[pkg-php-pear] Add set_sourcedir to Debian::Debhelper::Buildsystem

[Niels Thykier]

On Mon, 27 May 2013 10:29:42 +0200 Mathieu Parent
<math.parent at gmail.com> wrote:
> Package: debhelper
> Version: 9.20130518
> Severity: whishlist
> X-Debbugs-CC: pkg-php-pear at lists.alioth.debian.org
> 
> Hi Joey,
> 
> For the pkg-php-tools [1] package, which enhance debhelper, I need to
> change the sourcedir when building PECL [2] package.
> 
> [1]: http://anonscm.debian.org/gitweb/?p=pkg-php/pkg-php-tools.git;a=summary
> [2]: http://www.php.net/manual/en/install.pecl.phpize.php
> 
> The wanted workflow on configure:
> - set sourcedir to Foo-0.0.0
> - phpize
> - pass to parent Debian::Debhelper::Buildsystem::autoconf configure()
> - set sourcedir back to top
> 
> The wanted workflow on build:
> - set sourcedir to Foo-0.0.0
> - pass to parent Debian::Debhelper::Buildsystem::autoconf build()
> - set sourcedir back to top
> 
> The wanted workflow on install:
> - set sourcedir to Foo-0.0.0
> - pass to parent Debian::Debhelper::Buildsystem::autoconf install()
> - set sourcedir back to top
> 
> Wanted API:
> - push_sourcedir (with the same checks as in
> Debian::Debhelper::Buildsystem::new())
> - pop_sourcedir
> 
> Or:
> - set_sourcedir (with the same checks as in
> Debian::Debhelper::Buildsystem::new())
> 
> I'm open to any better solution.
> 
> Regards
> --
> Mathieu Parent
> 
> 

Hi Mathieu,

Apologies for the long wait before picking this up.

Since you filed this bug, debhelper has gotten a new model for build
systems that may be relevant to this case.  The described build flows
looks a look existing build generator flows (a la meson+ninja or
cmake+make[1]).

The phppear have some differences to this theme as such debhelper does
not currently support exactly the phppear use-case.  I am hoping we can
come to a solution on that.

If phppear would be converted to generator buildsystem like meson, then
it would probably look something like this (mix-pseudo code, mix real code):


"""
# Remove 'use base "Debian::Debhelper::Buildsystem::autoconf";'
[...]

sub IS_GENERATOR_BUILD_SYSTEM {
	return 1;
}

sub SUPPORTED_TARGET_BUILD_SYSTEMS {
	return qw(autoconf);
}

sub _get_peardir {
	[...]
}

# This sub does *not* exist yet
sub _initialize_target_buildsystem {
	my ($this, $target_bs_options, @args) = shift;
	$target_bs_options->{'sourcedir'} = $this->_get_peardir;
	$target_bs_options->{'builddir'} = $this->_get_peardir;
	return $this->SUPER::_initialize_target_buildsystem(
			$target_bs_options, @args);
}

sub configure {
	my $this=shift;
	$this->get_targetbuildsystem->mkdir_builddir;
	$this->get_targetbuildsystem->doit_in_builddir('phpize');
	return $this->SUPER::configure(@_);
}

[...]
"""
The configure is from your concept description; I realise that the real
phppear build system is "slightly" more complex than that.


The most difficult issue is if you need to extract data to make
_get_peardir work, which may only be available if phppear is a valid
buildsystem for the concrete package.  However, debhelper currently
initializes the target buildsystem immediately and we rely on this
elsewhere in debhelper (e.g. in dh_auto_configure --list).


Just to confirm I got some details correct:
 * Is it correctly understood of me that phppear *conditionally* uses
   autoconf as a generated build system (i.e. there are packages where
   phppear does everything without ever using the autoconf bits)?

 * Is it correctly understood that phppear potentially needs two
   distinct "build directories"?  One for itself and a generated one for
   the autoconf parts?

 * Is the exact name returned by _get_peardir important or just "nice to
   have"?




Finally, a few drive-by remarks after reviewing the phppear build system
(in case they are useful to you):

 * _get_mainpackage looks like an expensive version of $dh{MAINPACKAGE}
   (with some theoretical corner cases where dh_listpackages might give
   you a different result).
   - Is anything preventing you from using $dh{MAINPACKAGE}?

 * If you like to avoid shell, then the complex_doit call can be
   replaced by using doit({stdout => $path}, ...).  Requires buster
   or later (I can dig out the exact version of debhelper if relevant,
   but I did not see any backports for pkg-php-tools, so I assumed it
   was not relevant).


Thanks,
~Niels

[1] Strictly speaking, autoconf should be autoconf+make.  But historical
reasons prevent the split.