Include transitive out directories when running rustc

.bazelci/presubmit.yml

@@ -68,6 +68,12 @@ default_macos_targets: &default_macos_targets
   - "//..."
   # Not sure why this doesn't work on bazelci, it does locally on macOS.
   - "-//test/unit/remap_path_prefix:integration_test"
+default_macos_coverage_targets: &default_macos_coverage_targets
+  - "--"
+  - "//..."
+  # Not sure why these don't work on bazelci, it does locally on macOS.
+  - "-//test/unit/remap_path_prefix:integration_test"
+  - "-//test/linking_out_dir:test"
 default_windows_targets: &default_windows_targets
   - "--" # Allows negative patterns; hack for https://github.com/bazelbuild/continuous-integration/pull/245
   - "//..."
@@ -110,7 +116,7 @@ tasks:
     platform: macos_arm64
     build_targets: *default_macos_targets
     test_targets: *default_macos_targets
-    coverage_targets: *default_macos_targets
+    coverage_targets: *default_macos_coverage_targets
     post_shell_commands: *coverage_validation_post_shell_commands
   windows:
     build_targets: *default_windows_targets
@@ -140,7 +146,7 @@ tasks:
     shell_commands: *no_bzlmod_shell_commands
     build_targets: *default_macos_targets
     test_targets: *default_macos_targets
-    coverage_targets: *default_macos_targets
+    coverage_targets: *default_macos_coverage_targets
     post_shell_commands: *coverage_validation_post_shell_commands
   windows_no_bzlmod:
     name: No Bzlmod
@@ -167,7 +173,7 @@ tasks:
     name: Split Coverage Postprocessing
     platform: macos_arm64
     shell_commands: *split_coverage_postprocessing_shell_commands
-    coverage_targets: *default_macos_targets
+    coverage_targets: *default_macos_coverage_targets
     post_shell_commands: *coverage_validation_post_shell_commands
   ubuntu2204_opt:
     name: Opt Mode
@@ -230,15 +236,15 @@ tasks:
     build_flags: *aspects_flags
     build_targets: *default_macos_targets
     test_targets: *default_macos_targets
-    coverage_targets: *default_macos_targets
+    coverage_targets: *default_macos_coverage_targets
     post_shell_commands: *coverage_validation_post_shell_commands
   macos_rolling_with_aspects:
     name: "Macos Rolling Bazel Version With Aspects"
     platform: macos_arm64
     build_flags: *aspects_flags
     build_targets: *default_macos_targets
     test_targets: *default_macos_targets
-    coverage_targets: *default_macos_targets
+    coverage_targets: *default_macos_coverage_targets
     post_shell_commands: *coverage_validation_post_shell_commands
     soft_fail: yes
     bazel: "rolling"

rust/private/providers.bzl

@@ -59,6 +59,7 @@ DepInfo = provider(
         "transitive_data": "depset[File]: Data of all transitive non-macro dependencies.",
         "transitive_metadata_outputs": "depset[File]: All transitive metadata dependencies (.rmeta, for crates that provide them) and all transitive object dependencies (.rlib) for crates that don't provide metadata.",
         "transitive_noncrates": "depset[LinkerInput]: All transitive dependencies that aren't crates.",
+        "transitive_out_dirs": "depset[File]: The out directories of the build scripts of all transitive dependencies",
         "transitive_proc_macro_data": "depset[File]: Data of all transitive proc-macro dependencies, and non-macro dependencies of those macros.",
     },
 )

rust/private/rustc.bzl

@@ -226,6 +226,7 @@ def collect_deps(
     transitive_proc_macro_data = []
     transitive_noncrates = []
     transitive_build_infos = []
+    transitive_out_dirs = []
     transitive_link_search_paths = []
     build_info = None
     linkstamps = []
@@ -321,6 +322,7 @@ def collect_deps(
                 transitive_link_search_paths.append(dep_info.link_search_path_files)
 
