[Scons-users] solving dependency cycle

[Chris BeHanna]

On Aug 17, 2012, at 05:21 , Kraus Philipp <philipp.kraus at flashpixx.de> wrote:


> Hello,

> 

> how can I solve "dependency cycles" ?

> 

> I have got 3 source files (a, b c) that creates one target

> finally = env.Program( ..., sources=[a,b,c] )

> 

> I have got a previous target x on which a, b and c depends:

> 

> finally depends on a, b, c

> a depends on x

> b depends also on x

> c depends also on x

> 

> Scons creates the error, that it detects a dependy cycle. There is one, because

> three targets depend on one. How can I solve this problem?

> I try to use "SideEffect", so that only one of the targets builds x, but the cycle exists also

> and Scons create an error. Can I tell scons, that it use only one branch of the graph to build x

> and ignores the other one?


	Typically, to break such cycles, you have to refactor your code.  This is sometimes nontrivial.  Note that what you have described, however, is not a cycle:

	a -> x
	b -> x
	c -> x

is not a cycle unless x also depends upon one of a, b, or c.

-- 
Chris BeHanna
chris at behanna.org