Allow --document-private-items to accept =yes|no

Fixes rust-lang#7963.

Previously, --document-private-items was only a 'truthy' flag,
and was enabled in rust-lang#7593 for binary targets by default. However,
this prevented any means of *disabling* this functionality for
binary targets, hence rust-lang#7963.

This change does a few things. It first adds a new argument
parser type called `yesno_flag()` that is a wrapper around
a few `clap::Arg` settings to use the built-in `BoolishValueParser`
in a way that allows for the `--flag` to return `true`, as well
as an optional `=no` or `=yes` (or `=1`, `=off`, etc.) to explicitly
set it to `true` or `false`.

Then, the internal field for passing the private member documentation
flag to rustdoc was changed to an `Option<bool>` to treat `None`
as the automatic project type detection, and a `Some` value to
override the behavior outright.

This change should be entirely backwards compatible.

src/bin/cargo/commands/doc.rs

@@ -21,7 +21,10 @@ pub fn cli() -> App {
             "no-deps",
             "Don't build documentation for dependencies",
         ))
-        .arg(flag("document-private-items", "Document private items"))
+        .arg(yesno_flag(
+            "document-private-items",
+            "Document private items (the default for binaries)",
+        ))
         .arg_jobs()
         .arg_targets_lib_bin_example(
             "Document only this package's library",
@@ -50,7 +53,9 @@ pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {
     };
     let mut compile_opts =
         args.compile_options(config, mode, Some(&ws), ProfileChecking::Custom)?;
-    compile_opts.rustdoc_document_private_items = args.flag("document-private-items");
+
+    compile_opts.rustdoc_document_private_items =
+        args.get_one::<bool>("document-private-items").copied();
 
     let doc_opts = DocOptions {
         open_result: args.flag("open"),

src/cargo/ops/cargo_compile.rs

@@ -75,9 +75,11 @@ pub struct CompileOptions {
     pub target_rustc_crate_types: Option<Vec<String>>,
     /// Extra arguments passed to all selected targets for rustdoc.
     pub local_rustdoc_args: Option<Vec<String>>,
-    /// Whether the `--document-private-items` flags was specified and should
-    /// be forwarded to `rustdoc`.
-    pub rustdoc_document_private_items: bool,
+    /// Whether either the `--document-private-items` flag was specified, and
+    /// if so, if that argument should be forwarded to `rustdoc`. `None` indicates
+    /// that the behavior should be decided based on the target type - either public-only
+    /// for libraries, or private items for binaries.
+    pub rustdoc_document_private_items: Option<bool>,
     /// Whether the build process should check the minimum Rust version
     /// defined in the cargo metadata for a crate.
     pub honor_rust_version: bool,
@@ -98,7 +100,7 @@ impl CompileOptions {
             target_rustc_args: None,
             target_rustc_crate_types: None,
             local_rustdoc_args: None,
-            rustdoc_document_private_items: false,
+            rustdoc_document_private_items: None,
             honor_rust_version: true,
         })
     }
@@ -620,7 +622,7 @@ pub fn create_bcx<'a, 'cfg>(
             // Add `--document-private-items` rustdoc flag if requested or if
             // the target is a binary. Binary crates get their private items
             // documented by default.
-            if rustdoc_document_private_items || unit.target.is_bin() {
+            if rustdoc_document_private_items.unwrap_or(unit.target.is_bin()) {
                 let mut args = extra_args.take().unwrap_or_default();
                 args.push("--document-private-items".into());
                 if unit.target.is_bin() {

src/cargo/ops/cargo_package.rs

@@ -830,7 +830,7 @@ fn run_verify(
             target_rustc_args: rustc_args,
             target_rustc_crate_types: None,
             local_rustdoc_args: None,
-            rustdoc_document_private_items: false,
+            rustdoc_document_private_items: None,
             honor_rust_version: true,
         },
         &exec,

src/cargo/util/command_prelude.rs

@@ -268,6 +268,20 @@ pub fn flag(name: &'static str, help: &'static str) -> Arg<'static> {
         .action(ArgAction::SetTrue)
 }
 
+pub fn yesno_flag(name: &'static str, help: &'static str) -> Arg<'static> {
+    Arg::new(name)
+        .long(name)
+        .help(help)
+        .value_name("yes|no")
+        .value_parser(clap::builder::BoolishValueParser::new())
+        .hide_possible_values(true)
+        .min_values(0)
+        .takes_value(true)
+        .multiple_values(false)
+        .require_equals(true)
+        .default_missing_value("yes")
+}
+
 pub fn opt(name: &'static str, help: &'static str) -> Arg<'static> {
     Arg::new(name).long(name).help(help)
 }
@@ -610,7 +624,7 @@ pub trait ArgMatchesExt {
             target_rustc_args: None,
             target_rustc_crate_types: None,
             local_rustdoc_args: None,
-            rustdoc_document_private_items: false,
+            rustdoc_document_private_items: None,
             honor_rust_version: !self.flag("ignore-rust-version"),
         };
 

src/doc/man/cargo-doc.md

@@ -32,7 +32,7 @@ option.
 Do not build documentation for dependencies.
 {{/option}}
 
-{{#option "`--document-private-items`" }}
+{{#option "`--document-private-items`[=_yes|no_]" }}
 Include non-public items in the documentation. This will be enabled by default if documenting a binary target.
 {{/option}}
 

src/doc/man/generated_txt/cargo-doc.txt

@@ -22,7 +22,7 @@ OPTIONS
        --no-deps
            Do not build documentation for dependencies.
 
