Null variant labels

tests/artifacts/test-package/dist/test_package-0-variants.json

@@ -20,7 +20,7 @@
         }
     },
     "variants": {
-        "00000000": {},
+        "null": {},
         "5d8be4b9": {
             "installable_plugin": {
                 "feat1": [

tests/artifacts/variant_json_files/dummy_project-1.0.0-variants.json

@@ -75,7 +75,7 @@
                 ]
             }
         },
-        "00000000": {},
+        "null": {},
         "3f7188c1": {
             "fictional_hw": {
                 "architecture": [

tests/artifacts/variant_json_files/sandbox_project-1.0.0-variants.json

@@ -23,7 +23,7 @@
         }
     },
     "variants": {
-        "00000000": {},
+        "null": {},
         "38ea48ce": {
             "fictional_hw": {
                 "architecture": [
@@ -69,4 +69,4 @@
             }
         }
     }
-}
+}

tests/commands/test_analyze_wheel.py

@@ -3,7 +3,7 @@
 from typing import TYPE_CHECKING
 
 from variantlib.commands.main import main
-from variantlib.constants import NULL_VARIANT_HASH
+from variantlib.constants import NULL_VARIANT_LABEL
 
 if TYPE_CHECKING:
     import pytest
@@ -34,13 +34,13 @@ def test_analyze_wheel_null_variant(
             "analyze-wheel",
             "-i",
             "tests/artifacts/test-package/dist/test_package-0-py3-none-any-"
-            f"{NULL_VARIANT_HASH}.whl",
+            f"{NULL_VARIANT_LABEL}.whl",
         ]
     )
     assert (
         capsys.readouterr().out
         == f"""\
-############################## Variant: `{NULL_VARIANT_HASH}` \
+############################## Variant: `{NULL_VARIANT_LABEL}` \
 #############################
 ################################################################################
 """

tests/commands/test_generate_index_json.py

@@ -6,7 +6,7 @@
 from typing import TYPE_CHECKING
 
 from variantlib.commands.main import main
-from variantlib.constants import NULL_VARIANT_HASH
+from variantlib.constants import NULL_VARIANT_LABEL
 from variantlib.constants import VARIANT_INFO_DEFAULT_PRIO_KEY
 from variantlib.constants import VARIANT_INFO_NAMESPACE_KEY
 from variantlib.constants import VARIANT_INFO_PROVIDER_DATA_KEY
@@ -25,7 +25,7 @@ def test_generate_index_json(
 ) -> None:
     filenames = [
         "test_package-0-py3-none-any.whl",
-        f"test_package-0-py3-none-any-{NULL_VARIANT_HASH}.whl",
+        f"test_package-0-py3-none-any-{NULL_VARIANT_LABEL}.whl",
         "test_package-0-py3-none-any-5d8be4b9.whl",
     ]
     artifact_dir = Path("tests/artifacts/test-package/dist")
@@ -51,7 +51,7 @@ def test_generate_index_json(
             },
         },
         VARIANTS_JSON_VARIANT_DATA_KEY: {
-            NULL_VARIANT_HASH: {},
+            NULL_VARIANT_LABEL: {},
             "5d8be4b9": {
                 "installable_plugin": {
                     "feat1": ["val1c"],

tests/commands/test_get_variant_hash.py

@@ -1,17 +1,18 @@
 from __future__ import annotations
 
+import hashlib
 from itertools import chain
 
 import pytest
 
 from variantlib.commands.main import main
-from variantlib.constants import NULL_VARIANT_HASH
+from variantlib.constants import VARIANT_HASH_LEN
 
 
 @pytest.mark.parametrize(
     ("properties", "expected"),
     [
-        ([], NULL_VARIANT_HASH),
+        ([], hashlib.sha256(b"").hexdigest()[:VARIANT_HASH_LEN]),
         (["a::b::c"], "01a9783a"),
         (["d::e::f"], "41665eee"),
         (["a::b::c", "d::e::f"], "eb9a66a7"),

tests/commands/test_make_variant.py

@@ -7,7 +7,7 @@
 
 from tests.utils import assert_zips_equal
 from variantlib.commands.main import main
-from variantlib.constants import NULL_VARIANT_HASH
+from variantlib.constants import NULL_VARIANT_LABEL
 
 if TYPE_CHECKING:
     from pathlib import Path
@@ -37,7 +37,7 @@ def mocked_plugin_reqs(
     ("label", "properties"),
     [
         # Null Variant
-        (NULL_VARIANT_HASH, None),
+        (NULL_VARIANT_LABEL, None),
         # Variant 1
         (
             "5d8be4b9",
@@ -86,7 +86,7 @@ def test_make_variant(
             itertools.chain.from_iterable(["-p", vprop] for vprop in properties)
         )
 
