Fix a few bugs in the encoding when imposing constraints on build deps only

These bugs would show up when we try to split nodes by
imposing different targets or different compilers to all
build dependencies.

1 files changed, 12 insertions, 14 deletions

diff --git a/lib/spack/spack/solver/concretize.lp b/lib/spack/spack/solver/concretize.lp
index f810abc592..68ff6b4aa3 100644
--- a/lib/spack/spack/solver/concretize.lp
+++ b/lib/spack/spack/solver/concretize.lp
@@ -42,11 +42,11 @@ max_nodes(Package, 1) :- virtual(Package).
 :- provider(_, VirtualNode), not attr("virtual_node", VirtualNode).
 :- provider(PackageNode, _), not attr("node", PackageNode).
 
-:- attr("root", node(ID, PackageNode)), ID> root_node_id.
+:- attr("root", node(ID, PackageNode)), ID > root_node_id.
 
-% Root nodes cannot depend on non-root nodes if the dependency is "link" or "run"
-:- attr("depends_on", node(root_node_id, _), node(ID, _), "link"), ID != root_node_id.
-:- attr("depends_on", node(root_node_id, _), node(ID, _), "run"),  ID != root_node_id.
+% Nodes in the "root" unification set cannot depend on non-root nodes if the dependency is "link" or "run"
+:- attr("depends_on", node(root_node_id, Package), node(ID, _), "link"), ID != root_node_id, unification_set("root", node(root_node_id, Package)).
+:- attr("depends_on", node(root_node_id, Package), node(ID, _), "run"),  ID != root_node_id, unification_set("root", node(root_node_id, Package)).
 
 % Rules on "unification sets", i.e. on sets of nodes allowing a single configuration of any given package
 unify(SetID, PackageName) :- unification_set(SetID, node(_, PackageName)).
@@ -260,7 +260,6 @@ condition_set(PackageNode, PackageNode, link_run) :- attr("node", PackageNode).
 condition_set(PackageNode, PackageNode, link_run) :- provider(PackageNode, VirtualNode).
 condition_set(PackageNode, VirtualNode, link_run) :- provider(PackageNode, VirtualNode).
 
-:- condition_set(node(root_node_id, Package), node(ID, A1), link_run), ID > root_node_id.
 
 condition_set(ID, DependencyNode, link_run)
   :- condition_set(ID, PackageNode, link_run),
@@ -447,20 +446,22 @@ error(1, Msg)
 
 % if a package depends on a virtual, it's not external and we have a
 % provider for that virtual then it depends on the provider
-attr("depends_on", PackageNode, ProviderNode, Type)
+1 { attr("depends_on", PackageNode, ProviderNode, Type) : provider(ProviderNode, node(VirtualID, Virtual)) } 1
   :- dependency_holds(PackageNode, Virtual, Type),
-     provider(ProviderNode, node(VirtualID, Virtual)),
+     virtual(Virtual),
      not external(PackageNode).
 
 attr("virtual_on_edge", PackageNode, ProviderNode, Virtual)
   :- dependency_holds(PackageNode, Virtual, Type),
-     provider(ProviderNode, node(VirtualID, Virtual)),
+     attr("depends_on", PackageNode, ProviderNode, Type),
+     provider(ProviderNode, node(_, Virtual)),
      not external(PackageNode).
 
 % dependencies on virtuals also imply that the virtual is a virtual node
 1 { attr("virtual_node", node(0..X-1, Virtual)) : max_nodes(Virtual, X) }
   :- dependency_holds(PackageNode, Virtual, Type),
-     virtual(Virtual), not external(PackageNode).
+     virtual(Virtual),
+     not external(PackageNode).
 
 % If there's a virtual node, we must select one and only one provider.
 % The provider must be selected among the possible providers.
@@ -1242,11 +1243,8 @@ build(PackageNode) :- not attr("hash", PackageNode, _), attr("node", PackageNode
 %   200+        Shifted priorities for build nodes; correspond to priorities 0 - 99.
 %   100 - 199   Unshifted priorities. Currently only includes minimizing #builds.
 %   0   -  99   Priorities for non-built nodes.
-build_priority(PackageNode, 200) :- build(PackageNode), attr("node", PackageNode), optimize_for_reuse().
-build_priority(PackageNode, 0)   :- not build(PackageNode), attr("node", PackageNode), optimize_for_reuse().
-
-% don't adjust build priorities if reuse is not enabled
-build_priority(PackageNode, 0)   :- attr("node", PackageNode), not optimize_for_reuse().
+build_priority(PackageNode, 200) :- build(PackageNode), attr("node", PackageNode).
+build_priority(PackageNode, 0)   :- not build(PackageNode), attr("node", PackageNode).
 
 % don't assign versions from installed packages unless reuse is enabled
 % NOTE: that "installed" means the declared version was only included because