Re: [OSSTEST PATCH 0/2] ts-xen-build: explicitly enable/disable configure features

[Juergen Gross <jgross@xxxxxxxx>]

On 27.10.21 19:02, Ian Jackson wrote:
> The existing code depends on precisely whether the non-default option
> appearing in the configure script is indeed the opposite of the option
> we want to pass.
>
> Right now it seems to be working but this seems fragile.  Do it
> differently.
>
> I have verified that with current Xen, on arm64:
>
>     + egrep -q -- '--disable-xend|--enable-xend' tools/configure
>     + egrep -q -- '--disable-ovmf|--enable-ovmf' tools/configure
>     + enable_opts=' --enable-ovmf'
>     + egrep -q -- '--disable-qemu-traditional|--enable-qemu-traditional' 
> tools/configure
>     + enable_opts=' --enable-ovmf --disable-qemu-traditional'
>     + ./configure --sysconfdir=/etc --enable-ovmf --disable-qemu-traditional
>
> and on amd64:
>
>     + egrep -q -- '--disable-xend|--enable-xend' tools/configure
>     + egrep -q -- '--disable-ovmf|--enable-ovmf' tools/configure
>     + enable_opts=' --enable-ovmf'
>     + egrep -q -- '--disable-qemu-traditional|--enable-qemu-traditional' 
> tools/configure
>     + enable_opts=' --enable-ovmf --enable-qemu-traditional'
>     + ./configure --sysconfdir=/etc --enable-ovmf --enable-qemu-traditional
>
> Juergen, I would appreciate a review from you.  I think I would like
> this in osstest production before changing the qemu trad build default
> in Xen.
Far from being a Perl expert I agree this is a sensible approach and it
should do the right thing.

It will still depend on no unsupported option being mentioned in any
comment, e.g. "# option --enable-foo is no longer supported" will result
in a wrong positive when testing for feature "foo". In the end this will
break the build, so it should be easy to detect in case this happens
some time in the future.

As there is no way to print out all supported options, this could only
be solved by adding "--disable-option-checking", which has other
disadvantages.

You can add my:

Reviewed-by: Juergen Gross <jgross@xxxxxxxx>


Juergen

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