-    if len(label) != 8:
+    if len(label) != 8 and label != "null":
         cmd_args.append(f"--variant-label={label}")
 
     main([*cmd_args])
@@ -112,9 +112,13 @@ def test_make_variant(
             ["--property=x::y::z", "--variant-label=123456789"],
             "error: invalid variant label",
         ),
+        (
+            ["--property=x::y::z", "--variant-label=null"],
+            "error: invalid variant label",
+        ),
         (
             ["--null-variant", "--variant-label=null"],
-            "error: --variant-label cannot be usedwith --null-variant",
+            "error: --variant-label cannot be used with --null-variant",
         ),
     ],
 )

tests/commands/test_unmake_variant.py

@@ -6,13 +6,13 @@
 
 from tests.utils import assert_zips_equal
 from variantlib.commands.main import main
-from variantlib.constants import NULL_VARIANT_HASH
+from variantlib.constants import NULL_VARIANT_LABEL
 
 
 @pytest.mark.parametrize(
     "filename",
     [
-        f"test_package-0-py3-none-any-{NULL_VARIANT_HASH}.whl",
+        f"test_package-0-py3-none-any-{NULL_VARIANT_LABEL}.whl",
         "test_package-0-py3-none-any-5d8be4b9.whl",
         "test_package-0-py3-none-any-60567bd9.whl",
         "test_package-0-py3-none-any-fbe82642.whl",

tests/models/test_variant.py

@@ -7,7 +7,6 @@
 from hypothesis import given
 from hypothesis import strategies as st
 
-from variantlib.constants import NULL_VARIANT_HASH
 from variantlib.constants import VALIDATION_FEATURE_NAME_REGEX
 from variantlib.constants import VALIDATION_NAMESPACE_REGEX
 from variantlib.constants import VALIDATION_VALUE_REGEX
@@ -238,7 +237,7 @@ def test_variantprop_sorting() -> None:
 def test_null_variant() -> None:
     vdesc = VariantDescription()
     assert vdesc.properties == []
-    assert vdesc.hexdigest == NULL_VARIANT_HASH
+    assert vdesc.hexdigest == hashlib.sha256(b"").hexdigest()[:VARIANT_HASH_LEN]
 
 
 def test_variantdescription_initialization() -> None:

tests/test_api.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import json
+import re
 import string
 from collections.abc import Generator
 from typing import TYPE_CHECKING
@@ -24,10 +25,11 @@
 from variantlib.api import VariantValidationResult
 from variantlib.api import check_variant_supported
 from variantlib.api import get_variant_environment_dict
+from variantlib.api import get_variant_label
 from variantlib.api import get_variants_by_priority
 from variantlib.api import make_variant_dist_info
 from variantlib.api import validate_variant
-from variantlib.constants import NULL_VARIANT_HASH
+from variantlib.constants import NULL_VARIANT_LABEL
 from variantlib.constants import PYPROJECT_TOML_TOP_KEY
 from variantlib.constants import VALIDATION_FEATURE_NAME_REGEX
 from variantlib.constants import VALIDATION_NAMESPACE_REGEX
@@ -130,10 +132,10 @@ def test_get_variants_by_priority_roundtrip(
         },
         VARIANTS_JSON_VARIANT_DATA_KEY: {
             f"foo{vdesc.hexdigest[:4]}"
-            if custom_labels and vdesc.hexdigest != NULL_VARIANT_HASH
-            else vdesc.hexdigest: vdesc.to_dict()
+            if custom_labels and not vdesc.is_null_variant()
+            else get_variant_label(vdesc): vdesc.to_dict()
             for vdesc in combinations
-            if explicit_null or vdesc.hexdigest != NULL_VARIANT_HASH
+            if explicit_null or not vdesc.is_null_variant()
         },
     }
 
@@ -146,8 +148,8 @@ def test_get_variants_by_priority_roundtrip(
 
     assert get_variants_by_priority(variants_json=typed_variants_json) == [
         f"foo{vdesc.hexdigest[:4]}"
-        if custom_labels and vdesc.hexdigest != NULL_VARIANT_HASH
-        else vdesc.hexdigest
+        if custom_labels and not vdesc.is_null_variant()
+        else get_variant_label(vdesc)
         for vdesc in combinations
     ]
 
@@ -220,7 +222,7 @@ def get_or_skip_combinations() -> Generator[VariantDescription]:
 
     variants_json = {
         VARIANTS_JSON_VARIANT_DATA_KEY: {
-            vdesc.hexdigest: vdesc.to_dict() for vdesc in combinations
+            get_variant_label(vdesc): vdesc.to_dict() for vdesc in combinations
         }
     }
 
