On Sun, May 19, 2024 at 6:22 PM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > 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 actually unset, while the expectation is CONFIG_B=y. > > The reason for the issue is because Kconfig compares the tristate values > as strings. > > Currently, the .type fields of the constant symbols, 'y', 'm', and 'n' > 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 small than 'n' if compared as strings (since the ASCII small than -> smaller than -- Best Regards Masahiro Yamada
