Do not fail on unknown platform tags and just print a warning

python/private/whl_target_platforms.bzl

@@ -78,8 +78,11 @@ _CPU_ALIASES = {
     "aarch64": "aarch64",
     "arm64": "aarch64",
     "ppc": "ppc",
+    "ppc64": "ppc",
     "ppc64le": "ppc",
     "s390x": "s390x",
+    "armv6l": "arm",
+    "armv7l": "arm",
 }  # buildifier: disable=unsorted-dict-items
 
 _OS_PREFIXES = {
@@ -249,7 +252,8 @@ def whl_target_platforms(platform_tag, abi_tag = ""):
                 for cpu in cpus
             ]
 
-    fail("unknown platform_tag os: {}".format(platform_tag))
+    print("WARNING: ignoring unknown platform_tag os: {}".format(platform_tag))  # buildifier: disable=print
+    return []
 
 def _cpu_from_tag(tag):
     candidate = [
@@ -262,7 +266,14 @@ def _cpu_from_tag(tag):
 
     if tag == "win32":
         return ["x86_32"]
-    elif tag.endswith("universal2") and tag.startswith("macosx"):
-        return ["x86_64", "aarch64"]
-    else:
-        fail("Unrecognized tag: '{}': cannot determine CPU".format(tag))
+    elif tag == "win_ia64":
+        return []
+    elif tag.startswith("macosx"):
+        if tag.endswith("universal2"):
+            return ["x86_64", "aarch64"]
+        elif tag.endswith("universal"):
+            return ["x86_64", "aarch64"]
+        elif tag.endswith("intel"):
+            return ["x86_32"]
+
+    return []

tests/private/whl_target_platforms/whl_target_platforms_tests.bzl

@@ -72,10 +72,62 @@ def _test_with_abi(env):
 
 _tests.append(_test_with_abi)
 
+def _can_parse_existing_tags(env):
+    examples = {
+        "linux_armv6l": 1,
+        "linux_armv7l": 1,
+        "macosx_11_12_arm64": 1,
+        "macosx_11_12_i386": 1,
+        "macosx_11_12_intel": 1,
+        "macosx_11_12_universal": 2,
+        "macosx_11_12_universal2": 2,
+        "macosx_11_12_x86_64": 1,
+        "manylinux1_i686": 1,
+        "manylinux1_x86_64": 1,
+        "manylinux2010_i686": 1,
+        "manylinux2010_x86_64": 1,
+        "manylinux2014_aarch64": 1,
+        "manylinux2014_armv7l": 1,
+        "manylinux2014_i686": 1,
+        "manylinux2014_ppc64": 1,
+        "manylinux2014_ppc64le": 1,
+        "manylinux2014_s390x": 1,
+        "manylinux2014_x86_64": 1,
+        "manylinux_11_12_aarch64": 1,
+        "manylinux_11_12_armv7l": 1,
+        "manylinux_11_12_i686": 1,
+        "manylinux_11_12_ppc64": 1,
+        "manylinux_11_12_ppc64le": 1,
+        "manylinux_11_12_s390x": 1,
+        "manylinux_11_12_x86_64": 1,
+        "manylinux_1_2_aarch64": 1,
+        "manylinux_1_2_x86_64": 1,
+        "musllinux_11_12_aarch64": 1,
+        "musllinux_11_12_armv7l": 1,
+        "musllinux_11_12_i686": 1,
+        "musllinux_11_12_ppc64le": 1,
+        "musllinux_11_12_s390x": 1,
+        "musllinux_11_12_x86_64": 1,
+        "win32": 1,
+        "win_amd64": 1,
+        "win_arm64": 1,
+        "win_ia64": 0,
+    }
+
+    for major_version in [2, 10, 13]:
+        for minor_version in [0, 1, 2, 10, 45]:
+            for give, want_size in examples.items():
+                give = give.replace("_11_", "_{}_".format(major_version))
+                give = give.replace("_12_", "_{}_".format(minor_version))
+                got = whl_target_platforms(give)
+                env.expect.that_str("{}: {}".format(give, len(got))).equals("{}: {}".format(give, want_size))
+
+_tests.append(_can_parse_existing_tags)
+
 def whl_target_platforms_test_suite(name):
-    """Create the test suite.
+    """create the test suite.
 
-    Args:
+    args:
         name: the name of the test suite
     """
     test_suite(name = name, basic_tests = _tests)