/**
 * Compute the set of source files that have changed since the graph was built.
 *
 * Two paths:
 *
 *  1. `--since <git-ref>` (CI-friendly) — `git diff --name-only <ref>...HEAD`
 *     plus uncommitted modifications. The merge-base form is intentional:
 *     it captures every file the PR touched, not just the latest commit.
 *
 *  2. No `--since` flag — fall back to comparing file mtimes against
 *     `fingerprint.json.computedAt`. Slower but works without git history.
 *
 * Either path returns paths relative to the repo root. Non-source files
 * (anything not tracked by the analyzer's language config) are filtered out
 * by the caller via the node table.
 */
export interface DiffResult {
    /** Repo-relative paths of files that may have changed since graph build. */
    changed: string[];
    /** Which mechanism produced the list. */
    mechanism: 'git' | 'mtime';
    /** Any non-fatal warnings (e.g. "no .git found, used mtime"). */
    warnings: string[];
    /** The short commit hash of HEAD at the moment of the check, if available. */
    workingCommit: string | null;
}
export interface DiffOptions {
    repoRoot: string;
    /** Iso8601 timestamp the graph was built — used by mtime fallback. */
    graphBuiltAt: string | null;
    /** Optional git ref to diff against (e.g. "origin/main"). */
    since?: string;
}
export declare function hasGitDirectory(repoRoot: string): Promise<boolean>;
export declare function refExists(repoRoot: string, ref: string): Promise<boolean>;
export declare function computeDiff(opts: DiffOptions): Promise<DiffResult>;
/** Read `fingerprint.json` if present. */
export declare function readGraphFingerprint(repoRoot: string): Promise<{
    computedAt: string | null;
    fileCount: number | null;
} | null>;
//# sourceMappingURL=diff.d.ts.map