Use custom absolute path checking function

Author: stevenlr

cc/common/cc_helper.bzl

@@ -13,8 +13,8 @@
 # limitations under the License.
 """Utility functions for C++ rules."""
 
-load("@bazel_skylib//lib:paths.bzl", "paths")
 load("//cc:find_cc_toolchain.bzl", "CC_TOOLCHAIN_TYPE")
+load("//cc/private:paths.bzl", "is_path_absolute")
 load("//cc/private/rules_impl:objc_common.bzl", "objc_common")
 load(":cc_common.bzl", "cc_common")
 load(
@@ -790,7 +790,7 @@ def _include_dirs(ctx, additional_make_variable_substitutions):
     package_source_root = _package_source_root(ctx.label.workspace_name, package, sibling_repository_layout)
     for include in ctx.attr.includes:
         includes_attr = _expand(ctx, include, additional_make_variable_substitutions)
-        if paths.is_absolute(includes_attr):
+        if is_path_absolute(includes_attr):
             continue
         includes_path = get_relative_path(package_exec_path, includes_attr)
         if not sibling_repository_layout and path_contains_up_level_references(includes_path):

cc/common/cc_helper_internal.bzl

@@ -19,6 +19,7 @@ Only use those within C++ implementation. The others need to go through cc_commo
 """
 
 load("@bazel_skylib//lib:paths.bzl", "paths")
+load("//cc/private:paths.bzl", "is_path_absolute")
 
 # LINT.IfChange(forked_exports)
 
@@ -196,7 +197,7 @@ def repository_exec_path(repository, sibling_repository_layout):
 # LINT.ThenChange(https://github.com/bazelbuild/bazel/blob/master/src/main/starlark/builtins_bzl/common/cc/cc_helper_internal.bzl:forked_exports)
 
 def get_relative_path(path_a, path_b):
-    if paths.is_absolute(path_b):
+    if is_path_absolute(path_b):
         return path_b
     return paths.normalize(paths.join(path_a, path_b))
 

cc/private/BUILD

@@ -16,6 +16,7 @@ filegroup(
     name = "srcs",
     srcs = glob([
         "**/BUILD",
+        "*.bzl",
     ]) + [
         "//cc/private/rules_impl:srcs",
         "//cc/private/toolchain:srcs",

cc/private/paths.bzl

@@ -0,0 +1,23 @@
+# Copyright 2025 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+def is_path_absolute(path):
+    if path.startswith("/"):
+        return True
+
+    # Check for DOS-style absolute paths for Windows
+    return len(path) >= 3 and \
+           path[0].isalpha() and \
+           path[1] == ":" and \
+           path[2] in ("/", "\\")

cc/toolchains/args.bzl

@@ -13,8 +13,8 @@
 # limitations under the License.
 """All providers for rule-based bazel toolchain config."""
 
-load("@bazel_skylib//lib:paths.bzl", "paths")
 load("@bazel_skylib//rules/directory:providers.bzl", "DirectoryInfo")
+load("//cc/private:paths.bzl", "is_path_absolute")
 load("//cc/toolchains/impl:args_utils.bzl", "validate_nested_args")
 load(
     "//cc/toolchains/impl:collect.bzl",
@@ -49,7 +49,7 @@ def _cc_args_impl(ctx):
     )
 
     for path in ctx.attr.allowlist_absolute_include_directories:
-        if not paths.is_absolute(path):
+        if not is_path_absolute(path):
             fail("`{}` is not an absolute paths".format(path))
 
     nested = None