[cmake-developers] [CMake 0014920]: find_package PythonInterp & PythonLibs fails if packages have been found previously

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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http://www.cmake.org/Bug/view.php?id=14920 
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Reported By:                George Sakhnovsky
Assigned To:                
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Project:                    CMake
Issue ID:                   14920
Category:                   CMake
Reproducibility:            always
Severity:                   minor
Priority:                   low
Status:                     new
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Date Submitted:             2014-05-16 11:19 EDT
Last Modified:              2014-05-16 11:19 EDT
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Summary:                    find_package PythonInterp & PythonLibs fails if
packages have been found previously
Description: 
The following are set in the main CMakeLists.txt:

set (PYTHON_EXECUTABLE "${ADS_DIR}/Python_2_7_3/Win32/python.exe")
set (PYTHON_INCLUDE_DIR "${ADS_DIR}/Python_2_7_3/include")
set (PYTHON_LIBRARY "${ADS_DIR}/Python_2_7_3/Win32/libs/python27.lib")

The first time find_package(PythonInterp) or find_package(PythonLibs) are
called, whether from the main CMakeLists.txt or that added via add_subdirectory,
the call is successful:

Found PythonInterp: D:/tfs/ADSDIR/Python_2_7_3/Win32/python.exe (found version
"2.7.3") 
Found PythonLibs: D:/tfs/ADSDIR/Python_2_7_3/Win32/libs/python27.lib (found
version "2.7.3") 

However, from this point on, any time find_package(PythonInterp) or
find_package(PythonLibs) are called, they fail and seemingly remove all
knowledge of the python instance being found, including un-setting
PYTHONINTERP_FOUND and PYTHONLIBS_FOUND:

Could NOT find PythonInterp (missing:  PYTHON_EXECUTABLE) (found version
"2.7.3")
Could NOT find PythonLibs (missing:  PYTHON_LIBRARIES PYTHON_INCLUDE_DIRS)

This is in contradiction to how find_package works with other targets such as QT
and VTK.

As a temporary band-aid I added conditionals:

#if (NOT PYTHONLIBS_FOUND)
    FIND_PACKAGE(PythonLibs)
#endif (NOT PYTHONLIBS_FOUND)

Is this behavior of add_package by design or a bug?
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Issue History 
Date Modified    Username       Field                    Change               
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2014-05-16 11:19 George SakhnovskyNew Issue                                    
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