upstream wrappers for cargo, rustc, cargo-clippy (#2703)

...and a bazel_env example.

As discussed in
https://bazelbuild.slack.com/archives/CSV56UT0F/p1718207171652029?thread_ts=1718182474.631279&cid=CSV56UT0F

.bazelignore

@@ -5,3 +5,4 @@ crate_universe/private/bootstrap
 test/bzlmod_repo_mapping
 test/cc_common_link
 test/no_std
+.direnv

docs/flatten.md

@@ -1132,7 +1132,7 @@ Run the test with `bazel test //hello_lib:greeting_test`.
 ## rust_toolchain
 
 <pre>
-rust_toolchain(<a href="#rust_toolchain-name">name</a>, <a href="#rust_toolchain-allocator_library">allocator_library</a>, <a href="#rust_toolchain-binary_ext">binary_ext</a>, <a href="#rust_toolchain-cargo">cargo</a>, <a href="#rust_toolchain-clippy_driver">clippy_driver</a>, <a href="#rust_toolchain-debug_info">debug_info</a>,
+rust_toolchain(<a href="#rust_toolchain-name">name</a>, <a href="#rust_toolchain-allocator_library">allocator_library</a>, <a href="#rust_toolchain-binary_ext">binary_ext</a>, <a href="#rust_toolchain-cargo">cargo</a>, <a href="#rust_toolchain-cargo_clippy">cargo_clippy</a>, <a href="#rust_toolchain-clippy_driver">clippy_driver</a>, <a href="#rust_toolchain-debug_info">debug_info</a>,
                <a href="#rust_toolchain-default_edition">default_edition</a>, <a href="#rust_toolchain-dylib_ext">dylib_ext</a>, <a href="#rust_toolchain-env">env</a>, <a href="#rust_toolchain-exec_triple">exec_triple</a>, <a href="#rust_toolchain-experimental_link_std_dylib">experimental_link_std_dylib</a>,
                <a href="#rust_toolchain-experimental_use_cc_common_link">experimental_use_cc_common_link</a>, <a href="#rust_toolchain-extra_exec_rustc_flags">extra_exec_rustc_flags</a>, <a href="#rust_toolchain-extra_rustc_flags">extra_rustc_flags</a>,
                <a href="#rust_toolchain-extra_rustc_flags_for_crate_types">extra_rustc_flags_for_crate_types</a>, <a href="#rust_toolchain-global_allocator_library">global_allocator_library</a>, <a href="#rust_toolchain-llvm_cov">llvm_cov</a>, <a href="#rust_toolchain-llvm_profdata">llvm_profdata</a>,
@@ -1192,6 +1192,7 @@ See `@rules_rust//rust:repositories.bzl` for examples of defining the `@rust_cpu
 | <a id="rust_toolchain-allocator_library"></a>allocator_library |  Target that provides allocator functions when rust_library targets are embedded in a cc_binary.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional |  `"@rules_rust//ffi/cc/allocator_library"`  |
 | <a id="rust_toolchain-binary_ext"></a>binary_ext |  The extension for binaries created from rustc.   | String | required |  |
 | <a id="rust_toolchain-cargo"></a>cargo |  The location of the `cargo` binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional |  `None`  |
+| <a id="rust_toolchain-cargo_clippy"></a>cargo_clippy |  The location of the `cargo_clippy` binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional |  `None`  |
 | <a id="rust_toolchain-clippy_driver"></a>clippy_driver |  The location of the `clippy-driver` binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional |  `None`  |
 | <a id="rust_toolchain-debug_info"></a>debug_info |  Rustc debug info levels per opt level   | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | optional |  `{"dbg": "2", "fastbuild": "0", "opt": "0"}`  |
 | <a id="rust_toolchain-default_edition"></a>default_edition |  The edition to use for rust_* rules that don't specify an edition. If absent, every rule is required to specify its `edition` attribute.   | String | optional |  `""`  |

docs/rust_repositories.md

@@ -36,7 +36,7 @@ A dedicated filegroup-like rule for Rust stdlib artifacts.
 ## rust_toolchain
 
