examples/bazel_env: Add an example

...and simplify target names of wrappers

examples/bazel_env/.bazelrc

@@ -0,0 +1,12 @@
+# 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

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 +1,9 @@
+load("@crates//:defs.bzl", "all_crate_deps")
+
+package(default_visibility = ["//visibility:public"])
+
+rust_binary(
+    name = "all_crate_deps",
+    srcs = ["src/main.rs"],
+    deps = all_crate_deps(normal = True),
+)

examples/bazel_env/Cargo.toml

@@ -0,0 +1,12 @@
+[workspace]
+[package]
+name = "all_crate_deps"
+version = "0.0.0"
+edition = "2021"
+publish = false
+
+[lib]
+path = "/dev/null"
+
+[dependencies]
+anyhow = "1.0.79"

examples/bazel_env/MODULE.bazel

@@ -0,0 +1,42 @@
+"""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"],
+)
+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/all_crate_deps_test.sh

@@ -0,0 +1,35 @@
+#!/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 [[ "$#" -ne 1 ]]; then
+  fail "Usage: $0 /path/to/hello_world"
+fi
+HELLO_WORLD="$(rlocation "$1")"
+
+# MARK - Test
+
+OUTPUT="$("${HELLO_WORLD}")"
+[[ "${OUTPUT}" == "Hello, world!" ]] ||
+  fail 'Expected "Hello, world!", but was' "${OUTPUT}"

examples/bazel_env/env/BUILD.bazel

@@ -0,0 +1,11 @@
+load("@bazel_env.bzl", "bazel_env")
+
+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/src/main.rs

@@ -0,0 +1,18 @@
+// 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() -> anyhow::Result<()> {
+    println!("Hello, world!");
+    Ok(())
+}

tools/rustfmt/BUILD.bazel

@@ -36,7 +36,7 @@ rust_library(
 alias(
     name = "rustfmt",
     actual = ":target_aware_rustfmt",
-    deprecation = "Prefer //tools/rustfmt:target_aware_rustfmt",
+    deprecation = "Prefer //tools/upstream_wrapper:rustfmt",
     visibility = ["//visibility:public"],
 )
 
@@ -88,7 +88,7 @@ rust_clippy(
 # Deprecated but present for compatibility.
 alias(
     name = "upstream_rustfmt",
-    actual = "//tools/upstream_wrapper:upstream_rustfmt",
-    deprecation = "Prefer //tools/upstream_wrapper:upstream_rustfmt",
+    actual = "//tools/upstream_wrapper:rustfmt",
+    deprecation = "Prefer //tools/upstream_wrapper:rustfmt",
     visibility = ["//visibility:public"],
 )

tools/upstream_wrapper/BUILD.bazel

@@ -8,11 +8,11 @@ tools = {
     "rustfmt": "//rust/toolchain:current_rustfmt_toolchain_for_target",
 }
 
-# This is a small wrapper around the raw upstream binary which can be `bazel run`.
+# Create wrappers around the tools that can be used `bazel run` or bazel_env.
 
 [
     rust_binary(
-        name = "upstream_{}".format(tool_name),
+        name = tool_name,
         srcs = [
             "src/main.rs",
         ],