Function replace

packages/opencode/src/tool/edit.ts:682–729

(content: string, oldString: string, newString: string, replaceAll = false)

}

export function replace(content: string, oldString: string, newString: string, replaceAll = false): string {
  if (oldString === newString) {
    throw new Error("No changes to apply: oldString and newString are identical.")
  }
  if (oldString === "") {
    throw new Error(
      "oldString cannot be empty when editing an existing file. Provide the exact text to replace, or use write for an intentional full-file replacement.",
    )
  }

  let notFound = true

  for (const replacer of [
    SimpleReplacer,
    LineTrimmedReplacer,
    BlockAnchorReplacer,
    WhitespaceNormalizedReplacer,
    IndentationFlexibleReplacer,
    EscapeNormalizedReplacer,
    TrimmedBoundaryReplacer,
    ContextAwareReplacer,
    MultiOccurrenceReplacer,
  ]) {
    for (const search of replacer(content, oldString)) {
      const index = content.indexOf(search)
      if (index === -1) continue
      notFound = false
      if (isDisproportionateMatch(search, oldString)) {
        throw new Error(
          "Refusing replacement because the matched span is much larger than oldString. Re-read the file and provide the full exact oldString for the intended replacement.",
        )
      }
      if (replaceAll) {
        return content.replaceAll(search, newString)
      }
      const lastIndex = content.lastIndexOf(search)
      if (index !== lastIndex) continue
      return content.substring(0, index) + newString + content.substring(index + search.length)
    }
  }

  if (notFound) {
    throw new Error(
      "Could not find oldString in the file. It must match exactly, including whitespace, indentation, and line endings.",
    )
  }
  throw new Error("Found multiple matches for oldString. Provide more surrounding context to make the match unique.")
}

function isDisproportionateMatch(search: string, oldString: string) {
  const oldLines = oldString.split("\n").length