Re: [Boost-build] merge request

Subject: Re: [Boost-build] merge request
From: Phillip Seaver (phil_at_[hidden])
Date: 2014-06-24 07:56:21

On 6/24/14, 4:32 AM, Juraj Ivanèiæ wrote:
> On 22.6.2014. 15:46, Jürgen Hunold wrote:
>
>> Yes, of course. I was musing about the ML complaints/requests  that
>> b2 should
>> honour visual commandline prompts. If this had been easy, it would
>> have been
>> nice to have. But the speed improvements are more important.
>
> Some additional things to consider.
>
> * Should these scripts be created on each b2 invocation, even if they
> already exist?
>
> My first thought was yes, but an unfortunate consequence is that you
> will have targets updating on a fully built project. In addition,
> parallel b2 builds might interfere with each other. Is it OK to assume
> if a script already exists that its content is valid? Perhaps some
> combination of the two? E.g. assume that the script is valid unless
> --force-msvc-script-gen is passed on the command line.

Can you make them dependent on the .jam file that generated them?  And
the original batch files, if you're using them to create the scripts (I
haven't looked at the patch, so I'm just guessing).  I doubt they'll
change often, if at all, but it seems safer.

One thing I've thought of before that might be helpful in this case
would be a way to generate a new version of a file and compare it to the
existing file.  If the new version is different, replace the file,
otherwise, leave it alone.  It would have to happen before b2 checked to
see the timestamp of a dependency, though.

> * Should I add a command line option to restore old behavior, just in
> case? Something like --no-msvc-script-gen?

It's probably good to have a way to turn it off without having to revert
the changes.  Something you can set in user or system configuration
might be more helpful, so you can turn it off without having to remember
to use the argument every time.

Phillip