Function applyHunks

src/apply-patch.ts:249–284

(path: string, content: string, hunks: UpdateHunk[])

}

function applyHunks(path: string, content: string, hunks: UpdateHunk[]): string {
  const file = splitFile(content);
  const lines = [...file.lines];
  let cursor = 0;

  for (const hunk of hunks) {
    if (hunk.changeContext) {
      const contextIndex = findSequence(lines, [hunk.changeContext], cursor);
      if (contextIndex < 0) {
        throw patchError(`could not find hunk context in ${path}: ${hunk.changeContext}`);
      }
      cursor = contextIndex + 1;
    }

    const oldLines = hunk.lines
      .filter((line) => line.kind !== "add")
      .map((line) => line.text);
    const newLines = hunk.lines
      .filter((line) => line.kind !== "remove")
      .map((line) => line.text);
    const index = hunk.endOfFile && oldLines.length === 0
      ? lines.length
      : findSequence(lines, oldLines, cursor, hunk.endOfFile);

    if (index < 0) {
      const preview = oldLines.slice(0, 3).join("\n");
      throw patchError(`could not find hunk context in ${path}: ${preview}`);
    }

    lines.splice(index, oldLines.length, ...newLines);
    cursor = index + newLines.length;
  }

  const normalized = `${lines.join("\n")}\n`;
  return file.eol === "\r\n" ? normalized.replace(/\n/g, "\r\n") : normalized;
}

async function fileExists(path: string): Promise<boolean> {
  try {