add rustdoc feature support

rust/private/providers.bzl

@@ -36,6 +36,7 @@ CrateInfo = provider(
         "rustc_rmeta_output": "File: The rmeta file produced for this crate. It is optional.",
         "srcs": "depset[File]: All source Files that are part of the crate.",
         "std_dylib": "File: libstd.so file",
+        "crate_features": "[str]: A list of feature enabled for this crate.",
         "type": (
             "str: The type of this crate " +
             "(see [rustc --crate-type](https://doc.rust-lang.org/rustc/command-line-arguments.html#--crate-type-a-list-of-types-of-crates-for-the-compiler-to-emit))."

rust/private/rust.bzl

@@ -206,6 +206,7 @@ def _rust_library_common(ctx, crate_type):
             compile_data = depset(compile_data),
             compile_data_targets = depset(ctx.attr.compile_data),
             owner = ctx.label,
+            crate_features = ctx.attr.crate_features,
         ),
     )
 
@@ -258,6 +259,7 @@ def _rust_binary_impl(ctx):
             compile_data = depset(compile_data),
             compile_data_targets = depset(ctx.attr.compile_data),
             owner = ctx.label,
+            crate_features = ctx.attr.crate_features,
         ),
     )
 
@@ -422,6 +424,7 @@ def _rust_test_impl(ctx):
             compile_data = depset(compile_data),
             compile_data_targets = depset(ctx.attr.compile_data),
             owner = ctx.label,
+            crate_features = [],
         )
 
     providers = rustc_compile_action(

rust/private/rustdoc.bzl

@@ -236,6 +236,9 @@ def _rust_doc_impl(ctx):
 
     rustdoc_flags.extend(ctx.attr.rustdoc_flags)
 
+    if ctx.attr.include_features:
+        rustdoc_flags.extend(["--cfg=feature=\"{}\"".format(feature) for feature in crate_info.crate_features])
+
     action = rustdoc_compile_action(
         ctx = ctx,
         toolchain = find_toolchain(ctx),
@@ -350,6 +353,10 @@ rust_doc = rule(
                 file of arguments to rustc: `@$(location //package:target)`.
             """),
         ),
+        "include_features": attr.bool(
+            doc = "Include the features defined by `crate_features` when building the doc tests.",
+            default = True,
+        ),
         "_dir_zipper": attr.label(
             doc = "A tool that orchestrates the creation of zip archives for rustdoc outputs.",
             default = Label("//rust/private/rustdoc/dir_zipper"),

rust/private/rustdoc_test.bzl

@@ -129,6 +129,7 @@ def _rust_doc_test_impl(ctx):
         compile_data = crate.compile_data,
         compile_data_targets = crate.compile_data_targets,
         wrapped_crate_type = crate.type,
+        crate_features = crate.crate_features,
         owner = ctx.label,
     )
 
@@ -150,6 +151,9 @@ def _rust_doc_test_impl(ctx):
         "--test",
     ]
 
+    if ctx.attr.include_features:
+        rustdoc_flags.extend(["--cfg=feature=\"{}\"".format(feature) for feature in crate_info.crate_features])
+
     action = rustdoc_compile_action(
         ctx = ctx,
         toolchain = toolchain,
@@ -228,6 +232,10 @@ rust_doc_test = rule(
             default = Label("//rust/private/rustdoc:rustdoc_test_writer"),
             executable = True,
         ),
+        "include_features": attr.bool(
+            doc = "Include the features defined by `crate_features` when building the doc tests.",
+            default = True,
+        ),
     },
     test = True,
     fragments = ["cpp"],

test/unit/rustdoc/rustdoc_features.rs

@@ -0,0 +1,29 @@
+// Copyright 2022 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.
+
+#![cfg_attr(not(no_feature_test), deny(rustdoc::broken_intra_doc_links))]
+#![cfg_attr(no_feature_test, allow(rustdoc::broken_intra_doc_links))]
+
+//!
+//! Checkout [inc]
+//!
+
+#[cfg(all(no_feature_test, feature = "docs"))]
+compiler_error!("cannot have both no_feature_test and feature=\"docs\" enabled");
+
+/// Increments the input.
+#[cfg(feature = "docs")]
+pub fn inc(n: u32) -> u32 {
+    n + 1
+}

test/unit/rustdoc/rustdoc_unit_test.bzl

@@ -97,6 +97,30 @@ def _rustdoc_for_bin_with_transitive_proc_macro_test_impl(ctx):
 
     return analysistest.end(env)
 