 <pre>
-rust_toolchain(<a href="#rust_toolchain-name">name</a>, <a href="#rust_toolchain-allocator_library">allocator_library</a>, <a href="#rust_toolchain-binary_ext">binary_ext</a>, <a href="#rust_toolchain-cargo">cargo</a>, <a href="#rust_toolchain-clippy_driver">clippy_driver</a>, <a href="#rust_toolchain-debug_info">debug_info</a>,
+rust_toolchain(<a href="#rust_toolchain-name">name</a>, <a href="#rust_toolchain-allocator_library">allocator_library</a>, <a href="#rust_toolchain-binary_ext">binary_ext</a>, <a href="#rust_toolchain-cargo">cargo</a>, <a href="#rust_toolchain-cargo_clippy">cargo_clippy</a>, <a href="#rust_toolchain-clippy_driver">clippy_driver</a>, <a href="#rust_toolchain-debug_info">debug_info</a>,
                <a href="#rust_toolchain-default_edition">default_edition</a>, <a href="#rust_toolchain-dylib_ext">dylib_ext</a>, <a href="#rust_toolchain-env">env</a>, <a href="#rust_toolchain-exec_triple">exec_triple</a>, <a href="#rust_toolchain-experimental_link_std_dylib">experimental_link_std_dylib</a>,
                <a href="#rust_toolchain-experimental_use_cc_common_link">experimental_use_cc_common_link</a>, <a href="#rust_toolchain-extra_exec_rustc_flags">extra_exec_rustc_flags</a>, <a href="#rust_toolchain-extra_rustc_flags">extra_rustc_flags</a>,
                <a href="#rust_toolchain-extra_rustc_flags_for_crate_types">extra_rustc_flags_for_crate_types</a>, <a href="#rust_toolchain-global_allocator_library">global_allocator_library</a>, <a href="#rust_toolchain-llvm_cov">llvm_cov</a>, <a href="#rust_toolchain-llvm_profdata">llvm_profdata</a>,
@@ -96,6 +96,7 @@ See `@rules_rust//rust:repositories.bzl` for examples of defining the `@rust_cpu
 | <a id="rust_toolchain-allocator_library"></a>allocator_library |  Target that provides allocator functions when rust_library targets are embedded in a cc_binary.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional |  `"@rules_rust//ffi/cc/allocator_library"`  |
 | <a id="rust_toolchain-binary_ext"></a>binary_ext |  The extension for binaries created from rustc.   | String | required |  |
 | <a id="rust_toolchain-cargo"></a>cargo |  The location of the `cargo` binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional |  `None`  |
+| <a id="rust_toolchain-cargo_clippy"></a>cargo_clippy |  The location of the `cargo_clippy` binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional |  `None`  |
 | <a id="rust_toolchain-clippy_driver"></a>clippy_driver |  The location of the `clippy-driver` binary. Can be a direct source or a filegroup containing one item.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional |  `None`  |
 | <a id="rust_toolchain-debug_info"></a>debug_info |  Rustc debug info levels per opt level   | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | optional |  `{"dbg": "2", "fastbuild": "0", "opt": "0"}`  |
 | <a id="rust_toolchain-default_edition"></a>default_edition |  The edition to use for rust_* rules that don't specify an edition. If absent, every rule is required to specify its `edition` attribute.   | String | optional |  `""`  |

examples/.bazelignore

@@ -1,4 +1,5 @@
 android
+bazel_env
 bzlmod
 cargo_manifest_dir/external_crate
 crate_universe

examples/bazel_env/.bazelignore

@@ -0,0 +1 @@
+.direnv

examples/bazel_env/.bazelrc

@@ -0,0 +1,15 @@
+# Required on windows
+common --enable_platform_specific_config
+startup --windows_enable_symlinks
+build:windows --enable_runfiles
+
+build --experimental_enable_bzlmod
+
+# This isn't currently the defaut in Bazel, but we enable it to test we'll be ready if/when it flips.
+build --incompatible_disallow_empty_glob
+
+# Required for cargo_build_script support before Bazel 7
+build --incompatible_merge_fixed_and_default_shell_env
+
+# Do not import the PATH etc. from the host environment
+common --incompatible_strict_action_env

examples/bazel_env/.envrc

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+# ^^^ make IDEs happy
+
+watch_file bazel-out/bazel_env-opt/bin/env/env/bin
+PATH_add bazel-out/bazel_env-opt/bin/env/env/bin
+if [[ ! -d bazel-out/bazel_env-opt/bin/env/env/bin ]]; then
+  log_error "ERROR[bazel_env.bzl]: Run 'bazel run //env:env' to regenerate bazel-out/bazel_env-opt/bin/env/env/bin"
+fi

