[cmake-developers] [CMake 0016017]: Setting OPTION to ON results in FALSE

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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https://cmake.org/Bug/view.php?id=16017 
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Reported By:                Abai
Assigned To:                
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Project:                    CMake
Issue ID:                   16017
Category:                   CMake
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     new
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Date Submitted:             2016-03-14 10:37 EDT
Last Modified:              2016-03-14 10:37 EDT
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Summary:                    Setting OPTION to ON results in FALSE
Description: 
It seems that setting an arbitrary option to ON results in variable to be set to
OFF instead. I am certain that the variable is not cached too. See the example
below to reproduce.

Here is the output from the attached CMakeLists.txt:

-- The C compiler identification is AppleClang 7.0.2.7000181
-- The CXX compiler identification is AppleClang 7.0.2.7000181
-- Check for working C compiler:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc
-- Check for working C compiler:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc
-- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++
-- Check for working CXX compiler:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++
-- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- WAX is not defined.
-- Setting WAX=ON.
-- Results in WAX=OFF
-- Configuring done
-- Generating done

The only workaround I found around is (FORCE is required even with empty cache):

SET(WAX ON CACHE BOOL "" FORCE)

Steps to Reproduce: 
PROJECT(OPTION_BUG)

CMAKE_MINIMUM_REQUIRED(VERSION 3.5.0 FATAL_ERROR)

IF(NOT DEFINED WAX)
    MESSAGE(STATUS "WAX is not defined.")
ENDIF()
MESSAGE(STATUS "Setting WAX=ON.")
OPTION(WAX ON)
MESSAGE(STATUS "Results in WAX=${WAX}")

Additional Information: 
CMake version 3.5.0 installed with home-brew on OSX 10.11.3
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Issue History 
Date Modified    Username       Field                    Change               
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2016-03-14 10:37 Abai           New Issue                                    
2016-03-14 10:37 Abai           File Added: CMakeLists.txt                    
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