             transitive_build_infos.append(dep_info.transitive_build_infos)
+            transitive_out_dirs.append(dep_info.transitive_out_dirs)
         elif cc_info or dep_build_info:
             if cc_info:
                 # This dependency is a cc_library
@@ -332,6 +334,8 @@ def collect_deps(
                          "only one is allowed in the dependencies")
                 build_info = dep_build_info
                 transitive_build_infos.append(depset([build_info]))
+                if build_info.out_dir:
+                    transitive_out_dirs.append(depset([build_info.out_dir]))
                 if build_info.link_search_paths:
                     transitive_link_search_paths.append(depset([build_info.link_search_paths]))
                 transitive_data.append(build_info.compile_data)
@@ -356,6 +360,7 @@ def collect_deps(
             transitive_crate_outputs = depset(transitive = transitive_crate_outputs),
             transitive_metadata_outputs = depset(transitive = transitive_metadata_outputs),
             transitive_build_infos = depset(transitive = transitive_build_infos),
+            transitive_out_dirs = depset(transitive = transitive_out_dirs),
             link_search_path_files = depset(transitive = transitive_link_search_paths),
             dep_env = build_info.dep_env if build_info else None,
         ),
@@ -1872,7 +1877,7 @@ def _create_extra_input_args(build_info, dep_info, include_link_flags = True):
 
     out_dir_compile_inputs = depset(
         input_files,
-        transitive = [dep_info.link_search_path_files, dep_info.transitive_data] + input_depsets,
+        transitive = [dep_info.link_search_path_files, dep_info.transitive_data, dep_info.transitive_out_dirs] + input_depsets,
     )
 
     return (

test/linking_out_dir/BUILD.bazel

@@ -0,0 +1,47 @@
+"""Tests that cargo build scripts can create archives in OUT_DIR and link to
+them. This requires that binaries or shared libraries include the out dirs of
+transitive dependencies when linking."""
+
+load("@bazel_skylib//rules:native_binary.bzl", "native_test")
+load("@rules_cc//cc:cc_library.bzl", "cc_library")
+load("//cargo:defs.bzl", "cargo_build_script")
+load("//rust:defs.bzl", "rust_binary", "rust_library")
+
+cc_library(
+    name = "foo",
+    srcs = ["foo.c"],
+)
+
+filegroup(
+    name = "foo_static",
+    srcs = [":foo"],
+    output_group = "archive",
+)
+
+cargo_build_script(
+    name = "build_script",
+    srcs = ["build.rs"],
+    build_script_env = {"ARCHIVE_PATH": "$(execpath :foo_static)"},
+    crate_root = "build.rs",
+    data = [":foo_static"],
+    edition = "2021",
+)
+
+rust_library(
+    name = "bar",
+    srcs = ["bar.rs"],
+    edition = "2021",
+    deps = [":build_script"],
+)
+
+rust_binary(
+    name = "main",
+    srcs = ["main.rs"],
+    edition = "2021",
+    deps = [":bar"],
+)
+
+native_test(
+    name = "test",
+    src = ":main",
+)

test/linking_out_dir/bar.rs

@@ -0,0 +1,7 @@
+extern "C" {
+    fn foo() -> i32;
+}
+
+pub fn bar() -> i32 {
+    unsafe { foo() }
+}

test/linking_out_dir/build.rs

@@ -0,0 +1,17 @@
+use std::env;
+use std::path::PathBuf;
+
+const ARCHIVE_NAME: &'static str = "test_linking_out_dir_foo";
+
+fn main() {
+    let out_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
+
+    let src = env::var_os("ARCHIVE_PATH").unwrap();
+
+    let dst = out_dir.join(format!("lib{ARCHIVE_NAME}.a"));
+
+    std::fs::copy(&src, &dst).unwrap();
+
+    println!("cargo:rustc-link-lib={ARCHIVE_NAME}");
+    println!("cargo:rustc-link-search=native={}", out_dir.display());
+}

test/linking_out_dir/foo.c

@@ -0,0 +1,3 @@
+#include <stdint.h>
+
+int32_t foo() { return 1; }

test/linking_out_dir/main.rs

@@ -0,0 +1,5 @@
+pub fn main() {
+    let result = bar::bar();
+
+    assert_eq!(result, 1);
+}