examples/bazel_env/.gitignore

@@ -0,0 +1 @@
+/bazel-*

examples/bazel_env/BUILD.bazel

@@ -0,0 +1,50 @@
+"Tests for upstream wrappers."
+
+sh_test(
+    name = "upstream_cargo_test",
+    size = "small",
+    srcs = ["cargo_test.sh"],
+    args = [
+        "$(rlocationpath @rules_rust//tools/upstream_wrapper:cargo)",
+    ],
+    data = [
+        "Cargo.lock",
+        "Cargo.toml",
+        "//rust/hello_world:Cargo.toml",
+        "//rust/hello_world:src/main.rs",
+        "@rules_rust//tools/upstream_wrapper:cargo",
+    ],
+    deps = [
+        "@bazel_tools//tools/bash/runfiles",
+    ],
+)
+
+sh_test(
+    name = "upstream_rustc_test",
+    size = "small",
+    srcs = ["rustc_test.sh"],
+    args = [
+        "$(rlocationpath @rules_rust//tools/upstream_wrapper:rustc)",
+    ],
+    data = [
+        "@rules_rust//tools/upstream_wrapper:rustc",
+    ],
+    deps = [
+        "@bazel_tools//tools/bash/runfiles",
+    ],
+)
+
+sh_test(
+    name = "upstream_rustfmt_test",
+    size = "small",
+    srcs = ["rustfmt_test.sh"],
+    args = [
+        "$(rlocationpath @rules_rust//tools/upstream_wrapper:rustfmt)",
+    ],
+    data = [
+        "@rules_rust//tools/upstream_wrapper:rustfmt",
+    ],
+    deps = [
+        "@bazel_tools//tools/bash/runfiles",
+    ],
+)

examples/bazel_env/Cargo.toml

@@ -0,0 +1,5 @@
+[workspace]
+resolver = "2"
+members = [
+    "rust/hello_world"
+]

examples/bazel_env/MODULE.bazel

@@ -0,0 +1,44 @@
+"""bazelbuild/rules_rust - bazel_env/bzlmod example
+
+See https://github.com/buildbuddy-io/bazel_env.bzl.
+"""
+
+module(
+    name = "all_crate_deps_bzlmod_example",
+    version = "0.0.0",
+)
+
+bazel_dep(name = "platforms", version = "0.0.9")
+bazel_dep(
+    name = "rules_rust",
+    version = "0.0.0",
+)
+local_path_override(
+    module_name = "rules_rust",
+    path = "../..",
+)
+
+rust = use_extension("@rules_rust//rust:extensions.bzl", "rust")
+rust.toolchain(edition = "2021")
+use_repo(
+    rust,
+    "rust_toolchains",
+)
+
+register_toolchains("@rust_toolchains//:all")
+
+crate = use_extension(
+    "@rules_rust//crate_universe:extension.bzl",
+    "crate",
+)
+crate.from_cargo(
+    name = "crates",
+    cargo_lockfile = "//:Cargo.lock",
+    manifests = [
+        "//:Cargo.toml",
+        "//rust/hello_world:Cargo.toml",
+    ],
+)
+use_repo(crate, "crates")
+
+bazel_dep(name = "bazel_env.bzl", version = "0.1.1")

examples/bazel_env/README.md

@@ -0,0 +1,11 @@
+# rules_rust with bazel_env
+
+This example uses [bazel_env.bzl](https://github.com/buildbuddy-io/bazel_env.bzl) to
+provide `cargo`, `cargo-clippy`, `rustc` and `rustfmt` from the bazel toolchains
+to the user. They will be available directly in the PATH when the user
+enters this directory and has [direnv](https://direnv.net/) set up.
+
+Advantages:
+
+- The user doesn't have to install the toolchains themselves.
+- The tool versions will always match exactly those that bazel uses.

examples/bazel_env/WORKSPACE.bazel

@@ -0,0 +1 @@
+# Intentionally blank; using bzlmod

examples/bazel_env/WORKSPACE.bzlmod

@@ -0,0 +1 @@
+# Intentionally blank; enable strict mode for bzlmod

examples/bazel_env/cargo_test.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+
+# --- begin runfiles.bash initialization v3 ---
+# Copy-pasted from the Bazel Bash runfiles library v3.
+set -uo pipefail; set +e; f=bazel_tools/tools/bash/runfiles/runfiles.bash
+source "${RUNFILES_DIR:-/dev/null}/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "${RUNFILES_MANIFEST_FILE:-/dev/null}" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$0.runfiles/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.exe.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  { echo>&2 "ERROR: cannot find $f"; exit 1; }; f=; set -e
+# --- end runfiles.bash initialization v3 ---
+
+
+set -euo pipefail
+
+# MARK - Functions
+
+fail() {
+  echo >&2 "$@"
+  exit 1
+}
+
+# MARK - Args
+
+if [[ "$#" -lt 1 ]]; then
+  fail "Usage: $0 /path/to/bin <args>"
+fi
+CARGO="$(rlocation "$1")"
+
+# MARK - Test
+
+# simulate bazel run with setting BUILD_WORKING_DIRECTORY
+export BUILD_WORKING_DIRECTORY="$PWD" 
+
+# Run hello_world, invoking rustc
+OUTPUT="$("${CARGO}" run)"
+
+EXPECTED_OUTPUT="Hello, world!"
+[[ "${OUTPUT}" == "${EXPECTED_OUTPUT}" ]] ||
+  fail 'Expected "'"${EXPECTED_OUTPUT}"'", but was' "${OUTPUT}"
+
+# Crash tests, no error
+
+${CARGO} clippy ||
+  fail "couldn't execute \"cargo clippy\""

