Fixes in preparation for symbolic macros (#137)

* Recognize symbolic macros as supported kinds
* Fix handling of main repo labels in `select`s
* Fix handling of `None` attribute values
* Ensure that all rewritten labels are prefixed with the macro name
including subdirs
* Enable dynamic_deps test on macOS with Bazel 8 and later
* Apply buildifier

examples/MODULE.bazel

@@ -6,6 +6,7 @@ local_path_override(
     path = "..",
 )
 
+bazel_dep(name = "bazel_features", version = "1.21.0")
 bazel_dep(name = "bazel_skylib", version = "1.7.1")
 bazel_dep(name = "contrib_rules_jvm", version = "0.27.0")
 bazel_dep(name = "platforms", version = "0.0.10")

examples/builder_reuse/builder.bzl

@@ -23,6 +23,7 @@ second_builder = _first_builder.clone()
 
 # Demonstrate that the builder does not capture mutable values by reference.
 _first_builder_copt_default[0] = "-DC_VALUE=\"unexpected\""
+
 # Demonstrate that clone() does not share mutable state with the original builder.
 second_builder.set(
     "cxxopt",

examples/dynamic_deps/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@bazel_features//:features.bzl", "bazel_features")
 load("//dynamic_deps/rules:runfiles_dir.bzl", "runfiles_dir")
 load(":cc_define_binary.bzl", "cc_define_binary")
 
@@ -29,18 +30,16 @@ sh_test(
         "//conditions:default": ["$(rlocationpath :bin_runfiles)/bin"],
     }),
     data = [":bin_runfiles"],
-    deps = ["@bazel_tools//tools/bash/runfiles"],
     target_compatible_with = select({
         # TODO: Get this test to pass on Windows.
         "@platforms//os:windows": ["@platforms//:incompatible"],
-        # TODO: Reenable on macOS after:
-        # 1. Bazel is released with the fix in https://github.com/bazelbuild/bazel/pull/23089.
-        # 2. Enabling --incompatible_macos_set_install_name.
-        # 3. Adding a dep on apple_support, as the default Unix toolchain only supports this flag
-        #    after https://github.com/bazelbuild/bazel/pull/23090.
-        "@platforms//os:macos": ["@platforms//:incompatible"],
+        # Requires https://github.com/bazelbuild/bazel/pull/23089 and the flip
+        # of --incompatible_macos_set_install_name on macOS. Use a feature
+        # introduced in Bazel 8 as a proxy for the fix.
+        "@platforms//os:macos": [] if bazel_features.rules.rule_extension_apis_available else ["@platforms//:incompatible"],
         "//conditions:default": [],
     }),
+    deps = ["@bazel_tools//tools/bash/runfiles"],
 )
 
 sh_test(

examples/dynamic_deps/lib/BUILD.bazel

@@ -2,13 +2,13 @@ cc_library(
     name = "lib",
     srcs = ["lib.cpp"],
     hdrs = ["lib.h"],
-    visibility = ["//dynamic_deps:__pkg__"],
     tags = ["manual"],
+    visibility = ["//dynamic_deps:__pkg__"],
 )
 
 cc_shared_library(
     name = "shared",
-    deps = [":lib"],
-    visibility = ["//dynamic_deps:__pkg__"],
     tags = ["manual"],
+    visibility = ["//dynamic_deps:__pkg__"],
+    deps = [":lib"],
 )

with_cfg/private/select.bzl

@@ -167,8 +167,14 @@ def consume_single_value(r, pos):
         string, after_string = _consume_string(r, pos)
 
         # On Bazel 6, stringification of Labels may not include the leading `@@`.
+        # Labels in the main repository are not prefixed with `@` at all since
+        # their `repr` implementation doesn't use the unambiguous form as of
+        # Bazel 8.
         if not string.startswith("@@"):
-            string = "@" + string
+            if string.startswith("@"):
+                string = "@" + string
+            else:
+                string = "@@" + string
 
         # Skip over `)`.
         return Label(string), after_string + 1

with_cfg/private/with_cfg.bzl

@@ -130,10 +130,12 @@ def with_cfg(
     )
     return make_builder(rule_info)
 
