Allow the feature configuration to support structured build variables of nested
list type.
RELNOTES: None.
PiperOrigin-RevId: 100024899
diff --git a/third_party/com/github/bazelbuild/bazel/src/main/protobuf/crosstool_config.proto b/third_party/com/github/bazelbuild/bazel/src/main/protobuf/crosstool_config.proto
index 7b87658..f59caaf 100644
--- a/third_party/com/github/bazelbuild/bazel/src/main/protobuf/crosstool_config.proto
+++ b/third_party/com/github/bazelbuild/bazel/src/main/protobuf/crosstool_config.proto
@@ -64,9 +64,27 @@
// ... will get expanded to -I /to/path1 -I /to/path2 ... for each
// include_path /to/pathN.
//
+ // Flag groups can be nested; if they are, the flag group must only contain
+ // other flag groups (no flags) so the order is unambiguously specified.
+ // Nested flag groups require build variables of nested list types, and
+ // will be expanded recursively.
+ //
+ // For example:
+ // flag_group {
+ // flag_group { flag: '--start-lib' }
+ // flag_group { flag: '%{object_files}' }
+ // flag_group { flag: '--end-lib' }
+ // }
+ // ... will get expanded to
+ // --start-lib a1.o a2.o ... --end-lib --start-lib b1.o b2.o .. --end-lib
+ // with %{object_files} being a variable of nested list type
+ // [['a1.o', 'a2.o', ...], ['b1.o', 'b2.o', ...], ...].
+ //
// TODO(bazel-team): Write more elaborate documentation and add a link to it.
message FlagGroup {
repeated string flag = 1;
+
+ repeated FlagGroup flag_group = 2;
}
// A set of features; used to support logical 'and' when specifying feature
