From a51f4b77d95a0bcba6776f710493dd9bad93ca3f Mon Sep 17 00:00:00 2001
From: Greg Becker <becker33@llnl.gov>
Date: Thu, 9 Mar 2023 16:46:47 -0800
Subject: [PATCH] reorder_flags: properly handle flags from concrete reused
 specs (#35951)

---
 lib/spack/spack/solver/asp.py      | 15 +++++++++++----
 lib/spack/spack/test/concretize.py | 12 ++++++++++++
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/lib/spack/spack/solver/asp.py b/lib/spack/spack/solver/asp.py
index 3537a5e2df..670dcf6ef9 100644
--- a/lib/spack/spack/solver/asp.py
+++ b/lib/spack/spack/solver/asp.py
@@ -1463,6 +1463,7 @@ class Head(object):
             node_compiler = fn.attr("node_compiler_set")
             node_compiler_version = fn.attr("node_compiler_version_set")
             node_flag = fn.attr("node_flag_set")
+            node_flag_source = fn.attr("node_flag_source")
             node_flag_propagate = fn.attr("node_flag_propagate")
             variant_propagate = fn.attr("variant_propagate")
 
@@ -1476,6 +1477,7 @@ class Body(object):
             node_compiler = fn.attr("node_compiler")
             node_compiler_version = fn.attr("node_compiler_version")
             node_flag = fn.attr("node_flag")
+            node_flag_source = fn.attr("node_flag_source")
             node_flag_propagate = fn.attr("node_flag_propagate")
             variant_propagate = fn.attr("variant_propagate")
 
@@ -1557,6 +1559,7 @@ class Body(object):
         for flag_type, flags in spec.compiler_flags.items():
             for flag in flags:
                 clauses.append(f.node_flag(spec.name, flag_type, flag))
+                clauses.append(f.node_flag_source(spec.name, flag_type, spec.name))
                 if not spec.concrete and flag.propagate is True:
                     clauses.append(f.node_flag_propagate(spec.name, flag_type))
 
@@ -2181,6 +2184,7 @@ def __init__(self, specs, hash_lookup=None):
         self._specs = {}
         self._result = None
         self._command_line_specs = specs
+        self._hash_specs = []
         self._flag_sources = collections.defaultdict(lambda: set())
         self._flag_compiler_defaults = set()
 
@@ -2191,6 +2195,7 @@ def __init__(self, specs, hash_lookup=None):
     def hash(self, pkg, h):
         if pkg not in self._specs:
             self._specs[pkg] = self._hash_lookup[h]
+        self._hash_specs.append(pkg)
 
     def node(self, pkg):
         if pkg not in self._specs:
@@ -2316,8 +2321,8 @@ def reorder_flags(self):
                     )
 
                     # add flags from each source, lowest to highest precedence
-                    for source_name in sorted_sources:
-                        source = cmd_specs[source_name]
+                    for name in sorted_sources:
+                        source = self._specs[name] if name in self._hash_specs else cmd_specs[name]
                         extend_flag_list(from_sources, source.compiler_flags.get(flag_type, []))
 
                 # compiler flags from compilers config are lowest precedence
@@ -2392,10 +2397,12 @@ def build_specs(self, function_tuples):
                     continue
 
                 # if we've already gotten a concrete spec for this pkg,
-                # do not bother calling actions on it.
+                # do not bother calling actions on it except for node_flag_source,
+                # since node_flag_source is tracking information not in the spec itself
                 spec = self._specs.get(pkg)
                 if spec and spec.concrete:
-                    continue
+                    if name != "node_flag_source":
+                        continue
 
             action(*args)
 
diff --git a/lib/spack/spack/test/concretize.py b/lib/spack/spack/test/concretize.py
index 11393ba8c3..621360e2b4 100644
--- a/lib/spack/spack/test/concretize.py
+++ b/lib/spack/spack/test/concretize.py
@@ -1274,6 +1274,18 @@ def test_reuse_installed_packages_when_package_def_changes(
         # Structure and package hash will be different without reuse
         assert root.dag_hash() != new_root_without_reuse.dag_hash()
 
+    def test_reuse_with_flags(self, mutable_database, mutable_config):
+        if spack.config.get("config:concretizer") == "original":
+            pytest.xfail("Original concretizer does not reuse")
+
+        spack.config.set("concretizer:reuse", True)
+        spec = Spec("a cflags=-g cxxflags=-g").concretized()
+        spack.store.db.add(spec, None)
+
+        testspec = Spec("a cflags=-g")
+        testspec.concretize()
+        assert testspec == spec
+
     @pytest.mark.regression("20784")
     def test_concretization_of_test_dependencies(self):
         # With clingo we emit dependency_conditions regardless of the type