Separate build script data from compile_data

cargo/private/cargo_build_script.bzl

@@ -688,7 +688,8 @@ def _cargo_build_script_impl(ctx):
             flags = flags_out,
             linker_flags = link_flags,
             link_search_paths = link_search_paths,
-            compile_data = depset([runfiles_dir] + extra_output, transitive = script_data),
+            build_script_data = depset(transitive = script_data),
+            compile_data = depset([runfiles_dir] + extra_output),
         ),
         OutputGroupInfo(
             **output_groups

cargo/private/cargo_dep_env.bzl

@@ -35,6 +35,7 @@ def _cargo_dep_env_impl(ctx):
             link_search_paths = empty_file,
             out_dir = out_dir,
             rustc_env = empty_file,
+            build_script_data = depset([]),
             compile_data = depset([]),
         ))
     return [
@@ -54,6 +55,7 @@ def _cargo_dep_env_impl(ctx):
             link_search_paths = empty_file,
             out_dir = None,
             rustc_env = empty_file,
+            build_script_data = depset([]),
             compile_data = depset([]),
         ),
         # Information here is used directly by dependencies, and it is an error to have more than

cargo/tests/cargo_build_script/transitive_data/transitive_data_test.bzl

@@ -1,6 +1,4 @@
-"""Tests documenting that cargo_build_script `data` files currently act as both
-compile_data and runtime data -- they appear in Rustc compile action inputs for
-both the direct library and transitive dependents.
+"""Tests for cargo_build_script `data` propagation into Rustc compile actions.
 
 See https://github.com/bazelbuild/rules_rust/issues/3609 for context."""
 
@@ -21,21 +19,20 @@ def _cbs_data_in_rustc_inputs_impl(ctx):
 
     asserts.false(env, rustc_action == None, "Expected a Rustc action")
 
-    # cargo_build_script `data` currently flows into BuildInfo.compile_data
-    # via script_data, so it appears in Rustc action inputs for both the
-    # direct dependent and transitive dependents. This documents that
-    # CBS `data` effectively acts as both compile_data and data today.
     data_inputs = [i for i in rustc_action.inputs.to_list() if "cbs_data_dep.txt" in i.path]
-    asserts.true(
+    asserts.equals(
         env,
+        ctx.attr.expected_present,
         len(data_inputs) > 0,
-        "Expected CBS data file to appear in Rustc action inputs (CBS data currently acts as compile_data)",
     )
 
     return analysistest.end(env)
 
 cbs_data_in_rustc_inputs_test = analysistest.make(
     _cbs_data_in_rustc_inputs_impl,
+    attrs = {
+        "expected_present": attr.bool(),
+    },
 )
 
 def _define_test_targets():
@@ -98,11 +95,13 @@ def transitive_cbs_data_test_suite(name):
 
     cbs_data_in_rustc_inputs_test(
         name = "cbs_data_in_lib_compile_inputs_test",
+        expected_present = True,
         target_under_test = ":lib",
     )
 
     cbs_data_in_rustc_inputs_test(
         name = "cbs_data_in_bin_compile_inputs_test",
+        expected_present = False,
         target_under_test = ":bin",
     )
 

extensions/bindgen/private/bindgen.bzl

@@ -178,6 +178,7 @@ def _generate_cc_link_build_info(ctx, cc_lib):
     )
 
     return BuildInfo(
+        build_script_data = depset([]),
         compile_data = depset(compile_data),
         dep_env = None,
         flags = rustc_flags_file,

rust/private/providers.bzl

@@ -79,7 +79,8 @@ CrateGroupInfo = provider(
 BuildInfo = provider(
     doc = "A provider containing `rustc` build settings for a given Crate.",
     fields = {
-        "compile_data": "Depset[File]: Compile data provided by the build script that was not copied into `out_dir`.",
+        "build_script_data": "Depset[File]: Data inputs used by the build script that may also be referenced by its direct dependent.",
+        "compile_data": "Depset[File]: Compile data that should remain available to transitive dependents.",
         "dep_env": "Optional[File]: extra build script environment variables to be set to direct dependencies.",
         "flags": "Optional[File]: file containing additional flags to pass to rustc",
         "link_search_paths": "Optional[File]: file containing search paths to pass to rustc and linker",

rust/private/rustc.bzl

@@ -2196,6 +2196,7 @@ def _process_build_scripts(
             direct_inputs.append(build_info.linker_flags)
 
         transitive_inputs.append(build_info.compile_data)
+        transitive_inputs.append(getattr(build_info, "build_script_data", depset()))
 
     # We include transitive dep build_infos because cargo build scripts may generate files which get linked into the final binary.
     # This should probably only actually be exposed to actions which link.