7e3465f63a
The boolean 'choice' is used to list exclusively selected config
options.
You must not add a dependency between choice members, because such a
dependency would create an invisible entry.
In the following test case, it is impossible to choose 'C'.
[Test Case 1]
choice
prompt "Choose one, but how to choose C?"
config A
bool "A"
config B
bool "B"
config C
bool "C"
depends on A
endchoice
Hence, Kconfig shows the following error message:
Kconfig:1:error: recursive dependency detected!
Kconfig:1: choice <choice> contains symbol C
Kconfig:10: symbol C is part of choice A
Kconfig:4: symbol A is part of choice <choice>
For a resolution refer to Documentation/kbuild/kconfig-language.rst
subsection "Kconfig recursive dependency limitations"
However, Kconfig does not report anything for the following similar code:
[Test Case 2]
choice
prompt "Choose one, but how to choose B?"
config A
bool "A"
config B
bool "B"
depends on A
config C
bool "C"
endchoice
This is because menu_finalize() reparents the menu tree when an entry
depends on the preceding one.
With reparenting, the menu tree:
choice
|- A
|- B
\- C
... will be transformed into the following structure:
choice
|- A
| \- B
\- C
Consequently, Kconfig considers only 'A' and 'C' as choice members.
This behavior is awkward. The second test case should be an error too.
This commit stops reparenting inside a choice.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.