deepseek-ai/deepseek-harness · error · Error

old_string must be a non-empty string

Error message

old_string must be a non-empty string

What it means

Error "old_string must be a non-empty string" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/fs/tool-fs/src/edit.ts:49

interface EditToolArgs {
  file_path: string
  old_string: string
  new_string: string
  replace_all?: boolean
  sandbox_permissions?: string
  justification?: string
}

/**
 * Validate value constraints the schema DSL can't express: a non-blank
 * `file_path`, a non-empty `old_string`, and `old_string !== new_string`
 * (an equal pair would be a guaranteed no-op edit).
 * @param args - the schema-validated raw tool arguments.
 * @returns the camelCased input with `replace_all` defaulted to false.
 */
export function parseEditArgs(args: { file_path: string; old_string: string; new_string: string; replace_all?: boolean }): EditInput {
  if (args.file_path.trim().length === 0) throw new Error('file_path must be a non-empty string')
  if (args.old_string.length === 0) throw new Error('old_string must be a non-empty string')
  if (args.old_string === args.new_string) throw new Error('old_string and new_string must differ')
  return {
    filePath: args.file_path,
    oldString: args.old_string,
    newString: args.new_string,
    replaceAll: args.replace_all ?? false,
  }
}

/**
 * Format an edit success (single-match or replace-all) as a Claude-style model-facing message.
 * @param displayPath - the backend-resolved path shown to the model.
 * @param replaceAll - selects the all-occurrences wording over the single-replacement one.
 * @returns the confirmation sentence the model sees as the tool result.
 */
export function formatEditOutput(displayPath: string, replaceAll: boolean): string {
  return replaceAll
    ? `The file ${displayPath} has been updated. All occurrences were successfully replaced.`

View on GitHub (pinned to b150a551b8)

When it happens

Trigger: Thrown at packages/fs/tool-fs/src/edit.ts:49 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of deepseek-ai/deepseek-harness@b150a551b8 (2026-08-24). Data as JSON: /api/errors/91b1224f95692b7a. Report an issue: GitHub.