tests: make py_cc_toolchain test of headers/includes work with Bazel 9 (#3276)

Bazel 9 has a small change in cc_library behavior: the includes
attribute populates
the `.includes` instead of `.system_includes`. This is OK for
rules_python, since both
result in the includes being added as system include paths.

To fix, change the test to look at both; as long as the include paths
are in one,
then its OK.

Fixes #3239

Author: rickeylev

tests/cc/current_py_cc_headers/current_py_cc_headers_tests.bzl

@@ -31,9 +31,11 @@ def _test_current_toolchain_headers(name):
             "//command_line_option:extra_toolchains": [CC_TOOLCHAIN],
         },
         attrs = {
-            "header": attr.label(
-                default = "//tests/support/cc_toolchains:fake_header.h",
-                allow_single_file = True,
+            "header_files": attr.label_list(
+                default = [
+                    "//tests/support/cc_toolchains:py_header_files",
+                ],
+                allow_files = True,
             ),
         },
     )
@@ -44,17 +46,23 @@ def _test_current_toolchain_headers_impl(env, target):
         CcInfo,
         factory = cc_info_subject,
     ).compilation_context()
-    compilation_context.direct_headers().contains_exactly([
-        env.ctx.file.header,
-    ])
-    compilation_context.direct_public_headers().contains_exactly([
-        env.ctx.file.header,
-    ])
+    compilation_context.direct_headers().contains_exactly(
+        env.ctx.files.header_files,
+    )
+    compilation_context.direct_public_headers().contains_exactly(
+        env.ctx.files.header_files,
+    )
+
+    # NOTE: Bazel 8 and lower put cc_library.includes into `.system_includes`,
+    # while Bazel 9 put it in `.includes`. Both result in the includes being
+    # added as system includes, so either is acceptable for the expected
+    # `#include <Python.h>` to work.
+    includes = compilation_context.actual.includes.to_list() + compilation_context.actual.system_includes.to_list()
 
     # NOTE: The include dir gets added twice, once for the source path,
     # and once for the config-specific path.
-    compilation_context.system_includes().contains_at_least_predicates([
-        matching.str_matches("*/fake_include"),
+    env.expect.that_collection(includes).contains_at_least_predicates([
+        matching.str_matches("*/py_include"),
     ])
 
     # Check that the forward DefaultInfo looks correct

tests/cc/py_cc_toolchain/py_cc_toolchain_tests.bzl

@@ -28,9 +28,9 @@ def _test_py_cc_toolchain(name):
         impl = _test_py_cc_toolchain_impl,
         target = "//tests/support/cc_toolchains:fake_py_cc_toolchain_impl",
         attrs = {
-            "header": attr.label(
-                default = "//tests/support/cc_toolchains:fake_header.h",
-                allow_single_file = True,
+            "header_files": attr.label_list(
+                default = ["//tests/support/cc_toolchains:py_header_files"],
+                allow_files = True,
             ),
         },
     )
@@ -50,17 +50,17 @@ def _test_py_cc_toolchain_impl(env, target):
     cc_info = headers_providers.get("CcInfo", factory = cc_info_subject)
 
     compilation_context = cc_info.compilation_context()
-    compilation_context.direct_headers().contains_exactly([
-        env.ctx.file.header,
-    ])
-    compilation_context.direct_public_headers().contains_exactly([
-        env.ctx.file.header,
-    ])
+    compilation_context.direct_headers().contains_exactly(
+        env.ctx.files.header_files,
+    )
+    compilation_context.direct_public_headers().contains_exactly(
+        env.ctx.files.header_files,
+    )
 
     # NOTE: The include dir gets added twice, once for the source path,
     # and once for the config-specific path, but we don't care about that.
     compilation_context.system_includes().contains_at_least_predicates([
-        matching.str_matches("*/fake_include"),
+        matching.str_matches("*/py_include"),
     ])
 
     default_info = headers_providers.get("DefaultInfo", factory = subjects.default_info)
@@ -87,7 +87,7 @@ def _test_libs_optional(name):
     py_cc_toolchain(
         name = name + "_subject",
         libs = None,
-        headers = "//tests/support/cc_toolchains:fake_headers",
+        headers = "//tests/support/cc_toolchains:py_headers",
         python_version = "4.5",
     )
     analysis_test(

tests/support/cc_info_subject.bzl

@@ -81,6 +81,7 @@ def _compilation_context_subject_new(info, *, meta):
 
     # buildifier: disable=uninitialized
     public = struct(
+        actual = info,
         # go/keep-sorted start
         direct_headers = lambda *a, **k: _compilation_context_subject_direct_headers(self, *a, **k),
         direct_public_headers = lambda *a, **k: _compilation_context_subject_direct_public_headers(self, *a, **k),
@@ -156,6 +157,7 @@ def _linking_context_subject_new(info, meta):
 
     # buildifier: disable=uninitialized
     public = struct(
+        actual = info,
         # go/keep-sorted start
         linker_inputs = lambda *a, **k: _linking_context_subject_linker_inputs(self, *a, **k),
         # go/keep-sorted end

tests/support/cc_toolchains/BUILD.bazel

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+load("@rules_cc//cc:cc_library.bzl", "cc_library")
 load("@rules_cc//cc/toolchains:cc_toolchain.bzl", "cc_toolchain")
 load("@rules_cc//cc/toolchains:cc_toolchain_suite.bzl", "cc_toolchain_suite")
 load("@rules_testing//lib:util.bzl", "PREVENT_IMPLICIT_BUILDING_TAGS")
@@ -20,7 +21,14 @@ load(":fake_cc_toolchain_config.bzl", "fake_cc_toolchain_config")
 
 package(default_visibility = ["//:__subpackages__"])
 
-exports_files(["fake_header.h"])
+# Factored out for testing
+filegroup(
+    name = "py_header_files",
+    srcs = [
+        "py_header.h",
+        "py_include/py_include.h",
+    ],
+)
 
 filegroup(
     name = "libpython",
@@ -37,22 +45,20 @@ toolchain(
 
 py_cc_toolchain(
     name = "fake_py_cc_toolchain_impl",
-    headers = ":fake_headers",
+    headers = ":py_headers",
     libs = ":fake_libs",
     python_version = "3.999",
     tags = PREVENT_IMPLICIT_BUILDING_TAGS,
 )
 
-# buildifier: disable=native-cc
 cc_library(
-    name = "fake_headers",
-    hdrs = ["fake_header.h"],
+    name = "py_headers",
+    hdrs = [":py_header_files"],
     data = ["data.txt"],
-    includes = ["fake_include"],
+    includes = ["py_include"],
     tags = PREVENT_IMPLICIT_BUILDING_TAGS,
 )
 
-# buildifier: disable=native-cc
 cc_library(
     name = "fake_libs",
     srcs = ["libpython3.so"],