[CMake] Run clean before automatically re-running cmake?

[Matthew Woehlke]

On 2014-02-12 11:35, Abe Bachrach wrote:
> The Makefile that cmake generates includes a rule to automatically re-run
> cmake if any of the input CMakelists.txt files change.
>
> Currently, if you change the name of an executable target (or library), it
> will leave the old file in the output location, and then after re-running
> cmake, the Makefile will not have any record of it, so running make clean
> won't remove it.
>
> I would rather have the rule call make clean before re-running cmake so
> that such stray outputs are not left around.
>
> Is there any way to accomplish this?

What you really want is to record the "old" list of output files, re-run 
CMake, then remove any files on that list that no longer have rules to 
generate them. If you do a complete 'clean' you will delete and have to 
rebuild more than is necessary (which might even be nothing e.g. if 
CMake is being re-run because you added a debugging message).

While that's probably hard to impossible¹ with 'make', I mention it 
because this feature (as described above) has at least been discussed 
for ninja², which does have the ability to implement it. (I'm not sure 
if it actually has been implemented or not, though.)

(¹ Use of recursive makefiles here doesn't help; probably each makefile 
would have to implement this logic, and each parent would have to know 
how to deal with directories that no longer exist in the build.)

(¹ http://martine.github.io/ninja/)

-- 
Matthew