chromium - gn 脚本使用错误的 Python 版本 ("a bytes-like object is required, not ' str'")

Question

使用 gn 构建 Chromium 或 libwebrtc 时在 macOS (Catalina 10.15) 上，我从 Python 构建脚本中收到关于 bytes 的错误和 str .例如:

src [heads/master●] % gn gen out/ios_64 --args='target_os="ios" target_cpu="arm64"'
ERROR at //build/config/ios/ios_sdk.gni:109:21: Script returned non-zero exit code.
  _ios_sdk_result = exec_script(script_name, ios_sdk_info_args, "scope")
                    ^----------
Current dir: /Users/lynn/code/webrtc_ios/src/out/ios_64/
Command: python /Users/lynn/code/webrtc_ios/src/build/config/mac/sdk_info.py --get_sdk_info iphoneos
Returned 1.
stderr:

Traceback (most recent call last):
  File "/Users/lynn/code/webrtc_ios/src/build/config/mac/sdk_info.py", line 107, in <module>
    FillXcodeVersion(settings, args.developer_dir)
  File "/Users/lynn/code/webrtc_ios/src/build/config/mac/sdk_info.py", line 59, in FillXcodeVersion
    settings['xcode_version'] = FormatVersion(lines[0].split()[-1])
  File "/Users/lynn/code/webrtc_ios/src/build/config/mac/sdk_info.py", line 43, in FormatVersion
    major, minor, patch = SplitVersion(version)
  File "/Users/lynn/code/webrtc_ios/src/build/config/mac/sdk_info.py", line 30, in SplitVersion
    version = version.split('.')
TypeError: a bytes-like object is required, not 'str'

See //build/config/sysroot.gni:67:3: whence it was imported.
  import("//build/config/ios/ios_sdk.gni")
  ^--------------------------------------
See //build/config/linux/pkg_config.gni:5:1: whence it was imported.
import("//build/config/sysroot.gni")
^----------------------------------
See //BUILD.gn:15:1: whence it was imported.
import("//build/config/linux/pkg_config.gni")
^-------------------------------------------

当我将有问题的 Python 脚本编辑为 print(sys.version) 时，它表明它正在运行 Python 3，即使脚本应该在 .vpython 中定义的捆绑虚拟 Python 2.7 环境中运行。 .

如何配置 gn使用适当的 Python 版本运行这些脚本？

Answer 1

好像exec_script正在使用机器 Python 版本运行这些脚本。 gn help exec_script说:

The default script interpreter is Python ("python" on POSIX, "python.exe" or "python.bat" on Windows). This can be configured by the script_executable variable, see "gn help dotfile".

对我来说，python指向 Python 3。所以我不得不将这一行添加到 .gn dotfile 的末尾:

script_executable = "vpython"

现在构建使用在 .vpython 中定义的虚拟 Python。 ，这是 Python 2.7。

(vpython 可执行文件由 Chromium depot_tools 提供，就像 gn 一样。)