Re: [Qemu-devel] [PATCH] configure: re-add current options in config-host.mak

[Stefan Weil]

Am 24.11.2013 10:37, schrieb Michael S. Tsirkin:
> commit bdf523e6923f1e667055e947e71fc600549cefae
>     "configure: Add config.status to recreate the current configuration"
> moved current configure flags to config.status
>
> This makes sense, but this makes it harder to bisect problems that
> trigger with a specific set of flags only, since old configure is not
> smart enough to find them there.
>
> Simply add the options as a comment in the format
> old configure expected - they are then ignored by the new configure.
>
> Cc: Stefan Weil <address@hidden>
> Cc: Fam Zheng <address@hidden>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>  configure | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/configure b/configure
> index 508f6a5..f6d5ccd 100755
> --- a/configure
> +++ b/configure
> @@ -3797,6 +3797,7 @@ config_host_mak="config-host.mak"
>  echo "# Automatically generated by configure - do not modify" 
> >config-all-disas.mak
>  
>  echo "# Automatically generated by configure - do not modify" > 
> $config_host_mak
> +sed -n -e 's/exec/# Configured with:/p' config.status >> $config_host_mak
>  echo >> $config_host_mak
>  
>  echo all: >> $config_host_mak

Do we really need this? It only makes git bisect iterations from
versions after 2013-11-19 to versions before that date easier. If a
typical git bisect needs 10 steps, then in the worst cast 5 of them
won't automatically run configure. This is normally not a big problem
because there is already a configuration, and many changes of file
configure don't change that configuration.

It's always possible to run configure explicitly at each step of the
bisection process, so in case of doubt there is an easy fall-back
solution. Before I introduced automatic reconfiguration, calling
configure + make was normal for git bisect.

I'd prefer to avoid code like this patch which is only marginally useful
in a very specific development use case. People who can run git bisect
will be able to help themselves if they really get a problem without the
patch.

Regards,
Stefan