Doc specific features

src/bin/cargo/commands/doc.rs

@@ -1,6 +1,7 @@
 use crate::command_prelude::*;
 
 use cargo::ops::{self, DocOptions};
+use cargo::util;
 
 pub fn cli() -> App {
     subcommand("doc")
@@ -56,6 +57,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
     let mut compile_opts =
         args.compile_options(config, mode, Some(&ws), ProfileChecking::Checked)?;
     compile_opts.rustdoc_document_private_items = args.is_present("document-private-items");
+    util::get_features_for("doc", &mut compile_opts, &ws)?;
 
     let doc_opts = DocOptions {
         open_result: args.is_present("open"),

src/cargo/util/build_specific.rs

@@ -0,0 +1,58 @@
+use crate::core::Workspace;
+use crate::ops::CompileOptions;
+use crate::util::{CliError, CliResult};
+
+use failure;
+use toml::Value;
+
+/// Check if specific features are available under `[package.metadata.X]` (`X`
+/// being one of the supported types).
+///
+/// For now, it only supports it for "doc" build.
+pub fn get_features_for(
+    r#for: &str,
+    compile_opts: &mut CompileOptions<'_>,
+    ws: &Workspace<'_>,
+) -> CliResult {
+    match r#for {
+        "doc" => {} // If other features-specific kind are added, they should be put here.
+        _ => return Ok(()),
+    }
+    let packages = match compile_opts.spec.get_packages(ws) {
+        Ok(p) => p,
+        _ => return Ok(()),
+    };
+    for package in packages {
+        if let Some(Value::Table(ref metadata)) = package.manifest().custom_metadata() {
+            if let Some(ref doc) = metadata.get(r#for) {
+                match doc.get("features") {
+                    Some(Value::Array(ref features)) => {
+                        let mut additional_features = Vec::with_capacity(2);
+
+                        for feature in features.iter() {
+                            if let Value::String(s) = feature {
+                                additional_features.push(s.clone());
+                            } else {
+                                Err(CliError::new(
+                                    failure::format_err!(
+                                        "Only strings are allowed in `features` array"
+                                    ),
+                                    1,
+                                ))?
+                            }
+                        }
+                        compile_opts
+                            .features
+                            .extend(additional_features.into_iter());
+                    }
+                    Some(_) => Err(CliError::new(
+                        failure::format_err!("`features` should be an array"),
+                        1,
+                    ))?,
+                    None => {}
+                }
+            }
+        }
+    }
+    Ok(())
+}

src/cargo/util/mod.rs

@@ -1,5 +1,6 @@
 use std::time::Duration;
 
+pub use self::build_specific::get_features_for;
 pub use self::canonical_url::CanonicalUrl;
 pub use self::config::{homedir, Config, ConfigValue};
 pub use self::dependency_queue::DependencyQueue;
@@ -28,6 +29,7 @@ pub use self::workspace::{
     print_available_tests,
 };
 
+pub mod build_specific;
 mod canonical_url;
 pub mod command_prelude;
 pub mod config;

tests/testsuite/doc_features_specific.rs

@@ -0,0 +1,144 @@
+//! Tests for "doc"-specific features.
+
+use cargo_test_support::project;
+
+#[cargo_test]
+fn bad1() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "0.1.0"
+            authors = []
+
+            [package.metadata.doc]
+            features = "foo"
+        "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+    p.cargo("doc -v")
+        .with_status(1)
+        .with_stderr("error: `features` should be an array")
+        .run();
+}
+
+#[cargo_test]
+fn bad2() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "0.1.0"
+            authors = []
+
+            [package.metadata.doc]
+            features = [12]
+        "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+    p.cargo("doc -v")
+        .with_status(1)
+        .with_stderr("error: Only strings are allowed in `features` array")
+        .run();
+}
+
+#[cargo_test]
+fn bad3() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "0.1.0"
+            authors = []
+
+            [package.metadata.doc]
+            features = ["foo"]
+        "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+    p.cargo("doc -v")
+        .with_status(101)
+        .with_stderr(
+            "error: Package `foo v0.1.0 ([..])` does not \
+             have these features: `foo`",
+        )
+        .run();
+}
+
+#[cargo_test]
+fn success() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "0.1.0"
+            authors = []
+
+            [features]
+            foo = []
+
+            [package.metadata.doc]
+            features = ["foo"]
+        "#,
+        )
+        .file(
+            "src/lib.rs",
+            r#"
+            #[cfg(feature = "foo")]
+            compile_error!("foo is crazy!");
+        "#,
+        )
+        .build();
+    p.cargo("doc -v")
+        .with_status(101)
+        .with_stderr_contains(
+            "\
+3 |             compile_error!(\"foo is crazy!\");
+  |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: Compilation failed, aborting rustdoc
+
+error: aborting due to 2 previous errors",
+        )
+        .run();
+}
+
+#[cargo_test]
+fn success2() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "0.0.0"
+            authors = []
+
+            [features]
+            foo = []
+
+            [package.metadata.doc]
+            features = ["foo"]
+        "#,
+        )
+        .file(
+            "src/lib.rs",
+            r#"
+            #[cfg(feature = "foo")]
+            compile_error!("foo is crazy!");
+        "#,
+        )
+        .build();
+    p.cargo("build -v").with_status(0).run();
+}

tests/testsuite/main.rs

@@ -38,6 +38,7 @@ mod death;
 mod dep_info;
 mod directory;
 mod doc;
+mod doc_features_specific;
 mod edition;
 mod features;
 mod fetch;