rs_bindings_from_cc: Fix hardcoded ::co in generator

rs_bindings_from_cc/generate_bindings/database/rs_snippet.rs

@@ -2354,6 +2354,11 @@ impl<'a> RsTypeKind<'a> {
                         quote! { ::alloc::boxed::Box<#callable_spelling> }
                     }
                     BridgeRsTypeKind::C9Co { has_reference_param, result_type, lifetime, .. } => {
+                        let co_crate = db
+                            .ir()
+                            .crate_name(&BazelLabel::from("//util/c9:co"))
+                            .map(|ident| quote! { ::#ident })
+                            .unwrap_or_else(|| quote! { ::co });
                         let result_type_tokens = if result_type.is_void() {
                             quote! { () }
                         } else {
@@ -2362,9 +2367,9 @@ impl<'a> RsTypeKind<'a> {
                         // When there are reference parameters, the coroutine must finish before they are
                         // invalidated (http://shortn/_XPma06AwZh).
                         match (lifetime, has_reference_param) {
-                            (Some(lt), _) => quote! { ::co::Co<#lt, #result_type_tokens> },
-                            (_, false) => quote! { ::co::Co<'static, #result_type_tokens> },
-                            (_, true) => quote! { ::co::Co<'_, #result_type_tokens> },
+                            (Some(lt), _) => quote! { #co_crate::Co<#lt, #result_type_tokens> },
+                            (_, false) => quote! { #co_crate::Co<'static, #result_type_tokens> },
+                            (_, true) => quote! { #co_crate::Co<'_, #result_type_tokens> },
                         }
                     }
                 }

rs_bindings_from_cc/generate_bindings/lib.rs

@@ -1198,13 +1198,19 @@ fn crubit_abi_type<'a>(
                 generate_dyn_callable::callable_crubit_abi_type(db, &callable)
             }
             BridgeRsTypeKind::C9Co { result_type, .. } => {
+                let co_crate = db
+                    .ir()
+                    .crate_name(&BazelLabel::from("//util/c9:co"))
+                    .map(|ident| quote! { ::#ident })
+                    .unwrap_or_else(|| quote! { ::co });
+
                 let result_type_tokens = if result_type.is_void() {
                     quote! { () }
                 } else {
                     result_type.all_static_lifetimes(false).to_token_stream(db)
                 };
                 let rust_type_tokens = quote! {
-                    ::co::internal_crubit::CoCrubitAbi<#result_type_tokens>
+                    #co_crate::internal_crubit::CoCrubitAbi<#result_type_tokens>
                 };
 
                 let result_type_crubit_abi_type = if result_type.is_void() {
@@ -1215,7 +1221,7 @@ fn crubit_abi_type<'a>(
 
                 let rust_expr_tokens = {
                     let consume_result_fn = match &result_type_crubit_abi_type {
-                        None => quote! { ::co::internal_crubit::consume_void_result },
+                        None => quote! { #co_crate::internal_crubit::consume_void_result },
                         Some(result_type_crubit_abi_type) => {
                             let result_type_crubit_abi_type_tokens =
                                 CrubitAbiTypeToRustTokens(result_type_crubit_abi_type);
@@ -1229,7 +1235,7 @@ fn crubit_abi_type<'a>(
                             // and a pointer to the buffer, and then decode the stack buffer into
                             // the native Rust value.
                             quote! {
-                                |consume_result_into_buffer: ::co::internal_crubit::ConsumeResultIntoBufferFn,
+                                |consume_result_into_buffer: #co_crate::internal_crubit::ConsumeResultIntoBufferFn,
                                  context: *mut ::core::ffi::c_void| -> #result_type_tokens {
                                     ::bridge_rust::unstable_return!(@
                                         // Crubit ABI details
@@ -1251,7 +1257,7 @@ fn crubit_abi_type<'a>(
                         }
                     };
                     quote! {
-                        ::co::internal_crubit::CoCrubitAbi::new(#consume_result_fn)
+                        #co_crate::internal_crubit::CoCrubitAbi::new(#consume_result_fn)
                     }
                 };
 

