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<div class="moz-cite-prefix">On 08-Oct-15 21:03, Mantis Bug Tracker
wrote:<br>
</div>
<blockquote cite="mid:6934fe0768634bce98b2955754827845@cmake.org"
type="cite">
<pre wrap="">
The following issue has been ASSIGNED.
======================================================================
<a class="moz-txt-link-freetext" href="https://cmake.org/Bug/view.php?id=15769">https://cmake.org/Bug/view.php?id=15769</a>
======================================================================
Reported By: Ruslan Baratov
Assigned To: Brad King
======================================================================
Project: CMake
Issue ID: 15769
Category: CMake
Reproducibility: always
Severity: minor
Priority: normal
Status: resolved
Target Version: CMake 3.5
Resolution: fixed
Fixed in Version: CMake 3.5
======================================================================
Date Submitted: 2015-10-05 10:37 EDT
Last Modified: 2015-10-08 14:03 EDT
======================================================================
Summary: OS X: Filesystem timestamp checks use only 1s
resolution
Description:
`cmake --build` command doesn't trigger reconfiguration of the project on OS X
when CMakeLists.txt changed.
Example:
add_executable(foo foo.cpp) # file foo.cpp exists
cmake -H. -B_builds
cmake --build _builds
# OK
change:
add_executable(foo foo.cpp boo.cpp) # file boo.cpp not exists
cmake --build _builds
# expected error, but no error reported
Ready-to-run example can be found:
<a class="moz-txt-link-freetext" href="https://github.com/forexample/cmake-osx-no-reconfigure-bug">https://github.com/forexample/cmake-osx-no-reconfigure-bug</a>
Log from OS X machine:
* <a class="moz-txt-link-freetext" href="https://travis-ci.org/forexample/cmake-osx-no-reconfigure-bug/builds/83701171">https://travis-ci.org/forexample/cmake-osx-no-reconfigure-bug/builds/83701171</a>
Log for similar test on Linux machine:
* <a class="moz-txt-link-freetext" href="https://travis-ci.org/forexample/cmake-osx-no-reconfigure-bug/builds/83702953">https://travis-ci.org/forexample/cmake-osx-no-reconfigure-bug/builds/83702953</a>
CMake on Linux machine run reconfigure command and report an error:
cmake -H. -B_builds --check-build-system CMakeFiles/Makefile.cmake 0
-- Configuring done
CMake Error at CMakeLists.txt:4 (add_executable):
Cannot find source file:
boo.cpp
same error expected on OS X machine
======================================================================
----------------------------------------------------------------------
(0039511) Brad King (manager) - 2015-10-05 14:45
<a class="moz-txt-link-freetext" href="https://cmake.org/Bug/view.php?id=15769#c39511">https://cmake.org/Bug/view.php?id=15769#c39511</a>
----------------------------------------------------------------------
I can reproduce this when running 'make' directly without 'cmake --build':
-cmake --build _builds
+(cd _builds; make)
The problem is that the filesystem and/or make tool seem to have 1s timestamp
resolution. If I change the script to do "sleep 1" before the last "cp
CMakeBad.txt CMakeLists.txt" then it works.
----------------------------------------------------------------------
(0039512) Brad King (manager) - 2015-10-05 14:52
<a class="moz-txt-link-freetext" href="https://cmake.org/Bug/view.php?id=15769#c39512">https://cmake.org/Bug/view.php?id=15769#c39512</a>
----------------------------------------------------------------------
The issue may be where CMake decides whether it needs to re-run:
<a class="moz-txt-link-freetext" href="https://cmake.org/gitweb?p=cmake.git;a=blob;f=Source/cmFileTimeComparison.cxx;hb=v3.3.2#l147">https://cmake.org/gitweb?p=cmake.git;a=blob;f=Source/cmFileTimeComparison.cxx;hb=v3.3.2#l147</a>
The STAT_HAS_ST_MTIM code path may not be taken on this platform.
