build: auto-generate CONFLICTS for package variants sharing PROVIDES

Packages using PROVIDES to declare virtual package alternatives (like
tc-tiny, tc-bpf, tc-full all providing 'tc') could be simultaneously
selected as =y, causing installation conflicts. The PROVIDES mechanism
only handles dependency resolution, not mutual exclusion.

Add add_implicit_provides_conflicts() to automatically generate CONFLICTS
from default variants to non-default variants sharing the same PROVIDES.
This ensures only one variant can be built-in (=y) at a time.

Skip generating implicit conflicts when the non-default already has
explicit CONFLICTS with the default, to avoid Kconfig dependency cycles
with the select-based dependency resolution.

Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/scripts/package-metadata.pl b/scripts/package-metadata.pl
index 82bd4360f3bb9f0bf214a3fb10b68910e537c6e6..518dae2dfdfaac5fa47ec9d122b06937f822309d 100755 (executable)
--- a/scripts/package-metadata.pl
+++ b/scripts/package-metadata.pl
@@ -255,6 +255,52 @@ sub mconf_conflicts {
        return $res;
 }
 
+sub add_implicit_provides_conflicts {
+       foreach my $provide (keys %vpackage) {
+               next if $provide =~ /-any$/;
+
+               my $providers = $vpackage{$provide};
+               next unless $providers && @$providers > 1;
+
+               my $default_pkg;
+               my @non_defaults;
+
+               foreach my $pkg (@$providers) {
+                       next if $pkg->{buildonly};
+                       if ($pkg->{variant_default}) {
+                               $default_pkg = $pkg;
+                       } else {
+                               push @non_defaults, $pkg;
+                       }
+               }
+
+               next unless $default_pkg && @non_defaults;
+
+               my %existing_conflicts;
+               if ($default_pkg->{conflicts}) {
+                       %existing_conflicts = map { $_ => 1 } @{$default_pkg->{conflicts}};
+               }
+
+               foreach my $non_default (@non_defaults) {
+                       next if $existing_conflicts{$non_default->{name}};
+
+                       my $already_conflicts = 0;
+                       if ($non_default->{conflicts}) {
+                               foreach my $c (@{$non_default->{conflicts}}) {
+                                       if ($c eq $default_pkg->{name}) {
+                                               $already_conflicts = 1;
+                                               last;
+                                       }
+                               }
+                       }
+                       next if $already_conflicts;
+
+                       $default_pkg->{conflicts} ||= [];
+                       push @{$default_pkg->{conflicts}}, $non_default->{name};
+               }
+       }
+}
+
 sub print_package_config_category($) {
        my $cat = shift;
        my %menus;
@@ -350,6 +396,7 @@ sub print_package_overrides() {
 
 sub gen_package_config() {
        parse_package_metadata($ARGV[0]) or exit 1;
+       add_implicit_provides_conflicts();
        print "menuconfig IMAGEOPT\n\tbool \"Image configuration\"\n\tdefault n\n";
        print "source \"package/*/image-config.in\"\n";
        if (scalar glob "package/feeds/*/*/image-config.in") {