expr_trans_bool() performs an incorrect transformation.

[Test Code]

    config MODULES
            def_bool y
            modules

    config A
            def_bool y
            select C if B != n

    config B
            def_tristate m

    config C
            tristate

[Result]

    CONFIG_MODULES=y
    CONFIG_A=y
    CONFIG_B=m
    CONFIG_C=m

This output is incorrect because CONFIG_C=y is expected.

Documentation/kbuild/kconfig-language.rst clearly explains the function
of the '!=' operator:

    If the values of both symbols are equal, it returns 'n',
    otherwise 'y'.

Therefore, the statement:

    select C if B != n

should be equivalent to:

    select C if y

Or, more simply:

    select C

Hence, the symbol C should be selected by the value of A, which is 'y'.

However, expr_trans_bool() wrongly transforms it to:

    select C if B

Therefore, the symbol C is selected by (A && B), which is 'm'.

The comment block of expr_trans_bool() correctly explains its intention:

  * bool FOO!=n => FOO
    ^^^^

If FOO is bool, FOO!=n can be simplified into FOO. This is correct.

However, the actual code performs this transformation when FOO is
tristate:

    if (e->left.sym->type == S_TRISTATE) {
                             ^^^^^^^^^^

While it can be fixed to S_BOOLEAN, there is no point in doing so
because expr_tranform() already transforms FOO!=n to FOO when FOO is
bool. (see the "case E_UNEQUAL" part)

expr_trans_bool() is wrong and unnecessary.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>

Currently, the initial state of the "Save" button is always active.

If none of the CONFIG options are changed while loading the .config
file, the "Save" button should be greyed out.

This can be fixed by calling conf_read() after widget initialization.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This is a leftover from commit ce1fc9345a59 ("kconfig: do not clear
SYMBOL_DEF_USER when the value is out of range").

This code is now redundant because if a user-supplied value is out
of range, the value adjusted by sym_validate_range() differs, and
conf_unsaved has already been incremented a few lines above.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The check for 'sym1 == sym2' is redundant here because it has already
been done a few lines above:

    if (sym1 != sym2)
            return NULL;

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Currently, comparisons to 'm' or 'n' result in incorrect output.

[Test Code]

    config MODULES
            def_bool y
            modules

    config A
            def_tristate m

    config B
            def_bool A > n

CONFIG_B is unset, while CONFIG_B=y is expected.

The reason for the issue is because Kconfig compares the tristate values
as strings.

Currently, the .type fields in the constant symbol definitions,
symbol_{yes,mod,no} are unspecified, i.e., S_UNKNOWN.

When expr_calc_value() evaluates 'A > n', it checks the types of 'A' and
'n' to determine how to compare them.

The left-hand side, 'A', is a tristate symbol with a value of 'm', which
corresponds to a numeric value of 1. (Internally, 'y', 'm', and 'n' are
represented as 2, 1, and 0, respectively.)

The right-hand side, 'n', has an unknown type, so it is treated as the
string "n" during the comparison.

expr_calc_value() compares two values numerically only when both can
have numeric values. Otherwise, they are compared as strings.

    symbol    numeric value    ASCII code
    -------------------------------------
      y           2             0x79
      m           1             0x6d
      n           0             0x6e

'm' is greater than 'n' if compared numerically (since 1 is greater
than 0), but smaller than 'n' if compared as strings (since the ASCII
code 0x6d is smaller than 0x6e).

Specifying .type=S_TRISTATE for symbol_{yes,mod,no} fixes the above
test code.

Doing so, however, would cause a regression to the following test code.

[Test Code 2]

    config MODULES
            def_bool n
            modules

    config A
            def_tristate n

    config B
            def_bool A = m

You would get CONFIG_B=y, while CONFIG_B should not be set.

The reason is because sym_get_string_value() turns 'm' into 'n' when the
module feature is disabled. Consequently, expr_calc_value() evaluates
'A = n' instead of 'A = m'. This oddity has been hidden because the type
of 'm' was previously S_UNKNOWN instead of S_TRISTATE.

sym_get_string_value() should not tweak the string because the tristate
value has already been correctly calculated. There is no reason to
return the string "n" where its tristate value is mod.

Fixes: 31847b67bec0 ("kconfig: allow use of relations other than (in)equality")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This has not been used since commit e911503085ae ("Kconfig: Remove
bad inference rules expr_eliminate_dups2()").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Choices and their members are associated via the P_CHOICE property.

Currently, prop_get_symbol(sym_get_choice_prop()) is used to obtain
the choice of the given choice member.

Replace it with sym_get_choice_menu(), which retrieves the choice
without relying on P_CHOICE.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

A_NORMAL is zero, so the attribute is set to the default A_NORMAL
without explicit assignment.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Just trivial cleanups.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Previously, optional bool choices met the following conditions
simultaneously:

 - sym_is_choice(sym)
 - sym_is_changeable(sym)
 - type == S_BOOLEAN

It no longer occurs since 6a1215888e23 ("kconfig: remove 'optional'
property support"). Remove the dead code.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>