package-metadata: drop self-referencing rank from depends-on gates

Based on:
- 218aad6e2f re-emit a provider's depends
- 38824a1351 fold the select condition onto re-emitted deps
- 47d6b05ad3 provides-based dep resolution(%vpackage/@vdeps machinery)
- 1fd50531ca "<" rank comparison on provider selection

The provider-selection rank ('A<B', born in 1fd50531) is RHS-anchored
on the stanza owner. When a consumer +selects a provider of a PROVIDES
target served by >=2 providers, the provider's dependencies are
re-emitted into the consumer's kconfig block under this rank. A bare
@() arch/feature dep folded under it becomes:

  depends on !(PACKAGE_librespeed-cli-rust<PACKAGE_librespeed-common)
              || (aarch64||arm||i386||i686||loongarch64||mips||...)

Kconfig treats any occurrence of a symbol in a dependency edge as an
edge, even negated under '!() ||', so PACKAGE_librespeed-common lands
in its own dir_dep: a recursive dependency self-loop.

The self-reference reaches the owner's stanza through any re-emitted
dependency emitted as depends-on: provider '@()' arch gates, plain
deps on a second virtual that '||'-expand, and plain deps on ordinary
packages inheriting the rank-bearing parent. Rank is therefore
generated only for select emission: it is built into a separate
variable and folded into the select gate alone, while re-emission
carries the pre-rank negation instead (!OTHER / !(A||B) over all
leftovers, exactly as before 1fd50531). Within a stanza no depends-on
gate can therefore self-reference, except for self-providing
consumers (provide and depend on the same name), which keep
historical behavior; user conditions, parent conditions and all
select arbitration remain untouched.

Fixes: 1fd50531ca ("metadata: ensure one dependency provider to be y if a package is y")
Signed-off-by: Mario Andrés Pérez <mapb_@outlook.com>

scripts/package-metadata.pl

@@ -181,6 +181,8 @@ sub mconf_depends {
 		}
 		if ($flags =~ /\+/) {
 			my $vdep = $vpackage{$depend};
+			my $rank;
+			my $negation;
 			if ($vdep) {
 				my @vdeps;
 
@@ -196,22 +198,33 @@ sub mconf_depends {
 				$depend = shift @vdeps;
 
 				if (@vdeps > 1) {
-					$condition = ($condition ? "$condition && " : '') . join("&&", map { "PACKAGE_$_<PACKAGE_$pkgname" } @vdeps);
+					$rank = join("&&", map { "PACKAGE_$_<PACKAGE_$pkgname" } @vdeps);
+					$negation = '!('.join("||", map { "PACKAGE_$_" } @vdeps).')';
 				} elsif (@vdeps > 0) {
-					$condition = ($condition ? "$condition && " : '') . "PACKAGE_${vdeps[0]}<PACKAGE_$pkgname";
+					$rank = "PACKAGE_${vdeps[0]}<PACKAGE_$pkgname";
+					$negation = '!PACKAGE_'.$vdeps[0];
 				}
 			}
 
 			# Menuconfig will not treat 'select FOO' as a real dependency
 			# thus if FOO depends on other config options, these dependencies
 			# will not be checked. To fix this, we simply emit all of FOO's
-			# depends here as well.
-			$package{$depend} and push @t_depends, [ $package{$depend}->{depends}, $condition ];
+			# depends here as well. Re-emitted deps carry the pre-rank
+			# negation instead of the rank, as before 1fd50531.
+			my $reemit = $condition;
+			$reemit = ($reemit ? "$reemit && " : '') . $negation if defined $negation;
+			$package{$depend} and push @t_depends, [ $package{$depend}->{depends}, $reemit ];
 
 			$m = "select";
 			next if $only_dep;
 
 			$flags =~ /@/ or $depend = "PACKAGE_$depend";
+
+			# arbitration gate for select emission only (1fd50531's charter);
+			# re-emission above carries the negation instead of the rank
+			if (defined $rank) {
+				$condition = ($condition ? "$condition && " : '') . $rank;
+			}
 		} else {
 			my $vdep = $vpackage{$depend};
 			if ($vdep && @$vdep > 0) {