Function parseVariablesArg

packages/cli/src/utils/variables.ts:47–94

(
  inline: string | undefined,
  filePath: string | undefined,
  readFile: (path: string) => string = (p) => readFileSync(resolve(p), "utf8"),
)

// type-discriminated parser whose value is exactly testability.
// fallow-ignore-next-line unused-export complexity
export function parseVariablesArg(
  inline: string | undefined,
  filePath: string | undefined,
  readFile: (path: string) => string = (p) => readFileSync(resolve(p), "utf8"),
): VariablesParseResult {
  if (inline != null && filePath != null) {
    return { ok: false, error: { kind: "conflict" } };
  }
  let raw: string | undefined;
  let source: "inline" | "file" | undefined;
  if (inline != null) {
    raw = inline;
    source = "inline";
  } else if (filePath != null) {
    try {
      raw = readFile(filePath);
      source = "file";
    } catch (error: unknown) {
      return {
        ok: false,
        error: {
          kind: "read-error",
          path: filePath,
          cause: error instanceof Error ? error.message : String(error),
        },
      };
    }
  }
  if (raw == null) return { ok: true, value: undefined };

  let parsed: unknown;
  try {
    parsed = JSON.parse(raw);
  } catch (error: unknown) {
    return {
      ok: false,
      error: {
        kind: "parse-error",
        source: source ?? "inline",
        cause: error instanceof Error ? error.message : String(error),
      },
    };
  }
  if (parsed == null || typeof parsed !== "object" || Array.isArray(parsed)) {
    return { ok: false, error: { kind: "shape-error" } };
  }
  return { ok: true, value: parsed as Record<string, unknown> };
}

function variablesErrorMessage(error: VariablesParseError): { title: string; message: string } {
  switch (error.kind) {