Problem: CONFIG(debug,debug|release) and CONFIG(release,deubg|release) are always evaluated wherever debug or release is choosen in Qt Creator 2.8.1 for Linux.

My configuration in Qt Creator application (stock - default for new project):

Projects->Build Settings->Debug Build Steps:
  qmake build configuration: Debug
  Effective qmake call: qmake2 proj.pro -r -spec linux-gnueabi-oe-g++ CONFIG+=debug

Projects->Build Settings->Release Build Steps:
  qmake build configuration: Release
  Effective qmake call: qmake2 proj.pro -r -spec linux-gnueabi-oe-g++

My configuration in proj.pro:

message(Variable CONFIG:)
message($$CONFIG)
CONFIG(debug,debug|release)
{
    message(Debug build)
}
CONFIG(release,debug|release)
{
    message(Release build)
}

Output on console for Debug:

Project MESSAGE: Variable CONFIG:
Project MESSAGE: lex yacc warn_on debug uic resources warn_on release incremental link_prl no_mocdepend release stl qt_no_framework debug console
Project MESSAGE: Debug build
Project MESSAGE: Release build

Output on console for Release:

Project MESSAGE: Variable CONFIG:
Project MESSAGE: lex yacc warn_on uic resources warn_on release incremental link_prl no_mocdepend release stl qt_no_framework console
Project MESSAGE: Debug build
Project MESSAGE: Release build

Under Windows 7 I didnt experienced any problem with such .pro configuration and it worked fine. I was desperate and modified .pro file:

CONFIG = test
message(Variable CONFIG:)
message($$CONFIG)
CONFIG(debug,debug|release)
{
    message(Debug build)
}
CONFIG(release,debug|release)
{
    message(Release build)
}

and I was suprised with the output:

Project MESSAGE: Variable CONFIG:
Project MESSAGE: test
Project MESSAGE: Debug build
Project MESSAGE: Release build

so even if I completly clean CONFIG variable it still see debug and release configuration.

What Im doing wrong?