SCons:依赖循环？

Question

我试图让 SCons 将 Makefile 项目从源目录复制到构建目录并运行一些命令来生成 libmoo.a，但我遇到了依赖循环错误。详情如下:

./S构造:

env = Environment()
Export('env')

dirs = ['.']

variant_dir = 'build'

for dir in dirs:
        SConscript(dir + '/' + 'SConscript', variant_dir=variant_dir + '/' + dir, duplicate=0)

./SConscript:

import os
Import('env')

env.Command(env.Dir('moo2').abspath, env.Dir('#moo').abspath, ["echo copying moo to the build dir", Copy("$TARGET", "$SOURCE")])

env.Command(env.Dir('moo2/Makefile').abspath, env.Dir('moo2').abspath, 'echo would run moo2.configure')

moolib = env.Command(env.Dir('moo2/libmoo.a').abspath, env.Dir('moo2/Makefile').abspath, 'echo would run make')

Default(moolib)

运行 scons 时出错:

scons: *** Found dependency cycle(s):
  build/moo2/Makefile -> build/moo2 -> build/moo2/Makefile
  build/moo2/libmoo.a -> build/moo2 -> build/moo2/Makefile -> build/moo2/libmoo.a

也试过不使用 .abspath，但这应该没关系，对吧？

我没有看到任何循环:

build/moo2/libmoo.a 需要 build/moo2/Makefile

build/moo2/Makefile 需要 build/moo2

build/moo2 需要 (source/)moo

scons 如何看待循环？似乎认为build/moo2/Makefile依赖于build/moo2/libmoo.a，这不是我想指定的。

也欢迎任何相关建议:-)

Answer 1

SConscript 中的任何地方都不需要 env.Dir('moo').abspath。所以这会将其更改为:

Import('env')
env.Command('moo2', '#moo', ["echo copying moo to the build dir", Copy("$TARGET", "$SOURCE")])
env.Command('moo2/Makefile', 'moo2', 'echo would run moo2.configure')  # Look Here
moolib = env.Command('moo2/libmoo.a', 'moo2/Makefile', 'echo would run make')
Default(moolib)

但这仍然会产生相同的错误:

scons: *** Found dependency cycle(s):
build/moo2/Makefile -> build/moo2 -> build/moo2/Makefile
build/moo2/libmoo.a -> build/moo2/Makefile -> build/moo2/libmoo.a

那是为什么？
SCons 自动使目录依赖于其中包含的所有文件。
请参阅带有“# Look Here”注释的行。您已经添加了依赖项 moo2/Makefile 现在依赖于 moo2。默认情况下，moo2 取决于它的所有内容，因此取决于您的周期。

那么我们该如何修复呢？

Import('env')
env.Install('moo2',Glob('#moo/*'))
env.Command('moo2/Makefile', env.Glob('moo2/*'), 'echo would run moo2.configure')
moolib = env.Command('moo2/libmoo.a', 'moo2/Makefile', 'echo would run make')
Default(moolib)

我已经从使用 Copy() 更改为 env.Install()。由于 Copy 未附加到构建 Environment() 对象，因此它不会知道变体目录。 Install() 和 Copy() 在功能上是等效的， env.Install() 是 env 感知的。
另外我有它复制/依赖于目录中的所有文件，而不是目录本身。

现在让我们试一试:

/opt/local/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python /Users/bdbaddog/devel/scons/trunk/bootstrap/src/script/scons.py --tree=prune
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...
Install file: "moo/abc.c" as "build/moo2/abc.c"
Install file: "moo/configure" as "build/moo2/configure"
Install file: "moo/def.c" as "build/moo2/def.c"
echo would run moo2.configure
would run moo2.configure
echo would run make
would run make
+-build/moo2/libmoo.a
  +-build/moo2/Makefile
  | +-build/moo2/abc.c
  | | +-moo/abc.c
  | +-build/moo2/configure
  | | +-moo/configure
  | +-build/moo2/def.c
  | | +-moo/def.c
  | +-/bin/echo
  +-/bin/echo
scons: done building targets.

注意“--tree=prune”这个标志会让 SCons 打印出依赖树并修剪树中的重复(所以如果 2 个文件依赖于同一个文件树，你只会看到一次)