From a6d433b937ee7d418289b23585a6d53343f1f14e Mon Sep 17 00:00:00 2001
From: Massimiliano Culpo <massimiliano.culpo@gmail.com>
Date: Fri, 4 Dec 2020 16:27:03 +0100
Subject: [PATCH] concretizer: restrict maximizing variant values to MV
 variants (#20194)

---
 lib/spack/spack/solver/concretize.lp                 |  8 ++++++--
 lib/spack/spack/test/concretize.py                   |  4 ++++
 .../dep-with-variants-if-develop-root/package.py     | 11 +++++++++++
 .../packages/dep-with-variants-if-develop/package.py | 12 ++++++++++++
 4 files changed, 33 insertions(+), 2 deletions(-)
 create mode 100644 var/spack/repos/builtin.mock/packages/dep-with-variants-if-develop-root/package.py
 create mode 100644 var/spack/repos/builtin.mock/packages/dep-with-variants-if-develop/package.py

diff --git a/lib/spack/spack/solver/concretize.lp b/lib/spack/spack/solver/concretize.lp
index 2de7030ddf..acfed6f599 100644
--- a/lib/spack/spack/solver/concretize.lp
+++ b/lib/spack/spack/solver/concretize.lp
@@ -508,7 +508,9 @@ root(Dependency, 1) :- not root(Dependency), node(Dependency).
 % need to maximize their number below to ensure they're all set
 #maximize {
     1@13,Package,Variant,Value
-    : variant_not_default(Package, Variant, Value, Weight), root(Package)
+    : variant_not_default(Package, Variant, Value, Weight),
+    not variant_single_value(Package, Variant),
+    root(Package)
 }.
 #minimize{
     Weight@13,Provider
@@ -531,7 +533,9 @@ root(Dependency, 1) :- not root(Dependency), node(Dependency).
 % need to maximize their number below to ensure they're all set
 #maximize {
     1@8,Package,Variant,Value
-    : variant_not_default(Package, Variant, Value, Weight), not root(Package)
+    : variant_not_default(Package, Variant, Value, Weight),
+    not variant_single_value(Package, Variant),
+    not root(Package)
 }.
 
 % Try to maximize the number of compiler matches in the DAG,
diff --git a/lib/spack/spack/test/concretize.py b/lib/spack/spack/test/concretize.py
index fed0432f91..2e96eea4af 100644
--- a/lib/spack/spack/test/concretize.py
+++ b/lib/spack/spack/test/concretize.py
@@ -975,3 +975,7 @@ def test_all_patches_applied(self):
         spec.concretize()
         assert ((uuidpatch, localpatch) ==
                 spec['libelf'].variants['patches'].value)
+
+    def test_dont_select_version_that_brings_more_variants_in(self):
+        s = Spec('dep-with-variants-if-develop-root').concretized()
+        assert s['dep-with-variants-if-develop'].satisfies('@1.0')
diff --git a/var/spack/repos/builtin.mock/packages/dep-with-variants-if-develop-root/package.py b/var/spack/repos/builtin.mock/packages/dep-with-variants-if-develop-root/package.py
new file mode 100644
index 0000000000..00162ee200
--- /dev/null
+++ b/var/spack/repos/builtin.mock/packages/dep-with-variants-if-develop-root/package.py
@@ -0,0 +1,11 @@
+# Copyright 2013-2020 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+class DepWithVariantsIfDevelopRoot(Package):
+    """Package that adds a dependency with many variants only at @develop"""
+    homepage = "https://dev.null"
+
+    version('1.0')
+
+    depends_on('dep-with-variants-if-develop')
diff --git a/var/spack/repos/builtin.mock/packages/dep-with-variants-if-develop/package.py b/var/spack/repos/builtin.mock/packages/dep-with-variants-if-develop/package.py
new file mode 100644
index 0000000000..ecb11224b3
--- /dev/null
+++ b/var/spack/repos/builtin.mock/packages/dep-with-variants-if-develop/package.py
@@ -0,0 +1,12 @@
+# Copyright 2013-2020 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+class DepWithVariantsIfDevelop(Package):
+    """Package that adds a dependency with many variants only at @develop"""
+    homepage = "https://dev.null"
+
+    version('develop')
+    version('1.0')
+
+    depends_on('dep-with-variants', when='@develop')