Bug 9736 – VS2010 project file does full rebuild every time

For some reason, the VS2010 project never appears to be "cleanly built" - every time I hit build or run, it rebuilds DMD entirely, starting from compiling and running idgen. I can reproduce the problem with both VS2010 and 2012. I've tried to enable CPS diagnostics by adding the system.diagnostics XML snippet to devenv.exe.config [1], but this has produced no insightful output. This flaw is not present in the VS2008 project file. [1]: http://blogs.msdn.com/b/vsproject/archive/2009/07/21/enable-c-project-system-logging.aspx

Converting the VS2008 project file to VS2010 created a VS2010 project file that does not exhibit the problem.

And now it doesn't work again. And when I run the conversion again, only optabgen would run every time. Looks like a VS bug.

VS2010's CPS diagnostics output was more helpful. Buried, I found the line: Information: 0 : Project 'C:\Projects\Extern\D\dmd\src\dmd_msc.vcxproj' not up to date because build input 'C:\PROJECTS\EXTERN\D\DMD\SRC\BACKEND\CPP.H' is missing.

OK... after removing nonexistent files from the project, Visual Studio acknowledges that the project is built right after a build. However, now, after touching one source file, VS still reruns idgen/optabgen/etc.

Yes, msbuild is pretty horrible. Non existing files in the project cause it to think it needs update, but won't find anything to do. I usually use VS2008, but I don't have problems with unnecessary rebuilding the generated files with VS2012. They do have dependencies to a few source files though (e.g. mtype.h).

I've set the msbuild debug level to "Diagnostic". In the build log file, I see this line: "Forcing rebuild of source file "C:\Projects\Extern\D\dmd\src\idgen.c" due to a change in the command line since the last build. (TaskId:16)"

I found the problem. It was caused by newlines in the custom build tools' command line. I've replaced the "if" lines with the && operator and the problem is gone.

https://github.com/D-Programming-Language/dmd/pull/1756 Rainer, would you mind reviewing that?

Commit pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/7721267c2c9f1caa0876a8e00cba48ae831fa7e8 Update VS2010 project files (Issue 9736)

Thanks!