Uncaught AssertionError in diffs.py line 40

[LuciusChen]

Aider version: 0.59.1
Python version: 3.12.7
Platform: macOS-15.0.1-arm64-arm-64bit
Python implementation: CPython
Virtual environment: Yes
OS: Darwin 24.0.0 (64bit)
Git version: git version 2.39.5 (Apple Git-154)

An uncaught exception occurred:

Traceback (most recent call last):
  File "aider", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "main.py", line 757, in main
    coder.run()
  File "base_coder.py", line 730, in run
    self.run_one(user_message, preproc)
  File "base_coder.py", line 773, in run_one
    list(self.send_message(message))
  File "base_coder.py", line 1170, in send_message
    self.live_incremental_response(True)
  File "base_coder.py", line 1535, in live_incremental_response
    show_resp = self.render_incremental_response(final)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "wholefile_coder.py", line 18, in render_incremental_response
    return self.get_edits(mode="diff")
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "wholefile_coder.py", line 102, in get_edits
    output += self.do_live_diff(full_path, new_lines, False)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "wholefile_coder.py", line 136, in do_live_diff
    show_diff = diffs.diff_partial_update(
                ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "diffs.py", line 53, in diff_partial_update
    assert_newlines(lines_orig)
  File "diffs.py", line 40, in assert_newlines
    assert line and line[-1] == "\n", line
           ^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: