[cmake-developers] [CMake 0015368]: ExternalProject's BUILD_ALWAYS flag doesn't clear any existing build stamp file

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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http://www.cmake.org/Bug/view.php?id=15368 
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Reported By:                peitschie
Assigned To:                
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Project:                    CMake
Issue ID:                   15368
Category:                   CMake
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
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Date Submitted:             2015-01-23 01:18 EST
Last Modified:              2015-01-23 01:18 EST
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Summary:                    ExternalProject's BUILD_ALWAYS flag doesn't clear
any existing build stamp file
Description: 
Setting the BUILD_ALWAYS flag on an external project should cause the build step
to always trigger. This was new in 3.1 from what I can see. Unfortunately, it
appears to do this by making the *next* stamp file created symbolic (see
https://github.com/Kitware/CMake/blob/master/Modules/ExternalProject.cmake#L1457).
This means that until the existing stamp file is deleted, or something else
causes a rebuild to occur, BUILD_ALWAYS has no effect

Steps to Reproduce: 
1. Create a CMake file with an external project, with BUILD_ALWAYS set to 0
2. Build the external project
3. Change the BUILD_ALWAYS flag to 1
4. Attempt to rebuild the external project, and note how the build step is never
executed.
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Issue History 
Date Modified    Username       Field                    Change               
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2015-01-23 01:18 peitschie      New Issue                                    
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