@@ -234,7 +236,7 @@ def get_or_skip_combinations() -> Generator[VariantDescription]:
     ).return_value = {provider_cfg.namespace: provider_cfg for provider_cfg in configs}
 
     assert get_variants_by_priority(variants_json=typed_variants_json) == [
-        vdesc.hexdigest for vdesc in combinations
+        get_variant_label(vdesc) for vdesc in combinations
     ]
 
 
@@ -550,24 +552,114 @@ def test_get_variant_environment_dict() -> None:
 
 def test_make_variant_dist_info_invalid_label():
     with pytest.raises(
-        ValidationError, match=r"Variant label cannot be specified for the null variant"
+        ValidationError,
+        match=rf"Null variant must always use {NULL_VARIANT_LABEL!r} label",
     ):
         make_variant_dist_info(VariantDescription([]), variant_label="foo")
     with pytest.raises(
         ValidationError,
-        match=rf"{NULL_VARIANT_HASH} label can be used only for the null variant",
+        match=rf"{NULL_VARIANT_LABEL!r} label can be used only for the null variant",
     ):
         make_variant_dist_info(
             VariantDescription([VariantProperty("a", "b", "c")]),
-            variant_label=NULL_VARIANT_HASH,
+            variant_label=NULL_VARIANT_LABEL,
         )
-    with pytest.raises(ValidationError, match=r"Invalid variant label: foo/bar"):
+    with pytest.raises(
+        ValidationError,
+        match=re.escape(
+            "Invalid variant label: 'foo/bar' (must be up to 8 alphanumeric characters)"
+        ),
+    ):
         make_variant_dist_info(
             VariantDescription([VariantProperty("a", "b", "c")]),
             variant_label="foo/bar",
         )
-    with pytest.raises(ValidationError, match=r"Invalid variant label: 123456789"):
+    with pytest.raises(
+        ValidationError,
+        match=re.escape(
+            "Invalid variant label: '123456789' (must be up to 8 alphanumeric "
+            "characters)"
+        ),
+    ):
         make_variant_dist_info(
             VariantDescription([VariantProperty("a", "b", "c")]),
             variant_label="123456789",
         )
+
+
+def test_get_variant_label() -> None:
+    assert get_variant_label(VariantDescription()) == NULL_VARIANT_LABEL
+    assert (
+        get_variant_label(VariantDescription(), NULL_VARIANT_LABEL)
+        == NULL_VARIANT_LABEL
+    )
+
+    assert (
+        get_variant_label(VariantDescription([VariantProperty("a", "b", "c")]))
+        == "01a9783a"
+    )
+    assert (
+        get_variant_label(
+            VariantDescription(
+                [VariantProperty("a", "b", "c"), VariantProperty("d", "e", "f")]
+            )
+        )
+        == "eb9a66a7"
+    )
+    assert (
+        get_variant_label(
+            VariantDescription(
+                [VariantProperty("d", "e", "f"), VariantProperty("a", "b", "c")]
+            )
+        )
+        == "eb9a66a7"
+    )
+
+    assert (
+        get_variant_label(VariantDescription([VariantProperty("a", "b", "c")]), "foo")
+        == "foo"
+    )
+    assert (
+        get_variant_label(
+            VariantDescription(
+                [VariantProperty("a", "b", "c"), VariantProperty("d", "e", "f")]
+            ),
+            "foo",
+        )
+        == "foo"
+    )
+
+    with pytest.raises(
+        ValidationError,
+        match=rf"Null variant must always use {NULL_VARIANT_LABEL!r} label",
+    ):
+        get_variant_label(VariantDescription([]), "foo")
+    with pytest.raises(
+        ValidationError,
+        match=rf"{NULL_VARIANT_LABEL!r} label can be used only for the null variant",
+    ):
+        get_variant_label(
+            VariantDescription([VariantProperty("a", "b", "c")]),
+            NULL_VARIANT_LABEL,
+        )
+    with pytest.raises(
+        ValidationError,
+        match=re.escape(
+            "Invalid variant label: 'foo/bar' (must be up to 8 alphanumeric characters)"
+        ),
+    ):
+        get_variant_label(
+            VariantDescription([VariantProperty("a", "b", "c")]),
+            "foo/bar",
+        )
+    with pytest.raises(
+        ValidationError,
+        match=re.escape(
+            "Invalid variant label: '123456789' (must be up to 8 alphanumeric "
+            "characters)"
+        ),
+    ):
+        get_variant_label(
+            VariantDescription([VariantProperty("a", "b", "c")]),
+            "123456789",
+        )