+def _rustdoc_for_lib_with_features_test_impl(ctx):
+    env = analysistest.begin(ctx)
+    tut = analysistest.target_under_test(env)
+
+    _common_rustdoc_checks(env, tut)
+
+    action = _get_rustdoc_action(env, tut)
+
+    assert_argv_contains(env, action, "--cfg=feature=\"docs\"")
+
+    return analysistest.end(env)
+
+def _rustdoc_for_lib_without_features_test_impl(ctx):
+    env = analysistest.begin(ctx)
+    tut = analysistest.target_under_test(env)
+
+    _common_rustdoc_checks(env, tut)
+
+    action = _get_rustdoc_action(env, tut)
+
+    assert_argv_contains_prefix_not(env, action, "--cfg=feature")
+
+    return analysistest.end(env)
+
 def _rustdoc_for_lib_with_cc_lib_test_impl(ctx):
     env = analysistest.begin(ctx)
     tut = analysistest.target_under_test(env)
@@ -164,6 +188,8 @@ rustdoc_for_lib_with_proc_macro_in_docs_test = analysistest.make(_rustdoc_for_li
 rustdoc_for_bin_with_transitive_proc_macro_test = analysistest.make(_rustdoc_for_bin_with_transitive_proc_macro_test_impl)
 rustdoc_for_lib_with_cc_lib_test = analysistest.make(_rustdoc_for_lib_with_cc_lib_test_impl)
 rustdoc_with_args_test = analysistest.make(_rustdoc_with_args_test_impl)
+rustdoc_for_lib_with_features_test = analysistest.make(_rustdoc_for_lib_with_features_test_impl)
+rustdoc_for_lib_without_features_test = analysistest.make(_rustdoc_for_lib_without_features_test_impl)
 rustdoc_zip_output_test = analysistest.make(_rustdoc_zip_output_test_impl)
 rustdoc_with_json_error_format_test = analysistest.make(_rustdoc_with_json_error_format_test_impl, config_settings = {
     str(Label("//rust/settings:error_format")): "json",
@@ -283,6 +309,34 @@ def _define_targets():
         crate_features = ["with_proc_macro"],
     )
 
+    _target_maker(
+        rust_library,
+        name = "lib_with_features",
+        srcs = ["rustdoc_features.rs"],
+        crate_features = ["docs"],
+    )
+
+    rust_doc(
+        name = "rustdoc_lib_with_features",
+        crate = ":lib_with_features",
+    )
+
+    _target_maker(
+        rust_library,
+        name = "lib_without_features",
+        srcs = ["rustdoc_features.rs"],
+        crate_features = ["docs"],
+    )
+
+    rust_doc(
+        name = "rustdoc_lib_without_features",
+        crate = ":lib_with_features",
+        include_features = False,
+        rustdoc_flags = [
+            "--cfg=no_feature_test"
+        ]
+    )
+
     cc_library(
         name = "cc_lib",
         hdrs = ["rustdoc.h"],
@@ -424,6 +478,16 @@ def rustdoc_test_suite(name):
         target_under_test = ":lib_with_cc_doc",
     )
 
+    rustdoc_for_lib_with_features_test(
+        name = "rustdoc_for_lib_with_features_test",
+        target_under_test = ":rustdoc_lib_with_features",
+    )
+
+    rustdoc_for_lib_without_features_test(
+        name = "rustdoc_for_lib_without_features_test",
+        target_under_test = ":rustdoc_lib_without_features",
+    )
+
     rustdoc_with_args_test(
         name = "rustdoc_with_args_test",
         target_under_test = ":rustdoc_with_args",
@@ -455,6 +519,8 @@ def rustdoc_test_suite(name):
             ":rustdoc_for_lib_with_proc_macro_in_docs_test",
             ":rustdoc_for_lib_with_proc_macro_test",
             ":rustdoc_for_lib_with_cc_lib_test",
+            ":rustdoc_for_lib_with_features_test",
+            ":rustdoc_for_lib_without_features_test",
             ":rustdoc_with_args_test",
             ":rustdoc_with_json_error_format_test",
             ":rustdoc_zip_output_test",