examples/bazel_env/env/BUILD.bazel

@@ -0,0 +1,13 @@
+load("@bazel_env.bzl", "bazel_env")
+
+package(default_visibility = ["//visibility:public"])
+
+bazel_env(
+    name = "env",
+    tools = {
+        "cargo": "@rules_rust//tools/upstream_wrapper:cargo",
+        "cargo-clippy": "@rules_rust//tools/upstream_wrapper:cargo_clippy",
+        "rustc": "@rules_rust//tools/upstream_wrapper:rustc",
+        "rustfmt": "@rules_rust//tools/upstream_wrapper:rustfmt",
+    },
+)

examples/bazel_env/rust/hello_world/BUILD.bazel

@@ -0,0 +1,15 @@
+load("@crates//:defs.bzl", "all_crate_deps")
+load("@rules_rust//rust:defs.bzl", "rust_binary")
+
+package(default_visibility = ["//visibility:public"])
+
+exports_files([
+    "Cargo.toml",
+    "src/main.rs",
+])
+
+rust_binary(
+    name = "hello_world",
+    srcs = ["src/main.rs"],
+    deps = all_crate_deps(normal = True),
+)

examples/bazel_env/rust/hello_world/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "hello_world"
+version = "0.0.0"
+edition = "2021"
+publish = false
+
+[lib]
+path = "/dev/null"

examples/bazel_env/rust/hello_world/src/main.rs

@@ -0,0 +1,17 @@
+// Copyright 2015 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+fn main() {
+    println!("Hello, world!");
+}

examples/bazel_env/rustc_test.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+
+# --- begin runfiles.bash initialization v3 ---
+# Copy-pasted from the Bazel Bash runfiles library v3.
+set -uo pipefail; set +e; f=bazel_tools/tools/bash/runfiles/runfiles.bash
+source "${RUNFILES_DIR:-/dev/null}/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "${RUNFILES_MANIFEST_FILE:-/dev/null}" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$0.runfiles/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.exe.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  { echo>&2 "ERROR: cannot find $f"; exit 1; }; f=; set -e
+# --- end runfiles.bash initialization v3 ---
+
+
+set -euo pipefail
+
+# MARK - Functions
+
+fail() {
+  echo >&2 "$@"
+  exit 1
+}
+
+# MARK - Args
+
+if [[ "$#" -lt 1 ]]; then
+  fail "Usage: $0 /path/to/bin <args>"
+fi
+RUSTC="$(rlocation "$1")"
+
+# MARK - Test
+DIR=$(mktemp -d "rustc-test-XXXXXXX")
+
+set -x
+echo "fn main() {}" >"$DIR/main.rs"
+cd "$DIR"
+# simulate bazel run with setting BUILD_WORKING_DIRECTORY
+export BUILD_WORKING_DIRECTORY="$PWD" 
+"$RUSTC" "main.rs" || 
+  fail "Couldn't compile main.rs"

examples/bazel_env/rustfmt_test.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+
+# --- begin runfiles.bash initialization v3 ---
+# Copy-pasted from the Bazel Bash runfiles library v3.
+set -uo pipefail; set +e; f=bazel_tools/tools/bash/runfiles/runfiles.bash
+source "${RUNFILES_DIR:-/dev/null}/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "${RUNFILES_MANIFEST_FILE:-/dev/null}" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$0.runfiles/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.exe.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  { echo>&2 "ERROR: cannot find $f"; exit 1; }; f=; set -e
+# --- end runfiles.bash initialization v3 ---
+
+
+set -euo pipefail
+
+# MARK - Functions
+
+fail() {
+  echo >&2 "$@"
+  exit 1
+}
+
+# MARK - Args
+
+if [[ "$#" -lt 1 ]]; then
+  fail "Usage: $0 /path/to/bin <args>"
+fi
+RUSTFMT="$(rlocation "$1")"
+
+# MARK - Test
+
+# simulate bazel run with setting BUILD_WORKING_DIRECTORY
+export BUILD_WORKING_DIRECTORY="$PWD" 
+
+OUTPUT="$(echo -e "fn main() {\n\n}" | "$RUSTFMT")"
+
+# without newlines in body
+EXPECTED_OUTPUT="fn main() {}"
+[[ "${OUTPUT}" == "${EXPECTED_OUTPUT}" ]] ||
+  fail 'Expected "'"${EXPECTED_OUTPUT}"'", but was' "${OUTPUT}"