-def get_rule_name(rule_or_macro):
-    s = str(rule_or_macro)
+def get_rule_name(kind):
+    s = str(kind)
     if s.startswith("<rule "):
         return s.removeprefix("<rule ").removesuffix(">")
+    elif s.startswith("<macro "):
+        return s.removeprefix("<macro ").removesuffix(">")
     elif s.startswith("<built-in rule "):
         return s.removeprefix("<built-in rule ").removesuffix(">")
     elif s.startswith("<function "):
@@ -150,8 +152,8 @@ def is_test(rule_name):
     # shouldn't become configurable.
     return rule_name.endswith("_test") or rule_name == "go_test_macro"
 
-def _is_native(rule_or_macro):
-    return str(rule_or_macro).startswith("<built-in rule ")
+def _is_native(kind):
+    return str(kind).startswith("<built-in rule ")
 
 def get_implicit_targets(rule_name):
     return IMPLICIT_TARGETS.get(rule_name, [])

with_cfg/private/wrapper.bzl

@@ -139,7 +139,7 @@ def _wrapper(
             tags = ["manual"],
             visibility = ["//visibility:private"],
         ),
-        basename = basename,
+        name_prefix = name,
     )
     rule_info.kind(
         name = original_name,
@@ -192,7 +192,7 @@ def _wrapper(
             **(alias_attrs | common_attrs)
         )
 
-def _process_attrs_for_reset(*, attrs, attrs_to_reset, reset_target, basename):
+def _process_attrs_for_reset(*, attrs, attrs_to_reset, reset_target, name_prefix):
     if not attrs_to_reset:
         return attrs
 
@@ -209,7 +209,7 @@ def _process_attrs_for_reset(*, attrs, attrs_to_reset, reset_target, basename):
             dep = dep,
             label_map = label_map,
             reset_target = reset_target,
-            base_target_name = basename + "__" + attr,
+            name_prefix = name_prefix + "__" + attr,
             mutable_num_calls = mutable_num_calls,
         )
         first_pass_attrs[attr] = map_attr(attr_func, attrs[attr])
@@ -223,47 +223,49 @@ def _process_attrs_for_reset(*, attrs, attrs_to_reset, reset_target, basename):
 
     return second_pass_attrs
 
-def _replace_dep_attr(*, dep, label_map, reset_target, base_target_name, mutable_num_calls):
+def _replace_dep_attr(*, dep, label_map, reset_target, name_prefix, mutable_num_calls):
+    if dep == None:
+        return dep
     if is_list(dep):
         # attr.label_list
         return [
             _replace_single_dep(
                 label_string = label_string,
                 label_map = label_map,
                 reset_target = reset_target,
-                base_target_name = base_target_name,
+                name_prefix = name_prefix,
                 mutable_num_calls = mutable_num_calls,
             )
             for label_string in dep
         ]
-    elif is_dict(dep):
+    if is_dict(dep):
         # attr.label_keyed_string_dict (only the keys represent deps)
         return {
             _replace_single_dep(
                 label_string = label_string,
                 label_map = label_map,
                 reset_target = reset_target,
-                base_target_name = base_target_name,
+                name_prefix = name_prefix,
                 mutable_num_calls = mutable_num_calls,
             ): v
             for label_string, v in dep.items()
         }
-    else:
-        # attr.label
-        return _replace_single_dep(
-            label_string = dep,
-            label_map = label_map,
-            reset_target = reset_target,
-            base_target_name = base_target_name,
-            mutable_num_calls = mutable_num_calls,
-        )
+
+    # attr.label
+    return _replace_single_dep(
+        label_string = dep,
+        label_map = label_map,
+        reset_target = reset_target,
+        name_prefix = name_prefix,
+        mutable_num_calls = mutable_num_calls,
+    )
 
 def _replace_single_dep(
         *,
         label_string,
         label_map,
         reset_target,
-        base_target_name,
+        name_prefix,
         mutable_num_calls):
     use_label = is_label(label_string)
     if not use_label and not is_string(label_string):
@@ -273,7 +275,7 @@ def _replace_single_dep(
         target_label_string = label_map[label]
     else:
         # Multiple targets can be referenced in a single logical dep if that dep is a select.
-        target_name = base_target_name + "_" + str(mutable_num_calls[0])
+        target_name = name_prefix + "_" + str(mutable_num_calls[0])
         reset_target(
             name = target_name,
             exports = label,