cmake: Fix wrong check for cmake bool #59839
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The check for the allow_empty property of a library asserted always as true. By removing the quotes around the variable, it is not asserted as a string. Signed-off-by: Matthias Gilch <[email protected]>
| @@ -882,7 +882,7 @@ foreach(zephyr_lib ${ZEPHYR_LIBS_PROPERTY}) | |||
| AND NOT ${lib_imported} | |||
| ) | |||
| get_property(allow_empty TARGET ${zephyr_lib} PROPERTY ALLOW_EMPTY) | |||
| if(NOT "${allow_empty}") | |||
| if(NOT ${allow_empty}) | |||
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The check for the allow_empty property of a library asserted always as
true.
Are you sure / what issue or false warning do you see ?
According to CMake docs: https://cmake.org/cmake/help/latest/command/if.html#string
if(<string>)
A quoted string always evaluates to false unless:
- The string's value is one of the true constants, or
and the true constants are:
True if the constant is 1, ON, YES, TRUE, Y, or a non-zero number (including floating point numbers)
So by keeping the quotes, then setting ALLOW_EMPTY to one of the above should result in the if(NOT "y") to become false and the warning not printed, but when ALLOW_EMPTY is not set, a warning is printed.
However, the proposed if(NOT ${allow_empty}) will expand into if(NOT ) if ALLOW_EMPTY is not set which will evaluate to false, meaning default behavior will suddenly be to allow empty libraries.
If a library is empty and the warning should be silenced, then that library should set the ALLOW_EMPTY property to true.
Like this:
zephyr/lib/posix/CMakeLists.txt
Line 48 in 5876cc5
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Thank you for your review.
Somehow I mixed up my terminals and did not notice that my test did not produce the warning anymore where allow empty was not set.
Nevertheless, I still have the warning for modules that are empty. But the issue for that is somewhere else...
The check for the allow_empty property of a library asserted always as true. By removing the quotes around the variable, it is not asserted as a string.