Disallow features from specifying whether they are enabled by default or not.

BEGIN_PUBLIC
Disallow features from specifying whether they are enabled by default or not.

Such a decision shouldn't be made by the feature, but instead by the toolchain author.
END_PUBLIC

PiperOrigin-RevId: 658621275
Change-Id: I4dae8ee1acc349a0ff6f09e6cf68e15fdc481a48

cc/toolchains/feature.bzl

@@ -65,7 +65,9 @@ def _cc_feature_impl(ctx):
     feature = FeatureInfo(
         label = ctx.label,
         name = name,
-        enabled = ctx.attr.enabled,
+        # Unused field, but leave it just in case we want to reuse it in the
+        # future.
+        enabled = False,
         args = collect_args_lists(ctx.attr.args, ctx.label),
         implies = collect_features(ctx.attr.implies),
         requires_any_of = tuple(collect_provider(
@@ -120,10 +122,6 @@ Example:
     )
 """,
         ),
-        "enabled": attr.bool(
-            mandatory = True,
-            doc = """Whether or not this feature is enabled by default.""",
-        ),
         "args": attr.label_list(
             doc = """Args that, when expanded, implement this feature.""",
             providers = [ArgsListInfo],
@@ -137,7 +135,8 @@ deemed compatible and may be enabled.
 
 Note: Even if `cc_feature.requires_any_of` is satisfied, a feature is not
 enabled unless another mechanism (e.g. command-line flags, `cc_feature.implies`,
-`cc_feature.enabled`) signals that the feature should actually be enabled.
+`cc_toolchain_config.enabled_features`) signals that the feature should actually
+be enabled.
 """,
             providers = [FeatureSetInfo],
         ),
@@ -159,8 +158,7 @@ It can be either:
     `mutually_exclusive = [":category"]` are mutually exclusive with each other.
 
 If this feature has a side-effect of implementing another feature, it can be
-useful to list that feature here to ensure they aren't enabled at the
+useful to list that feature here to ensure they aren't enabled at the same time.
-same time.
 """,
         ),
         "overrides": attr.label(
@@ -224,7 +222,6 @@ Examples:
     # A feature that can be easily toggled to optimize for size
     cc_feature(
         name = "optimize_for_size",
-        enabled = False,
         feature_name = "optimize_for_size",
         args = [":optimize_for_size_args"],
     )
@@ -235,7 +232,6 @@ Examples:
     #    https://bazel.build/docs/cc-toolchain-config-reference#wellknown-features
     cc_feature(
         name = "supports_pic",
-        enabled = True,
         overrides = "//cc/toolchains/features:supports_pic
     )
 """,

tests/rule_based_toolchain/features/BUILD

@@ -20,7 +20,6 @@ util.helper_target(
     cc_feature,
     name = "simple",
     args = [":c_compile"],
-    enabled = False,
     feature_name = "feature_name",
     visibility = ["//tests/rule_based_toolchain:__subpackages__"],
 )
@@ -29,7 +28,6 @@ util.helper_target(
     cc_feature,
     name = "simple2",
     args = [":c_compile"],
-    enabled = False,
     feature_name = "simple2",
 )
 
@@ -46,7 +44,6 @@ util.helper_target(
     cc_feature,
     name = "requires",
     args = [":c_compile"],
-    enabled = True,
     feature_name = "requires",
     requires_any_of = [":feature_set"],
 )
@@ -55,7 +52,6 @@ util.helper_target(
     cc_feature,
     name = "implies",
     args = [":c_compile"],
-    enabled = True,
     feature_name = "implies",
     implies = [":simple"],
 )
@@ -68,7 +64,6 @@ util.helper_target(
     cc_feature,
     name = "mutual_exclusion_feature",
     args = [":c_compile"],
-    enabled = True,
     feature_name = "mutual_exclusion",
     mutually_exclusive = [
         ":simple",
@@ -105,14 +100,12 @@ util.helper_target(
     cc_feature,
     name = "overrides",
     args = [":c_compile"],
-    enabled = True,
     overrides = ":builtin_feature",
 )
 
 util.helper_target(
     cc_feature,
     name = "sentinel_feature",
-    enabled = True,
     feature_name = "sentinel_feature_name",
 )
 

tests/rule_based_toolchain/features/features_test.bzl

@@ -41,7 +41,6 @@ def _sentinel_feature_test(env, targets):
     sentinel_feature = env.expect.that_target(targets.sentinel_feature).provider(FeatureInfo)
     sentinel_feature.name().equals("sentinel_feature_name")
     sentinel_feature.args().args().contains_exactly([])
-    sentinel_feature.enabled().equals(True)
 
 def _simple_feature_test(env, targets):
     simple = env.expect.that_target(targets.simple).provider(FeatureInfo)

tests/rule_based_toolchain/toolchain_config/BUILD

@@ -89,7 +89,6 @@ util.helper_target(
     cc_feature,
     name = "compile_feature",
     args = [":compile_args"],
-    enabled = True,
     feature_name = "compile_feature",
 )
 
@@ -107,7 +106,6 @@ util.helper_target(
     cc_feature,
     name = "implies_simple_feature",
     args = [":c_compile_args"],
-    enabled = True,
     feature_name = "implies",
     implies = [":simple_feature"],
 )
@@ -116,7 +114,6 @@ util.helper_target(
     cc_feature,
     name = "overrides_feature",
     args = [":c_compile_args"],
-    enabled = True,
     overrides = ":builtin_feature",
 )
 
@@ -132,7 +129,6 @@ util.helper_target(
     cc_feature,
     name = "requires_all_simple_feature",
     args = [":c_compile_args"],
-    enabled = True,
     feature_name = "requires_any_simple",
     requires_any_of = [":all_simple_features"],
 )
@@ -141,7 +137,6 @@ util.helper_target(
     cc_feature,
     name = "requires_any_simple_feature",
     args = [":c_compile_args"],
-    enabled = True,
     feature_name = "requires_any_simple",
     requires_any_of = [
         ":simple_feature",
@@ -153,7 +148,6 @@ util.helper_target(
     cc_feature,
     name = "same_feature_name",
     args = [":c_compile_args"],
-    enabled = False,
     feature_name = "simple_feature",
     visibility = ["//tests/rule_based_toolchain:__subpackages__"],
 )
@@ -162,7 +156,6 @@ util.helper_target(
     cc_feature,
     name = "simple_feature",
     args = [":c_compile_args"],
-    enabled = False,
     feature_name = "simple_feature",
 )
 
@@ -170,7 +163,6 @@ util.helper_target(
     cc_feature,
     name = "simple_feature2",
     args = [":c_compile_args"],
-    enabled = False,
     feature_name = "simple_feature2",
     visibility = ["//tests/rule_based_toolchain:__subpackages__"],
 )

tests/rule_based_toolchain/toolchain_config/toolchain_config_test.bzl

@@ -197,7 +197,7 @@ def _toolchain_collects_files_test(env, targets):
         ),
         legacy_feature(
             name = "compile_feature",
-            enabled = True,
+            enabled = False,
             flag_sets = [legacy_flag_set(
                 actions = ["c_compile", "cpp_compile"],
                 flag_groups = [