[virt-tools-list] [PATCH] add AM_MAINTAINER_MODE macro

[Daniel P. Berrange]

On Fri, Oct 15, 2010 at 02:44:38PM +0200, Guido Günther wrote:
> On Fri, Oct 15, 2010 at 01:18:16PM +0100, Daniel P. Berrange wrote:
> > On Fri, Oct 15, 2010 at 06:06:35AM -0600, Eric Blake wrote:
> > > On 10/15/2010 05:29 AM, Guido Günther wrote:
> > > >Hi,
> > > >On Wed, Sep 29, 2010 at 04:46:23PM +0200, Guido Günther wrote:
> > > 
> > > Odd - I cannot find the original mail, even when looking in the archives:
> > > https://www.redhat.com/archives/libvir-list/2010-September/date.html
> > > 
> > > >>Hi,
> > > >>Please add the AM_MAINTAINER_MODE macro to configure.ac for
> > > >>virt-manager. This allows downstream distributions to disable this
> > > >>feature so no autotools are required to build the package. The patch
> > > >>doesn't change behaviour for upstream:
> > > >>
> > > >>     http://www.gnu.org/software/hello/manual/automake/maintainer_002dmode.html
> > > 
> > > The automake manual recommends against maintainer mode:
> > > http://www.gnu.org/software/automake/manual/automake.html#maintainer_002dmode
> > > 
> > > >Several years ago François Pinard pointed out several arguments against 
> > > >this AM_MAINTAINER_MODE macro. Most of them relate to insecurity. By 
> > > >removing dependencies you get non-dependable builds: changes to sources 
> > > >files can have no effect on generated files and this can be very confusing 
> > > >when unnoticed. He adds that security shouldn't be reserved to maintainers 
> > > >(what --enable-maintainer-mode suggests), on the contrary. If one user has 
> > > >to modify a Makefile.am, then either Makefile.in should be updated or a 
> > > >warning should be output (this is what Automake uses missing for) but the 
> > > >last thing you want is that nothing happens and the user doesn't notice it 
> > > >(this is what happens when rebuild rules are disabled by 
> > > >AM_MAINTAINER_MODE).
> > > >
> > > >Jim Meyering, the inventor of the AM_MAINTAINER_MODE macro was swayed by 
> > > >François's arguments, and got rid of AM_MAINTAINER_MODE in all of his 
> > > >packages.
> > > 
> > > Furthermore, downstream distributions should not require autotools to 
> > > build a package if they do not make any changes to any of the 
> > > configure.ac/Makefile.am source files in the first place; and 
> > > conversely, if you ARE patching those files, then you WANT to rerun the 
> > > autotools and not silently disable them.
> > 
> > IIUC, this patch preserves that behaviour
> Yes. The patch preserves current behaviour...
> 
> > If you added  'AM_MAINTAINER_MODE()', then the auto-rebuild rules
> > would be disabled.  This patch adds 'AM_MAINTAINER_MODE([enable])'
> > which IIUC,  keeps the auto-rebuild rules enabled by default as
> > is normal behaviour when this macro isn't present at all. So the
> > end result is simply that we gain the --[dis|en]able-maintainer-mode
> > command line options, with no behavioural change elsewhere.
> 
> ...and gives us --disable-maintainer-mode. This way downstreams can
> disable maintainer mode and make sure they're not dependent on autotools
> when building the package.
> 
> I agree with Eric that this should be added to all virt-* packages.
> virt-manager was merely meant as a start to get into the discussion.

It gets my vote, because it doesn't change default behaviour, and gives 
downstream a choice.

Daniel
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