Cmake 似乎没有使用它确认使用的 Python 解释器

Question

我有以下 CMakeLists.txt 文件，指示使用 Python 4.4

cmake_minimum_required(VERSION 3.2 FATAL_ERROR)
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/../cmake/")

project(aConfigd VERSION 1.0)
string(TOLOWER aConfigd project_id)

find_package(PythonInterp 3.4 REQUIRED)

include(FindPythonInterp)
set(PYTHON ${PYTHON_EXECUTABLE})
message(STATUS "\${PYTHON_EXECUTABLE} == ${PYTHON_EXECUTABLE}")
set(pkgdatadir /usr/share/configd)
set(configdir /etc/amy)
set(SONARCONFIGID_SOURCE_DIR etc/configd)
set(SRC_DIR configd/src/)

include(common)
#        "${SRC_DIR}/systemd_client.py"
#        "${SRC_DIR}/amyconfig_service.py"
        "${SRC_DIR}/__init__.py"
        "${SRC_DIR}/main.py"
        "${SRC_DIR}/application.py"
        DESTINATION ${pkgdatadir}/configd/
)

#general
set(CPACK_PACKAGE_NAME "a-config")
set(CPACK_PACKAGE_DESCRIPTION_SUMMARY "a-config-manager")
set(CPACK_PACKAGE_DESCRIPTION "a-config-manager")

# redhat
set(CPACK_RPM_EXCLUDE_FROM_AUTO_FILELIST_ADDITION 
      /etc/amy
      )

include(cpack)

确实，它确认了${PYTHON_EXECUTABLE} == /usr/bin/python3.4（见下面的第 4 行）：

$ make clean ; cmake -DCMAKE_BUILD_TYPE=Release -DSHORT_VERSION=NO -DCUSTOMER=NO .. ;  make -j12 ; make package
-- Found PythonInterp: /usr/bin/python3.4 (found suitable version "3.4.5", minimum required is "3.4") 
-- Found PythonInterp: /usr/bin/python3.4 (found version "3.4.5") 
-- ${PYTHON_EXECUTABLE} == /usr/bin/python3.4
-- Build Type: Release
-- Detected distribution: rhel fedora
-- Detected aConfigd version: 2.3.0-3030-gf7733cf659
-- Detected distribution: rhel fedora
-- Configuring done
-- Generating done
-- Build files have been written to: /local/raid0/git/amy/aConfig/build
Run CPack packaging tool...
CPack: Create package using RPM
CPack: Install projects
CPack: - Run preinstall target for: aConfigd
CPack: - Install project: aConfigd
CPack: Create package
CPackRPM:Warning: CPACK_SET_DESTDIR is set (=ON) while requesting a relocatable package (CPACK_RPM_PACKAGE_RELOCATABLE is set): this is not supported, the package won't be relocatable.
CPackRPM: Will use GENERATED spec file: /local/raid0/git/my/aConfig/build/_CPack_Packages/Linux/RPM/SPECS/a-config.spec
CPack: - package: /local/raid0/git/my/aConfig/build/a-config-2.3.0-3030-gf7733cf659.el7.my.x86_64.rpm generated.
$ 

但是，如果我取消注释 "${SRC_DIR}/systemd_client.py" 行，我会收到错误：

Compiling /local/raid0/git/my/aConfig/build/_CPack_Packages/Linux/RPM/a-config-2.3.0-3030-gf7733cf659.el7.my.x86_64/usr/share/configd/configd/systemd_client.py ...
  File "/usr/share/configd/configd/systemd_client.py", line 21
    def __init__(self, systemd_proxy:Gio.DBusProxy):
                                    ^
SyntaxError: invalid syntax

def __init__(self, systemd_proxy:Gio.DBusProxy): a valid Python 3.4 不是语法吗？
如果是，为什么 Cmake 会抱怨？

Answer 1

根本原因出现在 rpmbuild 步骤中。
RPM 试图提供额外的帮助，并尝试（字节码）编译它遇到的 .py 文件。
唉，它错误地使用 python2 解释器来创建文件的字节码（即使在 CMakeLists.txt 文件中声明了find_package(PythonInterp 3.4 REQUIRED)）。

对我有用的解决方法是：

set(CPACK_RPM_BUILDREQUIRES python34-devel)
set(CPACK_RPM_SPEC_MORE_DEFINE "%define __python ${PYTHON_EXECUTABLE}")

Answer 2

当您只运行"${SRC_DIR}/systemd_client.py" 时，您是在告诉它以与shell 运行相同的方式运行该脚本：查看#! 行并使用那里指定的任何解释器运行它。这可能类似于#! /usr/bin/python 或#! /usr/bin/env python。

如果您想使用特定的解释器运行脚本，则必须运行该解释器并将脚本传递给它——就像在 shell 中一样。我对 CMake 很生疏，但我假设你会这样做：

"${PYTHON_EXECUTABLE}" "${SRC_DIR}/amyconfig_service.py"

或者，由于这是您的代码，也许您想使用 setuptools 以编程方式为您的入口点生成脚本，这意味着它将为它们创建一个 #! 行，以运行用于运行的任何 Python 版本setup.py.