"AttributeError: 'xml.etree.ElementTree.Element' object has no attribute 'getchildren'" on Subversion working copy

I'm getting an error every time I run meld . in a Subversion working copy.

Traceback (most recent call last):
  File "/usr/lib/python3.9/site-packages/meld/task.py", line 110, in iteration
    ret = task()
  File "/usr/lib/python3.9/site-packages/meld/vc/_vc.py", line 277, in refresh_vc_state
    self._update_tree_state_cache(path)
  File "/usr/lib/python3.9/site-packages/meld/vc/svn.py", line 188, in _update_tree_state_cache
    for entry in (t for t in target.getchildren() if t.tag == "entry"):
AttributeError: 'xml.etree.ElementTree.Element' object has no attribute 'getchildren'

The Meld window shows only the directory name, no files are listed, even though svn status -q shows there are files that should be listed.

This only happens with Subversion; running meld . in a Git repository works fine.

This used to work, although I don't remember exactly when it stopped working. I don't think it was after a Meld upgrade; I probably upgraded something else and it broke Meld. This is on Arch Linux with all packages up-to-date as of today.

I have Meld 3.20.2, svn version 1.14.0 (r1876290) compiled Nov 12 2020, 14:38:24 on x86_64-pc-linux-gnu, and Python 3.9.1.