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5e8c5299d3
Currently, Kconfig does not complain about the recursive dependency
where 'imply' keywords are involved.
[Test Code]
config A
bool "a"
config B
bool "b"
imply A
depends on A
In the code above, Kconfig cannot calculate the symbol values correctly
due to the circular dependency. For example, allyesconfig followed by
syncconfig results in an odd behavior because CONFIG_B becomes visible
in syncconfig.
$ make allyesconfig
scripts/kconfig/conf --allyesconfig Kconfig
#
# configuration written to .config
#
$ cat .config
#
# Automatically generated file; DO NOT EDIT.
# Main menu
#
CONFIG_A=y
$ make syncconfig
scripts/kconfig/conf --syncconfig Kconfig
*
* Restart config...
*
*
* Main menu
*
a (A) [Y/n/?] y
b (B) [N/y/?] (NEW)
To detect this correctly, sym_check_expr_deps() should recurse to
not only sym->rev_dep.expr but also sym->implied.expr .
At this moment, sym_check_print_recursive() cannot distinguish
'select' and 'imply' since it does not know the precise context
where the recursive dependency has been hit. This will be solved
by the next commit.
In fact, even the document and the unit-test are confused. Using
'imply' does not solve recursive dependency since 'imply' addresses
the unmet direct dependency, which 'select' could cause.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Dirk Gouders <dirk@gouders.net>
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 Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
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.