rs_bindings_from_cc/test/bazel/co_reproducer/BUILD

@@ -0,0 +1,90 @@
+# Part of the Crubit project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+# Regression test for c9::Co crate name hardcoding.
+#
+# Historically, the Crubit generator hardcoded the name of the `c9::Co`
+# bindings crate as `::co`. This caused issues when:
+# 1. Crate renaming was enabled (which mangles the crate name to its label-encoded version).
+# 2. A user-defined Rust library also named `co` was present in the dependency
+#    graph (e.g. via `additional_rust_srcs`), causing `::co` to resolve to the
+#    wrong crate.
+#
+# This test verifies that we can compile bindings that use `c9::Co` even when
+# a conflicting user-defined `co` crate is present in the dependencies,
+# provided that crate renaming is enabled.
+
+load("@bazel_tools//tools/build_defs/build_test:build_test.bzl", "build_test")
+load("@rules_cc//cc:cc_library.bzl", "cc_library")
+load("@rules_rust//rust:defs.bzl", "rust_library")
+load(
+    "//rs_bindings_from_cc/bazel_support:additional_rust_srcs_for_crubit_bindings_aspect_hint.bzl",
+    "additional_rust_srcs_for_crubit_bindings",
+)
+
+package(
+    default_testonly = 1,
+)
+
+config_setting(
+    name = "use_label_encoded_names_for_deps_enabled",
+    flag_values = {
+        "//common/bazel_support:use_label_encoded_names_for_deps": "True",
+    },
+)
+
+_compatible_with_flag = select({
+    ":use_label_encoded_names_for_deps_enabled": [],
+    "//conditions:default": ["//third_party/bazel_platforms:incompatible"],
+})
+
+_tags = [
+    "notap",
+    "noguitar",
+    "manual",
+    "nobuilder",
+]
+
+rust_library(
+    name = "co",
+    srcs = ["rust_co.rs"],
+    tags = _tags,
+)
+
+additional_rust_srcs_for_crubit_bindings(
+    name = "extra_srcs",
+    srcs = ["extra.rs"],
+    deps = [":co"],
+)
+
+cc_library(
+    name = "co_usage_cc",
+    hdrs = ["co_usage.h"],
+    aspect_hints = [
+        ":extra_srcs",
+        "//features:supported",
+    ],
+    tags = _tags,
+    target_compatible_with = _compatible_with_flag,
+    deps = [
+        "//util/c9:co",
+    ],
+)
+
+rust_library(
+    name = "co_usage_rust",
+    srcs = ["co_usage.rs"],
+    cc_deps = [":co_usage_cc"],
+    tags = _tags,
+    target_compatible_with = _compatible_with_flag,
+)
+
+build_test(
+    name = "build_test",
+    tags = _tags,
+    target_compatible_with = _compatible_with_flag,
+    targets = [
+        ":co_usage_rust",
+    ],
+)

rs_bindings_from_cc/test/bazel/co_reproducer/co_usage.h

@@ -0,0 +1,12 @@
+// Part of the Crubit project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#ifndef THIRD_PARTY_CRUBIT_RS_BINDINGS_FROM_CC_TEST_BAZEL_CO_REPRODUCER_CO_USAGE_H_
+#define THIRD_PARTY_CRUBIT_RS_BINDINGS_FROM_CC_TEST_BAZEL_CO_REPRODUCER_CO_USAGE_H_
+
+#include "util/c9/co.h"
+
+c9::Co<int> func_returning_co();
+
+#endif  // THIRD_PARTY_CRUBIT_RS_BINDINGS_FROM_CC_TEST_BAZEL_CO_REPRODUCER_CO_USAGE_H_

rs_bindings_from_cc/test/bazel/co_reproducer/co_usage.rs

@@ -0,0 +1,5 @@
+// Part of the Crubit project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// Placeholder file to satisfy rust_library

rs_bindings_from_cc/test/bazel/co_reproducer/extra.rs

@@ -0,0 +1,9 @@
+// Part of the Crubit project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// This imports the placeholder co crate, causing a collision if the generator
+// uses the hardcoded `::co` name.
+extern crate co;
+
+pub use co::Placeholder;

rs_bindings_from_cc/test/bazel/co_reproducer/rust_co.rs

@@ -0,0 +1,6 @@
+// Part of the Crubit project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// Placeholder co library to cause collision
+pub struct Placeholder;