[cmake-developers] [CMake 0014297]: XCode: Real targets do not depend on ZERO_CHECK

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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http://www.cmake.org/Bug/view.php?id=14297 
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Reported By:                Oscar Korz
Assigned To:                
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Project:                    CMake
Issue ID:                   14297
Category:                   CMake
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     new
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Date Submitted:             2013-07-16 21:35 EDT
Last Modified:              2013-07-16 21:35 EDT
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Summary:                    XCode: Real targets do not depend on ZERO_CHECK
Description: 
ALL_BUILD is a dummy target that depends on all other targets. This is
convenient for building all the targets in the project. XCode supports parallel
builds, so targets that are not dependent on each other are built
simultaneously.

ZERO_CHECK is a dummy target that checks if the XCode project has become
invalidated due to changes to CMake files. It may regenerate the project that is
currently open.

In 2.8.11.2, only ALL_BUILD depends on ZERO_CHECK. If you build another specific
target, ZERO_CHECK will not execute. This means that the XCode project will not
validate itself. Building a specific executable is a convenient way to start
debugging it, so this is a very common use case for my colleagues.

Additionally, I am concerned that ZERO_CHECK is run in parallel with real
targets. Not only is this a wasted effort if the project needs to be
regenerated, but more importantly I'm concerned that if an arbitrary project
fails to compile, the ZERO_CHECK task may get terminated before it finishes and
I'm not sure what effect this would have on the build tree. I have not confirmed
this behavior, but I have noticed irregular behavior that is only occuring with
XCode projects.

Steps to Reproduce: 
1. Create an XCode project from CMake.

2. Change the target from ALL_BUILD to any real target (i.e. a library or
executable).

3. Modify a CMake file used by the project. I suggest modifying the definition
of the target you selected in step 2 as this is the worst case scenario.

4. Build the target (Command-B).
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Issue History 
Date Modified    Username       Field                    Change               
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2013-07-16 21:35 Oscar Korz     New Issue                                    
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