import type { TemplateSourceInfo } from "../ir/ir.js";
import type { Column } from "./schema.js";
import type { SchemaProvider } from "./schema-provider.js";
import type { TemplateProvider } from "./template-provider.js";
/** The schema as a TemplateProvider when it is one (structural — the shipped base or a subclass). */
export declare function asProvider(schema: SchemaProvider): TemplateProvider | undefined;
/**
 * Resolve a templated source's TYPED columns through the provider, or undefined for the
 * exemption (no call, no provider, no relation answer). A relation answer WITHOUT columns
 * (`columns: undefined` — the not-loaded sentinel) resolves through the physical-name
 * lookup; `columns: []` is a genuinely EMPTY relation.
 */
export declare function relationColumns(t: TemplateSourceInfo, schema: SchemaProvider, dialect?: string): Column[] | undefined;
/**
 * TYPED columns of a table source, template-aware: a templated source resolves through
 * the provider first (real warehouse columns); no answer — or no provider — falls back
 * to the plain `columnsFor(name)` lookup (which for a templated source carries the
 * dbt-logical name, so a Schema declaring model names keeps answering as before).
 */
export declare function tableSourceColumns(name: string[], template: TemplateSourceInfo | undefined, schema: SchemaProvider, dialect?: string): Column[] | undefined;