--config=force repro

myfile.c

#include <stdio.h>

int some_func() {
    printf("Yes");
    return 0;
}

SConstruct

AddOption('--show_bug', action='store_true', dest='show_bug', default=False,
          help="Show the config=force bug")

env=Environment()
conf = Configure(env)
if not conf.CheckCXXHeader('vector.h'):
    print 'vector.h must be installed!'

# Don't need this to cause the issue
# env = conf.Finish()

if not GetOption('show_bug'):
    print("Should work properly")
    env=Environment()
else:
    print("================================================================================================")
    print("Should rebuild when not needed because Configure with --config=force ")
    print("polutes the referenced environment's decider with a decider to force all config steps to rebuild")
    print("When run with --debug=explain will show all sources/implicits as changed")
    print("================================================================================================")


env.Object("myfile.c", CPPPATH=["."])