PyQt6调用QFontDatabase.addApplicationFont触发0xC0000005错误求助

问题背景 #

使用PyQt6 6.5.2编写代码时，执行字体加载逻辑会导致程序崩溃，退出码为-1073741819 (0xC0000005)，注释掉字体加载的前两行代码后程序可正常运行。

原始代码片段：

self.font_id = QFontDatabase.addApplicationFont('conf/font.otf')
self.font_family = QFontDatabase.applicationFontFamilies(font_id)

for name, classtype in self.__dict__.items():
    try:
        classtype.setFont(QFont(self.font_family[0], int(self.base_cfg['Config']['fontSize']), QFont.Weight.Bold))
    except AttributeError:
        pass

最小复现代码 #

仅执行以下两行代码就会触发崩溃：

from PyQt6.QtGui import QFontDatabase
QFontDatabase.addApplicationFont('conf/font.otf')

环境信息 #

• Python版本：3.9.4 / 3.10.2 / 3.11.4
• 操作系统：Windows 11 版本22621.2070
• PyQt6版本：6.5.2

调试报错信息 #

在PyCharm运行配置中添加-X dev解释器选项后，得到以下访问违规报错：

Windows fatal exception: access violation

Thread 0x00002a00 (most recent call first):
  File "D:\Software\PyCharm Community Edition 2023.2\plugins\python-ce\helpers\pydev\pydevd.py", line 138 in _on_run
  File "D:\Software\PyCharm Community Edition 2023.2\plugins\python-ce\helpers\pydev\_pydevd_bundle\pydevd_comm.py", line 219 in run
  File "D:\Software\Python\lib\threading.py", line 1009 in _bootstrap_inner
  File "D:\Software\Python\lib\threading.py", line 966 in _bootstrap

Thread 0x00004cd4 (most recent call first):
  File "D:\Software\PyCharm Community Edition 2023.2\plugins\python-ce\helpers\pydev\_pydevd_bundle\pydevd_comm.py", line 293 in _on_run
  File "D:\Software\PyCharm Community Edition 2023.2\plugins\python-ce\helpers\pydev\_pydevd_bundle\pydevd_comm.py", line 219 in run
  File "D:\Software\Python\lib\threading.py", line 1009 in _bootstrap_inner
  File "D:\Software\Python\lib\threading.py", line 966 in _bootstrap

Thread 0x00004728 (most recent call first):
  File "D:\Software\Python\lib\threading.py", line 324 in wait
  File "D:\Software\Python\lib\queue.py", line 180 in get
  File "D:\Software\PyCharm Community Edition 2023.2\plugins\python-ce\helpers\pydev\_pydevd_bundle\pydevd_comm.py", line 368 in _on_run
  File "D:\Software\PyCharm Community Edition 2023.2\plugins\python-ce\helpers\pydev\_pydevd_bundle\pydevd_comm.py", line 219 in run
  File "D:\Software\Python\lib\threading.py", line 1009 in _bootstrap_inner
  File "D:\Software\Python\lib\threading.py", line 966 in _bootstrap

排查与解决建议 #

• 检查字体文件完整性：
  字体文件损坏或格式不兼容是常见触发原因，替换为已知可用的OTF字体测试，或重新导出当前字体文件确保无损坏。
• 使用绝对路径加载字体：
  相对路径可能因工作目录问题导致Qt无法找到文件，改用绝对路径：

  import os
  font_path = os.path.abspath(os.path.join(os.path.dirname(__file__), 'conf/font.otf'))
  QFontDatabase.addApplicationFont(font_path)
  

• 验证字体格式兼容性：
  部分OTF字体包含Qt无法处理的特殊结构，用FontForge等工具打开并重新导出为标准OTF格式后再测试。
• 调整PyQt6版本：
  6.5.2版本可能存在Windows平台字体加载bug，尝试降级到6.5.1或升级至最新稳定版：

  pip uninstall pyqt6 -y
  pip install pyqt6==6.5.1
  

• 排除IDE调试干扰：
  在纯命令行下运行最小复现代码，确认是否是PyCharm调试工具导致的冲突：

  python your_script.py
  

• 修复Qt运行环境：
  卸载并重新安装PyQt6，确保依赖的Qt运行库完整无损坏。

内容的提问来源于stack exchange，提问作者Yukari_Shiina