Use conda.base.constants.KNOWN_SUBDIRS for setting up selectors

conda_build/metadata.py

@@ -21,6 +21,7 @@
 from conda_build.features import feature_list
 from conda_build.license_family import ensure_valid_license_family
 from conda_build.utils import (
+    DEFAULT_SUBDIRS,
     HashableDict,
     ensure_list,
     expand_globs,
@@ -29,7 +30,7 @@
     insert_variant_versions,
 )
 
-from .conda_interface import MatchSpec, envs_dirs, md5_file, non_x86_linux_machines
+from .conda_interface import MatchSpec, envs_dirs, md5_file
 
 try:
     import yaml
@@ -121,25 +122,36 @@ def get_selectors(config: Config) -> dict[str, bool]:
     # Remember to update the docs of any of this changes
     plat = config.host_subdir
     d = dict(
-        linux=plat.startswith("linux-"),
         linux32=bool(plat == "linux-32"),
         linux64=bool(plat == "linux-64"),
-        emscripten=plat.startswith("emscripten-"),
-        wasi=plat.startswith("wasi-"),
         arm=plat.startswith("linux-arm"),
-        osx=plat.startswith("osx-"),
         unix=plat.startswith(("linux-", "osx-", "emscripten-")),
-        win=plat.startswith("win-"),
         win32=bool(plat == "win-32"),
         win64=bool(plat == "win-64"),
-        x86=plat.endswith(("-32", "-64")),
-        x86_64=plat.endswith("-64"),
-        wasm32=bool(plat.endswith("-wasm32")),
         os=os,
         environ=os.environ,
         nomkl=bool(int(os.environ.get("FEATURE_NOMKL", False))),
     )
 
+    # Add the current platform to the list of subdirs to enable conda-build
+    # to bootstrap new platforms without a new conda release.
+    subdirs = list(DEFAULT_SUBDIRS) + [plat]
+
+    # filter out noarch and other weird subdirs
+    subdirs = [subdir for subdir in subdirs if "-" in subdir]
+
+    subdir_oses = {subdir.split("-")[0] for subdir in subdirs}
+    subdir_archs = {subdir.split("-")[1] for subdir in subdirs}
+
+    for subdir_os in subdir_oses:
+        d[subdir_os] = plat.startswith(f"{subdir_os}-")
+
+    for arch in subdir_archs:
+        arch_full = ARCH_MAP.get(arch, arch)
+        d[arch_full] = plat.endswith(f"-{arch}")
+        if arch == "32":
+            d["x86"] = plat.endswith(("-32", "-64"))
+
     defaults = variants.get_default_variant(config)
     py = config.variant.get("python", defaults["python"])
     # there are times when python comes in as a tuple
@@ -183,9 +195,6 @@ def get_selectors(config: Config) -> dict[str, bool]:
     d["lua"] = lua
     d["luajit"] = bool(lua[0] == "2")
 
-    for machine in non_x86_linux_machines:
-        d[machine] = bool(plat.endswith("-%s" % machine))
-
     for feature, value in feature_list:
         d[feature] = value
     d.update(os.environ)

conda_build/utils.py

@@ -67,6 +67,7 @@
 from glob import glob
 
 from conda.api import PackageCacheData  # noqa
+from conda.base.constants import KNOWN_SUBDIRS
 
 # NOQA because it is not used in this file.
 from conda_build.conda_interface import rm_rf as _rm_rf  # noqa
@@ -104,25 +105,7 @@
 mmap_PROT_READ = 0 if on_win else mmap.PROT_READ
 mmap_PROT_WRITE = 0 if on_win else mmap.PROT_WRITE
 
-DEFAULT_SUBDIRS = {
-    "emscripten-wasm32",
-    "wasi-wasm32",
-    "linux-64",
-    "linux-32",
-    "linux-s390x",
-    "linux-ppc64",
-    "linux-ppc64le",
-    "linux-armv6l",
-    "linux-armv7l",
-    "linux-aarch64",
-    "win-64",
-    "win-32",
-    "win-arm64",
-    "osx-64",
-    "osx-arm64",
-    "zos-z",
-    "noarch",
-}
+DEFAULT_SUBDIRS = set(KNOWN_SUBDIRS)
 
 RUN_EXPORTS_TYPES = {
     "weak",

docs/source/resources/define-metadata.rst

@@ -1928,10 +1928,10 @@ variables are booleans.
    * - osx
      - True if the platform is macOS.
    * - arm64
-     - True if the platform is macOS and the Python architecture
-       is arm64.
+     - True if the platform is either macOS or Windows and the
+       Python architecture is arm64.
    * - unix
-     - True if the platform is either macOS or Linux.
+     - True if the platform is either macOS or Linux or emscripten.
    * - win
      - True if the platform is Windows.
    * - win32
@@ -1965,6 +1965,11 @@ The use of the Python version selectors, `py27`, `py34`, etc. is discouraged in
 favor of the more general comparison operators.  Additional selectors in this
 series will not be added to conda-build.
 
+Note that for each subdir with OS and architecture that `conda` supports,
+two preprocessing selectors are created for the OS and the architecture separately
+except when the architecture is not a valid python expression (`*-32` and `*-64`
+in particular).
+
 Because the selector is any valid Python expression, complicated
 logic is possible:
 

news/5009-use-conda-known-subdirs

@@ -0,0 +1,24 @@
+### Enhancements
+
+* Use subdirs known to conda for selector definitions. (#5009)
+  This allows conda_build to support new architectures with just
+  a new version of conda. For new OSes, there are more information
+  needed for conda_build to work properly, including whether the
+  new OS is a UNIX-like platform, the shared library prefix, and
+  the binary archive format for the platform.
+
+### Bug fixes
+
+* <news item>
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>

tests/test_metadata.py

@@ -342,6 +342,7 @@ def test_yamlize_versions():
     "armv6l",
     "armv7l",
     "emscripten",
+    "freebsd",
     "linux",
     "linux32",
     "linux64",
@@ -358,6 +359,8 @@ def test_yamlize_versions():
     "win64",
     "x86",
     "x86_64",
+    "z",
+    "zos",
 )
 
 
@@ -369,7 +372,7 @@ def test_yamlize_versions():
     [
         ("emscripten-wasm32", {"unix", "emscripten", "wasm32"}),
         ("wasi-wasm32", {"wasi", "wasm32"}),
-        ("freebsd-64", {"x86", "x86_64"}),
+        ("freebsd-64", {"freebsd", "x86", "x86_64"}),
         ("linux-32", {"unix", "linux", "linux32", "x86"}),
         ("linux-64", {"unix", "linux", "linux64", "x86", "x86_64"}),
         ("linux-aarch64", {"unix", "linux", "aarch64"}),
@@ -384,7 +387,7 @@ def test_yamlize_versions():
         ("win-32", {"win", "win32", "x86"}),
         ("win-64", {"win", "win64", "x86", "x86_64"}),
         ("win-arm64", {"win", "arm64"}),
-        ("zos-z", {}),
+        ("zos-z", {"zos", "z"}),
     ],
 )
 @pytest.mark.parametrize("nomkl", [0, 1])