----------------------------------------------------------------------
(0039513) Brad King (manager) - 2015-10-05 14:54
<a class="moz-txt-link-freetext" href="https://cmake.org/Bug/view.php?id=15769#c39513">https://cmake.org/Bug/view.php?id=15769#c39513</a>
----------------------------------------------------------------------
Indeed, on OS X "struct stat" has:
struct timespec st_mtimespec;
instead of
struct timespec st_mtim;
----------------------------------------------------------------------
(0039518) Brad King (manager) - 2015-10-06 13:27
<a class="moz-txt-link-freetext" href="https://cmake.org/Bug/view.php?id=15769#c39518">https://cmake.org/Bug/view.php?id=15769#c39518</a>
----------------------------------------------------------------------
For reference, I've started a fix for this on the KWSys side here:
<a class="moz-txt-link-freetext" href="http://review.source.kitware.com/20258/">http://review.source.kitware.com/20258/</a>
----------------------------------------------------------------------
(0039519) Brad King (manager) - 2015-10-06 14:04
<a class="moz-txt-link-freetext" href="https://cmake.org/Bug/view.php?id=15769#c39519">https://cmake.org/Bug/view.php?id=15769#c39519</a>
----------------------------------------------------------------------
It looks like the underlying HFS filesystem only has 1s resolution:
<a class="moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/HFS_Plus">https://en.wikipedia.org/wiki/HFS_Plus</a>
This may not be possible to fix without a "sleep 1" in the test script.
----------------------------------------------------------------------
(0039548) Brad King (manager) - 2015-10-08 14:01
<a class="moz-txt-link-freetext" href="https://cmake.org/Bug/view.php?id=15769#c39548">https://cmake.org/Bug/view.php?id=15769#c39548</a>
----------------------------------------------------------------------
After the KWSys side learned to use st_mtimespec I've updated CMake too:
cmFileTimeComparison: Port to OS X nanosecond times
<a class="moz-txt-link-freetext" href="https://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=8d27b407">https://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=8d27b407</a>
----------------------------------------------------------------------
(0039549) Brad King (manager) - 2015-10-08 14:03
<a class="moz-txt-link-freetext" href="https://cmake.org/Bug/view.php?id=15769#c39549">https://cmake.org/Bug/view.php?id=15769#c39549</a>
----------------------------------------------------------------------
Marking as resolved because the proper API for ns resolution is now used.
However in practice the underlying filesystem may limit the resolution anyway.
Issue History
Date Modified Username Field Change
======================================================================
2015-10-05 10:37 Ruslan Baratov New Issue
2015-10-05 14:45 Brad King Note Added: 0039511
2015-10-05 14:52 Brad King Note Added: 0039512
2015-10-05 14:53 Brad King Summary Change of
CMakeLists.txt doesn't trigger reconfigure => OS X: Filesystem timestamp checks
use only 1s resolution
2015-10-05 14:54 Brad King Note Added: 0039513
2015-10-06 13:27 Brad King Note Added: 0039518
2015-10-06 14:04 Brad King Note Added: 0039519
2015-10-08 14:01 Brad King Note Added: 0039548
2015-10-08 14:03 Brad King Note Added: 0039549
2015-10-08 14:03 Brad King Assigned To => Brad King
2015-10-08 14:03 Brad King Status new => resolved
2015-10-08 14:03 Brad King Resolution open => fixed
2015-10-08 14:03 Brad King Fixed in Version => CMake 3.5
2015-10-08 14:03 Brad King Target Version => CMake 3.5
======================================================================
</pre>
</blockquote>
Hi,<br>
<br>
While viewing changes you've made I found an "interesting" behaviour
of CMake's install procedure. Since it's not about this bug exactly
I'm moving it to 'cmake-developers' list. Function
cmFileTimeComparisonInternal::TimesDiffer use only limited number of
digits of timestamp and used in install step. This may lead to the
similar bugs.<br>
<br>
Here is the result of my white-box testing skills:<br>
script:
<a class="moz-txt-link-freetext" href="https://github.com/forexample/cmake-header-install-bug/blob/master/run-test.sh">https://github.com/forexample/cmake-header-install-bug/blob/master/run-test.sh</a><br>
log:
<a class="moz-txt-link-freetext" href="https://travis-ci.org/forexample/cmake-header-install-bug/builds/84592318">https://travis-ci.org/forexample/cmake-header-install-bug/builds/84592318</a><br>
<blockquote><span id="1-193"></span><span id="1-194"></span>--
Up-to-date:
/Users/travis/build/forexample/cmake-header-install-bug/_install/include/foo.hpp<br>
1c1<br>
< Bad<br>
---<br>
> Good<br>
Error: file not installed!<br>
</blockquote>
So installed foo.hpp file is not updated. This may be quite
surprising in automated tools like git-bisect. Also I've found
`CMAKE_INSTALL_ALWAYS` environment variable but it's not documented.<br>
<br>
Thanks, Ruslo<br>
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