Fix missing __unix virtual package in 22.11 (conda#12148)

* Add test for default virtual system packages

* Restore default virtual package specs as in 22.9.0

* Add news/12148-restore-default-virtual-packages

* Properly skip virtual packages with no name

* Avoid empty -> "0" build string for __archspec

Overlooked before; this just restores <22.11.0 behavior.

conda/core/index.py

@@ -145,12 +145,12 @@ def _supplement_index_with_cache(index):
             index[pcrec] = pcrec
 
 
-def _make_virtual_package(name, version=None, build_string='0'):
+def _make_virtual_package(name, version=None, build_string=None):
     return PackageRecord(
             package_type=PackageType.VIRTUAL_SYSTEM,
             name=name,
             version=version or '0',
-            build_string=build_string,
+            build_string=build_string or '0',
             channel='@',
             subdir=context.subdir,
             md5="12345678901234567890123456789012",
@@ -174,6 +174,8 @@ def _supplement_index_with_system(index):
     registered_names = []
     packages = context.plugin_manager.get_hook_results("virtual_packages")
     for package in packages:
+        if package.name is None:
+            continue
         if package.name in registered_names:
             raise PluginError(
                 "Conflicting virtual package entries found for the "
@@ -184,10 +186,8 @@ def _supplement_index_with_system(index):
             )
         registered_names.append(package.name)
 
-        rec = _make_virtual_package(f"__{package.name}", package.version)
-
-        if package.version is not None:
-            index[rec] = rec
+        rec = _make_virtual_package(f"__{package.name}", package.version, package.build)
+        index[rec] = rec
 
 
 def get_archspec_name():

conda/plugins/hookspec.py

@@ -96,6 +96,7 @@ def conda_virtual_packages():
                 yield plugins.CondaVirtualPackage(
                     name="my_custom_os",
                     version="1.2.3",
+                    build="x86_64",
                 )
 
         """

conda/plugins/types.py

@@ -29,10 +29,12 @@ class CondaVirtualPackage(NamedTuple):
 
     :param name: Virtual package name (e.g., ``my_custom_os``).
     :param version: Virtual package version (e.g., ``1.2.3``).
+    :param version: Virtual package build string (e.g., ``x86_64``).
     """
 
     name: str
     version: str | None
+    build: str | None
 
 
 class CondaSolver(NamedTuple):

conda/plugins/virtual_packages/archspec.py

@@ -7,4 +7,6 @@
 def conda_virtual_packages():
     from ...core.index import get_archspec_name
 
-    yield CondaVirtualPackage("archspec", get_archspec_name())
+    archspec_name = get_archspec_name()
+    if archspec_name:
+        yield CondaVirtualPackage("archspec", "1", archspec_name)

conda/plugins/virtual_packages/cuda.py

@@ -84,4 +84,6 @@ def cached_cuda_version():
 
 @hookimpl
 def conda_virtual_packages():
-    yield CondaVirtualPackage("cuda", cached_cuda_version())
+    cuda_version = cached_cuda_version()
+    if cuda_version is not None:
+        yield CondaVirtualPackage("cuda", cuda_version, None)

conda/plugins/virtual_packages/linux.py

@@ -13,7 +13,7 @@ def conda_virtual_packages():
     if platform.system() != "Linux":
         return
 
-    yield CondaVirtualPackage("unix", None)
+    yield CondaVirtualPackage("unix", None, None)
 
     # By convention, the kernel release string should be three or four
     # numeric components, separated by dots, followed by vendor-specific
@@ -23,11 +23,11 @@ def conda_virtual_packages():
     # development (`-rcN`) kernels, but that can be a TODO for later.
     dist_version = os.environ.get("CONDA_OVERRIDE_LINUX", platform.release())
     m = re.match(r"\d+\.\d+(\.\d+)?(\.\d+)?", dist_version)
-    yield CondaVirtualPackage("linux", m.group() if m else "0")
+    yield CondaVirtualPackage("linux", m.group() if m else "0", None)
 
     libc_family, libc_version = linux_get_libc_version()
     if not (libc_family and libc_version):
         # Default to glibc when using CONDA_SUBDIR var
         libc_family = "glibc"
     libc_version = os.getenv(f"CONDA_OVERRIDE_{libc_family.upper()}", libc_version)
-    yield CondaVirtualPackage(libc_family, libc_version)
+    yield CondaVirtualPackage(libc_family, libc_version, None)

conda/plugins/virtual_packages/osx.py

@@ -11,7 +11,7 @@ def conda_virtual_packages():
     if platform.system() != "Darwin":
         return
 
