Fix exec config check with bazel 9.x

bazelbuild/bazel#29421

Author: keith

MODULE.bazel

@@ -4,6 +4,7 @@ module(
     bazel_compatibility = [">=8.0.0"],
 )
 
+bazel_dep(name = "bazel_features", version = "1.46.0")
 bazel_dep(name = "bazel_skylib", version = "1.7.1")
 bazel_dep(name = "platforms", version = "0.0.11")
 bazel_dep(name = "rules_cc", version = "0.2.16")

mojo/mojo_library.bzl

@@ -2,7 +2,7 @@
 
 load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 load("//mojo:providers.bzl", "MojoInfo")
-load("//mojo/private:utils.bzl", "MOJO_EXTENSIONS", "collect_mojoinfo")
+load("//mojo/private:utils.bzl", "MOJO_EXTENSIONS", "collect_mojoinfo", "is_exec_config")
 
 def _format_include(arg):
     return ["-I", arg.dirname]
@@ -18,7 +18,7 @@ def _mojo_library_implementation(ctx):
     args.add("-o", mojo_package)
 
     args.add_all(mojo_toolchain.package_copts)
-    if "-exec-" not in ctx.bin_dir.path:
+    if not is_exec_config(ctx):
         args.add_all(ctx.attr._mojo_package_copts[BuildSettingInfo].value)
     args.add_all([
         ctx.expand_location(copt, targets = ctx.attr.additional_compiler_inputs)

mojo/private/mojo_binary_test.bzl

@@ -9,7 +9,7 @@ load("@rules_cc//cc/common:cc_info.bzl", "CcInfo")
 load("@rules_python//python:py_info.bzl", "PyInfo")
 load("//mojo:providers.bzl", "MojoInfo")
 load(":transitions.bzl", "python_version_transition")
-load(":utils.bzl", "MOJO_EXTENSIONS", "collect_mojoinfo")
+load(":utils.bzl", "MOJO_EXTENSIONS", "collect_mojoinfo", "is_exec_config")
 
 _PYTHON_TOOLCHAIN_TYPE = "@rules_python//python:toolchain_type"
 _ATTRS = {
@@ -125,7 +125,7 @@ def _mojo_binary_test_implementation(ctx, *, shared_library = False):
     args.add_all(mojo_toolchain.copts)
 
     # Ignore default mojo flags for exec built binaries
-    if "-exec-" not in ctx.bin_dir.path:
+    if not is_exec_config(ctx):
         args.add_all(ctx.attr._mojo_copts[BuildSettingInfo].value)
     args.add_all([
         ctx.expand_location(copt, targets = ctx.attr.additional_compiler_inputs)

mojo/private/utils.bzl

@@ -1,5 +1,6 @@
 """Helpers internal to rules_mojo."""
 
+load("@bazel_features//:features.bzl", "bazel_features")
 load("//mojo:providers.bzl", "MojoInfo")
 
 MOJO_EXTENSIONS = ("mojo", "🔥")
@@ -22,3 +23,23 @@ def collect_mojoinfo(deps):
             import_paths.append(info.import_paths)
 
     return depset(transitive = import_paths), depset(transitive = mojopkgs)
+
+def is_exec_config(ctx):
+    """Determines whether the current configuration is an exec configuration.
+
+    Args:
+        ctx: The rule context.
+
+    Returns:
+        Whether the current configuration is an exec configuration.
+    """
+
+    # TODO: Remove once we drop 9.x
+    if bazel_features.rules.is_tool_configuration_public and ctx.configuration.is_tool_configuration():
+        return True
+    elif ctx.bin_dir.path.endswith("-exec/bin"):  # NOTE: 9.0.0 or <8.7.0 with --experimental_platform_in_output_dir
+        return True
+    elif "-exec-" in ctx.bin_dir.path:
+        return True
+
+    return False