xref: /linux/Documentation/kbuild/Kconfig.select-break (revision 2697b79a469b68e3ad3640f55284359c1396278d)
1# Select broken dependency issue
2# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3#
4# Test with:
5#
6# make KBUILD_KCONFIG=Documentation/kbuild/Kconfig.select-break menuconfig
7#
8# kconfig will not complain and enable this layout for configuration. This is
9# currently a feature of kconfig, given select was designed to be heavy handed.
10# Kconfig currently does not check the list of symbols listed on a symbol's
11# "select" list, this is done on purpose to help load a set of known required
12# symbols. Because of this use of select should be used with caution. An
13# example of this issue is below.
14#
15# The option B and C are clearly contradicting with respect to A.
16# However, when A is set, C can be set as well because Kconfig does not
17# visit the dependencies of the select target (in this case B).  And since
18# Kconfig does not visit the dependencies, it breaks the dependencies of B
19# (!A).
20
21mainmenu "Simple example to demo kconfig select broken dependency issue"
22
23config A
24	bool "CONFIG A"
25
26config B
27	bool "CONFIG B"
28	depends on !A
29
30config C
31	bool "CONFIG C"
32	depends on A
33	select B
34