A small python script that updates the timestamp on a file to match that in the directory state file.

fix.py

#! /usr/bin/env python
"""
usage: fix.py [-h] path

mitigate mercurial bug 6528 for a particular repo

positional arguments:
  path        the path of the affected repo

optional arguments:
  -h, --help  show this help message and exit
"""

import argparse
import os
import pathlib

from mercurial.pure.parsers import parse_dirstate

parser = argparse.ArgumentParser(
    description="mitigate mercurial bug 6528 for a particular repo"
)
parser.add_argument("path", help="the path of the affected repo")

# Path of misbehaving file.
path = b"toolkit/themes/shared/icons/reload.svg"

if __name__ == "__main__":
    _map = dict()
    args = parser.parse_args()
    base_path = pathlib.Path(args.path)
    with open(base_path / ".hg" / "dirstate", "rb") as f:
        # Read directory state file.
        dirstate = f.read()

        # Parse directory state into `_map`.
        parse_dirstate(_map, {}, dirstate)

        # Fetch the timestamp in directory state, then modify the file on disk to match.
        timestamp = _map[path][-1]
        misbehaving_path = base_path / path.decode("utf-8")
        os.utime(misbehaving_path, (timestamp, timestamp))
        print("Updated timestamp to {} for {}.".format(timestamp, misbehaving_path))