-    yield CondaVirtualPackage("unix", None)
+    yield CondaVirtualPackage("unix", None, None)
 
     dist_version = os.environ.get("CONDA_OVERRIDE_OSX", platform.mac_ver()[0])
-    yield CondaVirtualPackage("osx", dist_version)
+    yield CondaVirtualPackage("osx", dist_version, None)

conda/plugins/virtual_packages/windows.py

@@ -11,4 +11,4 @@ def conda_virtual_packages():
     if platform.system() != "Windows":
         return
 
-    yield CondaVirtualPackage("win", None)
+    yield CondaVirtualPackage("win", None, None)

news/12148-restore-default-virtual-packages

@@ -0,0 +1,21 @@
+### Enhancements
+
+* <news item>
+
+### Bug fixes
+
+* Restore default virtual package specs as in 22.9.0 (#12148)
+  - re-add `__unix`/`__win` packages
+  - restore `__archspec` version/build string composition
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>

tests/core/test_index.py

@@ -10,7 +10,7 @@
 import pytest
 
 from conda.base.constants import DEFAULT_CHANNELS
-from conda.base.context import context, Context, conda_tests_ctxt_mgmt_def_pol
+from conda.base.context import context, Context, conda_tests_ctxt_mgmt_def_pol, non_x86_machines
 from conda.common.compat import on_win, on_mac, on_linux
 from conda.common.io import env_vars
 from conda.core.index import check_allowlist, get_index, get_reduced_index, _supplement_index_with_system
@@ -42,6 +42,36 @@ def test_check_allowlist():
     check_allowlist(("conda-canary",))
 
 
+def test_supplement_index_with_system():
+    index = {}
+    _supplement_index_with_system(index)
+
+    has_virtual_pkgs = {
+        rec.name
+        for rec in index
+        if rec.package_type == PackageType.VIRTUAL_SYSTEM
+    }.issuperset
+    if on_win:
+        assert has_virtual_pkgs({"__win"})
+    elif on_mac:
+        assert has_virtual_pkgs({"__osx", "__unix"})
+    elif on_linux:
+        assert has_virtual_pkgs({"__glibc", "__linux", "__unix"})
+
+
+@pytest.mark.skipif(
+    context.subdir.split("-", 1)[1] not in {"32", "64", *non_x86_machines},
+    reason=f"archspec not available for subdir {context.subdir}",
+)
+def test_supplement_index_with_system_archspec():
+    index = {}
+    _supplement_index_with_system(index)
+    assert any(
+        rec.package_type == PackageType.VIRTUAL_SYSTEM and rec.name == "__archspec"
+        for rec in index
+    )
+
+
 def test_supplement_index_with_system_cuda(clear_cuda_version):
     index = {}
     with env_vars({'CONDA_OVERRIDE_CUDA': '3.2'}):

tests/plugins/test_manager.py

@@ -65,7 +65,7 @@ def test_get_hook_results(plugin_manager):
     class SecondArchspec:
         @plugins.hookimpl
         def conda_virtual_packages():
-            yield plugins.CondaVirtualPackage("archspec", "")
+            yield plugins.CondaVirtualPackage("archspec", "", None)
 
     plugin_manager.register(SecondArchspec)
     with pytest.raises(

tests/plugins/test_virtual_packages.py

@@ -20,14 +20,17 @@ def conda_virtual_packages(self):
         yield CondaVirtualPackage(
             name="abc",
             version="123",
+            build=None,
         )
         yield CondaVirtualPackage(
             name="def",
             version="456",
+            build=None,
         )
         yield CondaVirtualPackage(
             name="ghi",
             version="789",
+            build="xyz",
         )
 
 
@@ -52,6 +55,7 @@ def test_invoked(plugin):
     assert packages["__abc"].version == "123"
     assert packages["__def"].version == "456"
     assert packages["__ghi"].version == "789"
+    assert packages["__ghi"].build == "xyz"
 
 
 def test_duplicated(plugin_manager):