build/rust/build.gni

# Copyright 2024 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

declare_args() {
  # Place lengthy rustdeps and externs (GN) into ninja response files.
  # Response files are needed to get around command line length limitations.
  # rustc support for response files (as needed in our GN build) was
  # added with revision 'git_revision:dfe53afaebd817f334d8ef9dc75a5cd2562cf6e6'.
  rustc_use_response_files = true

  # To avoid build nondeterminism due to extern search paths resolving
  # to more than one path during a build, this option places every rlib
  # into its own exclusive directory. This requires
  # `rustc_use_response_file = true` due to the command-line bloat this causes.
  rust_one_rlib_per_dir = true

  # Controls whether the build runs the depfile verifier
  verify_depfile = true
}

assert(
    !rust_one_rlib_per_dir || rustc_use_response_files,
    "rust_one_rlib_per_dir requires rustc_use_response_files, due to command-line length limits.")