On 19-Oct-15 19:30, Brad King wrote:
On 10/15/2015 03:58 PM, Ruslan Baratov wrote:
3. Apply changes to CMakeLists.txt "immediately", CMakeLists.txt modification
time 105
4. Run rebuild: `cmake --build _builds`. Since CMakeLists.txt (105) is not
"newer"
then Makefile (105) there will be no regenerate command run and Makefile
remains the same
Error can be easily reproduced on Apple HFS file system with unit = 1s (I hit this
problem doing changes even manually) but in general that's the "feature" of
native make tool + file system date resolution. Here is the similar test for Linux with
ext4:
Test: https://github.com/forexample/date-resolution-test
Log: https://travis-ci.org/forexample/date-resolution-test/builds/85021483
This is a fundamental limitation of buildsystems that use file timestamps.
Your example shows that even plain "make" has this problem. One simply
must use a workflow that does not involve changing files "immediately".
It's not that bad. When manually entering commands it is very hard to
type that fast. When scripting commmands the script can delay where
needed.
I've already heard all this arguments and can only reply mine again :)
* I've hit this while doing manual changes for Xcode project on Apple's
HFS with 1s resolution
* I don't want to patch every script. To be precise I prefer to "Fix
something in one place so it works 100% and forget about it" then "Every
time I start creating script I should remember that..."
There are a lot of scenarios where such problems can occurs, e.g. installing
files (reproducible on OSX and Linux):
* https://cmake.org/pipermail/cmake-developers/2015-October/026692.html
This is a separate issue because it is about CMake truncating timestamps
rather than the filesystem doing it.
Well yes, I was not very accurate with this statement, but in general
it's very similar (if CMake truncation precision == file system date
resolution then we have same situation) and "sleeping-guard" will fix it
too.
As I've mentioned I have a wrapper already so I've applied the "sleep"
functionality there. It fix all issues of 1-3 test case, so this is
closed for me now.
Thanks, Ruslo
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