Provide a default toolchain_identifier.

BEGIN_PUBLIC
Provide a default toolchain_identifier.

END_PUBLIC

PiperOrigin-RevId: 626172528
Change-Id: I2d23d79b82f4268b462dac79edc4f69a7f865e00

cc/toolchains/impl/toolchain_config.bzl

@@ -71,7 +71,10 @@ def _cc_toolchain_config_impl(ctx):
  action_configs = legacy.action_configs,
  features = legacy.features,
  cxx_builtin_include_directories = ctx.attr.cxx_builtin_include_directories,
- toolchain_identifier = ctx.attr.toolchain_identifier,
+ # toolchain_identifier is deprecated, but setting it to None results
+ # in an error that it expected a string, and for safety's sake, I'd
+ # prefer to provide something unique.
+ toolchain_identifier = str(ctx.label),
  target_system_name = ctx.attr.target_system_name,
  target_cpu = ctx.attr.target_cpu,
  target_libc = ctx.attr.target_libc,
@@ -105,7 +108,6 @@ cc_toolchain_config = rule(
  # TODO: Consider making this into a label_list that takes a
  # cc_directory_marker rule as input.
  "cxx_builtin_include_directories": attr.string_list(),
- "toolchain_identifier": attr.string(mandatory = True),
  "target_system_name": attr.string(mandatory = True),
  "target_cpu": attr.string(mandatory = True),
  "target_libc": attr.string(mandatory = True),

tests/rule_based_toolchain/toolchain_config/BUILD

@@ -52,7 +52,6 @@ util.helper_target(
  target_libc = "glibc-2.2.2",
  target_system_name = "local",
  toolchain_features = [":compile_feature"],
- toolchain_identifier = "collects_files_toolchain",
 )
 
 util.helper_target(