diff --git a/lib/spack/spack/package_base.py b/lib/spack/spack/package_base.py
index a02c73f7cc6..d70fb6ed98d 100644
--- a/lib/spack/spack/package_base.py
+++ b/lib/spack/spack/package_base.py
@@ -1012,7 +1012,7 @@ def needs_commit(cls, version) -> bool:
 
         ver_attrs = cls.versions.get(version)
         if ver_attrs:
-            return bool(ver_attrs.get("tag") or ver_attrs.get("branch"))
+            return bool(ver_attrs.get("commit") or ver_attrs.get("tag") or ver_attrs.get("branch"))
 
         return False
 
diff --git a/lib/spack/spack/solver/asp.py b/lib/spack/spack/solver/asp.py
index e9f90ed1136..25653c9f86b 100644
--- a/lib/spack/spack/solver/asp.py
+++ b/lib/spack/spack/solver/asp.py
@@ -1596,9 +1596,11 @@ def key_fn(version):
                     ),
                 )
             )
-            if pkg.needs_commit(declared_version.version):
-                commit = pkg.version_or_package_attr("commit", declared_version.version, "")
-                self.git_commit_versions[pkg.name][declared_version.version] = commit
+
+        for v in self.possible_versions[pkg.name]:
+            if pkg.needs_commit(v):
+                commit = pkg.version_or_package_attr("commit", v, "")
+                self.git_commit_versions[pkg.name][v] = commit
 
         # Declare deprecated versions for this package, if any
         deprecated = self.deprecated_versions[pkg.name]
@@ -2908,10 +2910,11 @@ def define_version_constraints(self):
             for v in versions:
                 if v in self.git_commit_versions[pkg_name]:
                     sha = self.git_commit_versions[pkg_name].get(v)
-                    self.gen.fact(fn.pkg_fact(pkg_name, fn.version_needs_commit(v)))
                     if sha:
                         self.gen.fact(fn.pkg_fact(pkg_name, fn.version_has_commit(v, sha)))
-            self.gen.newline()
+                    else:
+                        self.gen.fact(fn.pkg_fact(pkg_name, fn.version_needs_commit(v)))
+        self.gen.newline()
 
         for pkg_name, versions in sorted(self.version_constraints):
             # generate facts for each package constraint and the version
@@ -3109,8 +3112,18 @@ def setup(
             commit = spec.variants.get("commit")
             version = spec.versions.concrete_range_as_version
             if not version and commit:
-                version = max(spack.repo.PATH.get_pkg_class(spec.fullname).versions.keys())
-                spec.versions = spack.version.VersionList([version])
+                # look for a matching commit in versions otherwise default to max infinity version
+                versions = spack.repo.PATH.get_pkg_class(spec.fullname).versions
+                match = None
+                for v, data in versions.items():
+                    if data.get("commit") == commit.value[0]:
+                        match = v
+                        break
+                if match:
+                    spec.versions = spack.version.VersionList([match])
+                else:
+                    version = max(versions.keys())
+                    spec.versions = spack.version.VersionList([version])
 
 
         self.gen = ProblemInstanceBuilder()
diff --git a/lib/spack/spack/solver/concretize.lp b/lib/spack/spack/solver/concretize.lp
index 0906a7e4cc4..0f2b7a94f16 100644
--- a/lib/spack/spack/solver/concretize.lp
+++ b/lib/spack/spack/solver/concretize.lp
@@ -333,20 +333,26 @@ attr("node_version_satisfies", node(ID, Package), Constraint)
   :- attr("version", node(ID, Package), Version),
      pkg_fact(Package, version_satisfies(Constraint, Version)).
 
+% if a version needs a commit or has one it can use the commit variant
+can_accept_commit(Package, Version) :- pkg_fact(Package, version_needs_commit(Version)).
+can_accept_commit(Package, Version) :- pkg_fact(Package, version_has_commit(Version, _)).
+
 % Specs with a commit variant can't use versions that don't need commits
-error(10, "Cannot use commit variant with '{0}@{1}'", Package, Version)
+error(10, "Cannot use commit variant with '{0}@={1}'", Package, Version)
   :- attr("version", node(ID, Package), Version),
-     not pkg_fact(Package, version_needs_commit(Version)),
+     not can_accept_commit(Package, Version),
      attr("variant_value", node(ID, Package), "commit", _).
 
-% Versions with commits require a matching commit variant
-  :- attr("version", node(ID, Packate), Version),
-     pkg_fact(Package, version_has_commit(Version, Sha)),
-     not attr("variant_value", node(ID, Package), "commit", Sha).
+error(10, "Commit '{0}' must match package.py value '{1}' for '{2}@={3}'", Vsha, Psha, Package, Version)
+  :- attr("version", node(ID, Package), Version),
+     attr("variant_value", node(ID, Package), "commit", Vsha),
+     pkg_fact(Package, version_has_commit(Version, Psha)),
+     Vsha != Psha.
 
 #defined version_satisfies/3.
 #defined deprecated_versions_not_allowed/0.
 #defined deprecated_version/2.
+#defined can_accept_commit/2.
 
 %-----------------------------------------------------------------------------
 % Spec conditions and imposed constraints
diff --git a/lib/spack/spack/spec.py b/lib/spack/spack/spec.py
index fe7526ae96d..ce2542df669 100644
--- a/lib/spack/spack/spec.py
+++ b/lib/spack/spack/spec.py
@@ -2673,7 +2673,7 @@ def name_and_dependency_types(s: str) -> Tuple[str, dt.DepFlag]:
                 return name, depflag
 
             def spec_and_dependency_types(
-                s: Union[Spec, Tuple[Spec, str]],
+                s: Union[Spec, Tuple[Spec, str]]
             ) -> Tuple[Spec, dt.DepFlag]:
                 """Given a non-string key in the literal, extracts the spec
                 and its dependency types.