease: boolean, loadDistTags?: NpmDistTagsLoader): Promise<ExplicitNpmUpdateTargetDecision>;
/** Pure channel/default selection over one already-decoded registry response. */
export declare function selectNpmVersionTarget(result: NpmDistTagsResult, allowPrerelease?: boolean, channel?: string): NpmVersionResolution;
/** Select the version followed by automatic polling or an explicit channel pin. */
export declare function resolveNpmVersionTarget(allowPrerelease?: boolean, channel?: string, loadDistTags?: NpmDistTagsLoader): Promise<NpmVersionResolution>;
export declare function compareSemver(a: string, b: string): number;
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