[LEDE-DEV] [PATCH] metadata: compile dependencies only when the package is selected

[Yousong Zhou]

This is intended to reduce build time for situations like the following
where python and python-six and their dependencies could still be built
as long as any subpackage within the srcpackage was selected regardless
of the selection state of openvswitch-python

    define Package/openvswitch-python
      ...
      DEPENDS:=+python +python-six
    endef

Previously we work around this by specifying the dependency as
+PACKAGE_openvswitch-python:python, which is unintuitive

Signed-off-by: Yousong Zhou <yszhou4tech at gmail.com>
---
 scripts/package-metadata.pl | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/scripts/package-metadata.pl b/scripts/package-metadata.pl
index 53bb45a..b827154 100755
--- a/scripts/package-metadata.pl
+++ b/scripts/package-metadata.pl
@@ -382,6 +382,7 @@ sub gen_package_mk() {
 		my %deplines = ('' => {});
 
 		foreach my $pkg (@{$src->{packages}}) {
+			my @pkgdeplines;
 			foreach my $dep (@{$pkg->{depends}}) {
 				next if ($dep =~ /@/);
 
@@ -410,10 +411,17 @@ sub gen_package_mk() {
 					}
 					my $depline = get_conditional_dep($condition, $depstr);
 					if ($depline) {
-						$deplines{''}{$depline}++;
+						push @pkgdeplines, $depline;
 					}
 				}
 			}
+			if (@pkgdeplines) {
+				my $depstr = join(' ', @pkgdeplines);
+				if ($depstr) {
+					my $depline = get_conditional_dep('PACKAGE_'.$pkg->{name}, $depstr);
+					$deplines{''}{$depline}++;
+				}
+			}
 
 			my $config = '';
 			$config = sprintf '$(CONFIG_PACKAGE_%s)', $pkg->{name} unless $pkg->{buildonly};
@@ -486,8 +494,7 @@ sub gen_package_mk() {
 		}
 
 		foreach my $suffix (sort keys %deplines) {
-			my $depline = join(" ", sort keys %{$deplines{$suffix}});
-			if ($depline) {
+			for my $depline (sort keys %{$deplines{$suffix}}) {
 				$line .= sprintf "\$(curdir)/%s/compile += %s\n", $src->{path}.$suffix, $depline;
 			}
 		}
-- 
1.8.3.1