Define components for GitVersion provenance

Adding binary provenance requires we track the commit.
Typically this has been an optional form for the encompassing git ref.
Moving towards always defining a commit means we need to have space
to store a user requested ref that will then be paired with a commit
sha.

lib/spack/spack/test/versions.py

@@ -810,6 +810,35 @@ def test_version_list_with_range_and_concrete_version_is_not_concrete():
     v = VersionList([Version("3.1"), VersionRange(Version("3.1.1"), Version("3.1.2"))])
     assert not v.concrete
 
+@pytest.mark.parametrize(
+    "pre_equal, post_equal", (
+    ("foo", "develop"),
+    ("a"*40, "develop"),
+    ("a"*40, None),
+    ("v1.2.0", "1.2.0")
+    )
+)
+def test_git_versions_store_ref_requests(pre_equal, post_equal):
+    """
+    User requested ref's should be known on creation
+    Commit and standard version may not be known until concretization
+    To be concrete a GitVersion must have a commit and standard version
+    """
+    if post_equal:
+        vstring = f"git.{pre_equal}={post_equal}"
+    else:
+        vstring = pre_equal
+
+    v = Version(vstring)
+
+    assert isinstance(v, GitVersion)
+    assert v.requested_ref == pre_equal
+
+    if post_equal:
+        assert v.std_version == Version(post_equal)
+
+    if v.is_commit:
+        assert v.requested_ref == v.commit_sha
 
 @pytest.mark.parametrize(
     "vstring, eq_vstring, is_commit",

lib/spack/spack/version/version_types.py

@@ -551,6 +551,11 @@ class GitVersion(ConcreteVersion):
     __slots__ = ["ref", "has_git_prefix", "is_commit", "_ref_lookup", "_ref_version"]
 
     def __init__(self, string: str):
+        # WIP refactor
+        self.requested_ref: Optional[String] = None
+        self.commit_sha: Optional[String] = None
+        self.std_version: Optional[StandardVersion] = None
+
         # An object that can lookup git refs to compare them to versions
         self._ref_lookup: Optional[AbstractRefLookup] = None
 
@@ -577,6 +582,11 @@ def __init__(self, string: str):
         # Used by fetcher
         self.is_commit: bool = len(self.ref) == 40 and bool(COMMIT_VERSION.match(self.ref))
 
+        self.requested_ref = self.ref
+        self.std_version = self._ref_version
+        if self.is_commit:
+            self.commit_sha = self.ref
+
     @property
     def ref_version(self) -> StandardVersion:
         # Return cached version if we have it