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IDProjectCategoryView StatusDate SubmittedLast Update
0015112CMakeCMakepublic2014-08-26 17:352015-03-02 08:57
ReporterJavier Martinez 
Assigned ToBrad King 
PrioritynormalSeverityminorReproducibilityalways
StatusclosedResolutionfixed 
PlatformWindowsOSWindowsOS VersionWin7-64
Product VersionCMake 3.0.1 
Target VersionCMake 3.1Fixed in VersionCMake 3.1 
Summary0015112: add_custom_command: Clarify documented relationship of multiple COMMANDs
DescriptionCMake generates incorrect commands in a custom build step causing builds to fail. The attached example exposes two issues:
- CMake inserts spaces around the statement in parenthesis which changes the variable value. In the attached example the CONF variable value is "Release " instead of "Release"
  Expected: if '$(Configuration)'=='Release-Internal' set (CONF=Release)
  Actual: if '$(Configuration)'=='Release-Internal' set ( CONF=Release )
  Workaround: if there's no else clause the w/a is to not use parenthesis

- If the content of a variable is used at the beginning of a command CMake will wrap it in additional percent (%) characters making the command invalid.
  Expected: %CMDLINE%
  Actual: %%CMDLINE%%
  Workaround: use conditional expressions to avoid the variable be at the beginning, for example ECHO "Running command" && %CMDLINE%
Steps To Reproducecmake_minimum_required(VERSION 3.0)

add_custom_target(Test
)

add_custom_command(
    TARGET Test
    PRE_BUILD
    COMMAND set CONF=$(Configuration)
    COMMAND if '$(Configuration)'=='Release-Internal' set (CONF=Release)
    COMMAND set BUNDLE_FOLDER=Prebuilt/Windows/%CONF%/$(PlatformArchitecture)
    COMMAND set CMDLINE=7z.exe x -y %BUNDLE_FOLDER%/bundle.7z -o%BUNDLE_FOLDER%
    COMMAND echo %CMDLINE%
    COMMAND %CMDLINE%
    COMMENT "Extracting Bundle (failed)"
)

add_custom_command(
    TARGET Test
    POST_BUILD
    COMMAND set CONF=$(Configuration)
    COMMAND if '$(Configuration)'=='Release-Internal' set CONF=Release
    COMMAND set BUNDLE_FOLDER=Prebuilt/Windows/%CONF%/$(PlatformArchitecture)
    COMMAND set CMDLINE=7z.exe x -y %BUNDLE_FOLDER%/bundle.7z -o%BUNDLE_FOLDER%
    COMMAND echo %CMDLINE% && %CMDLINE%
    COMMENT "Extracting Bundle (succeed)"
)
Additional InformationCommand line to reproduce: cmake.exe CMakeLists.txt -G"Visual Studio 12" -B"CMakeOutput"
TagsNo tags attached.
Attached Filestxt file icon CMakeLists.txt [^] (902 bytes) 2014-08-26 17:35 [Show Content]

 Relationships

  Notes
(0036679)
David Cole (manager)
2014-08-27 07:51

 One workaround would be to write this all into a batch file, and use "COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/script.bat arg1 arg2"

Another workaround would be to use:
call %CMDLINE%

instead of just
%CMDLINE%

It's a legitimate bug report (but I didn't confirm it myself), but there are multiple ways to work around the issue.
(0036682)
Brad King (manager)
2014-08-27 09:34

 The add_custom_command COMMAND option expects full command lines rather than batch script fragments. After each command the generated script contains code to abort execution on failure. The only way to get a custom batch file is to generate it yourself.

It looks like you're trying to get per-configuration behavior. You can use file(GENERATE) to get a config-specific script generated with generator expressions like $<CONFIG>.
(0036689)
Javier Martinez (reporter)
2014-08-28 17:01

 > The add_custom_command COMMAND option expects full command lines rather than batch script fragments.
The documentation (http://www.cmake.org/cmake/help/v3.0/command/add_custom_command.html?highlight=add_custom_command [^]) doesn't make any mention of that but it does show support for multiple COMMANDs. What constitutes a 'full command line' anyways?

The notes have pretty good alternatives and thank you for providing them but I still feel the add_custom_command parser can be fixed to handle the corner cases described here. At the very least fix the documentation to list the parser limitations.
(0036702)
Brad King (manager)
2014-09-02 15:15

 Here is a documentation update:

 Help: Clarify add_custom_command multiple command behavior
 http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=412926d0 [^]
(0036748)
Javier Martinez (reporter)
2014-09-08 14:06

 Sorry to reopen the issue. I was on Vacation all of last week and couldn't provide feedback until today. The change is correct but it's only clear to me after reading the thread. Perhaps you should consider adding to the documentation that to execute complete shell scripts they need to be in their own file and use a COMMAND instruction to launch them.
(0036749)
Brad King (manager)
2014-09-08 14:16

 Help: Suggest in add_custom_command how to create a script
http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=1fdf4ff0 [^]
(0038114)
Robert Maynard (manager)
2015-03-02 08:57

 Closing resolved issues that have not been updated in more than 4 months.

 Issue History
Date Modified Username Field Change
2014-08-26 17:35 Javier Martinez New Issue
2014-08-26 17:35 Javier Martinez File Added: CMakeLists.txt
2014-08-27 07:51 David Cole Note Added: 0036679
2014-08-27 07:58 David Cole Summary Incorrect commands generated on bustom build step for Visual Studio => Incorrect commands generated on custom build step for Visual Studio
2014-08-27 09:34 Brad King Note Added: 0036682
2014-08-28 17:01 Javier Martinez Note Added: 0036689
2014-09-02 15:15 Brad King Summary Incorrect commands generated on custom build step for Visual Studio => add_custom_command: Clarify documented relationship of multiple COMMANDs
2014-09-02 15:15 Brad King Note Added: 0036702
2014-09-04 09:44 Brad King Assigned To => Brad King
2014-09-04 09:44 Brad King Status new => resolved
2014-09-04 09:44 Brad King Resolution open => fixed
2014-09-04 09:44 Brad King Fixed in Version => CMake 3.1
2014-09-04 09:44 Brad King Target Version => CMake 3.1
2014-09-08 14:06 Javier Martinez Note Added: 0036748
2014-09-08 14:06 Javier Martinez Status resolved => feedback
2014-09-08 14:06 Javier Martinez Resolution fixed => reopened
2014-09-08 14:16 Brad King Note Added: 0036749
2014-09-08 14:17 Brad King Status feedback => assigned
2014-09-08 14:17 Brad King Resolution reopened => open
2014-09-11 13:03 Brad King Status assigned => resolved
2014-09-11 13:03 Brad King Resolution open => fixed
2015-03-02 08:57 Robert Maynard Note Added: 0038114
2015-03-02 08:57 Robert Maynard Status resolved => closed

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