-       --document-private-items
+       --document-private-items[=yes|no]
            Include non-public items in the documentation. This will be enabled
            by default if documenting a binary target.
 

src/doc/src/commands/cargo-doc.md

@@ -32,7 +32,7 @@ option.</dd>
 <dd class="option-desc">Do not build documentation for dependencies.</dd>
 
 
-<dt class="option-term" id="option-cargo-doc---document-private-items"><a class="option-anchor" href="#option-cargo-doc---document-private-items"></a><code>--document-private-items</code></dt>
+<dt class="option-term" id="option-cargo-doc---document-private-items[=yes|no]"><a class="option-anchor" href="#option-cargo-doc---document-private-items[=yes|no]"></a><code>--document-private-items</code>[=<em>yes|no</em>]</dt>
 <dd class="option-desc">Include non-public items in the documentation. This will be enabled by default if documenting a binary target.</dd>
 
 

src/etc/_cargo

@@ -125,7 +125,7 @@ _cargo() {
                 doc | d)
                     _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
                         '--no-deps[do not build docs for dependencies]' \
-                        '--document-private-items[include non-public items in the documentation]' \
+                        '--document-private-items'{--document-private-items=}'[include non-public items in the documentation]:bool:_cargo_yesno' \
                         '--open[open docs in browser after the build]' \
                         '(-p --package)'{-p+,--package=}'[specify package to document]:package:_cargo_package_names' \
                         '--release[build artifacts in release mode, with optimizations]' \
@@ -261,7 +261,7 @@ _cargo() {
 
                 rustdoc)
                     _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
-                        '--document-private-items[include non-public items in the documentation]' \
+                        '--document-private-items'{--document-private-items=}'[include non-public items in the documentation]:bool:_cargo_yesno' \
                         '--open[open the docs in a browser after the operation]' \
                         '(-p --package)'{-p+,--package=}'[specify package to document]:package:_cargo_package_names' \
                         '--release[build artifacts in release mode, with optimizations]' \
@@ -444,4 +444,8 @@ _cargo_example_names() {
     fi
 }
 
+_cargo_yesno() {
+    _values 'yes|no' yes no
+}
+
 _cargo

src/etc/man/cargo-doc.1

@@ -26,7 +26,7 @@ option.
 Do not build documentation for dependencies.
 .RE
 .sp
-\fB\-\-document\-private\-items\fR
+\fB\-\-document\-private\-items\fR[=\fIyes|no\fR]
 .RS 4
 Include non\-public items in the documentation. This will be enabled by default if documenting a binary target.
 .RE

tests/testsuite/doc.rs

@@ -1922,6 +1922,58 @@ fn bin_private_items() {
     assert!(p.root().join("target/doc/foo/foo_mod/index.html").is_file());
 }
 
+#[cargo_test]
+fn bin_private_items_disable() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                authors = []
+            "#,
+        )
+        .file(
+            "src/main.rs",
+            "
+            pub fn foo_pub() {}
+            fn foo_priv() {}
+            struct FooStruct;
+            enum FooEnum {}
+            trait FooTrait {}
+            type FooType = u32;
+            mod foo_mod {}
+
+        ",
+        )
+        .build();
+
+    p.cargo("doc --document-private-items=no")
+        .with_stderr(
+            "\
+[DOCUMENTING] foo v0.0.1 ([CWD])
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
+",
+        )
+        .run();
+
+    assert!(p.root().join("target/doc/foo/index.html").is_file());
+    assert!(p.root().join("target/doc/foo/fn.foo_pub.html").is_file());
+    assert!(!p.root().join("target/doc/foo/fn.foo_priv.html").is_file());
+    assert!(!p
+        .root()
+        .join("target/doc/foo/struct.FooStruct.html")
+        .is_file());
+    assert!(!p.root().join("target/doc/foo/enum.FooEnum.html").is_file());
+    assert!(!p
+        .root()
+        .join("target/doc/foo/trait.FooTrait.html")
+        .is_file());
+    assert!(!p.root().join("target/doc/foo/type.FooType.html").is_file());
+    assert!(!p.root().join("target/doc/foo/foo_mod/index.html").is_file());
+}
+
 #[cargo_test]
 fn bin_private_items_deps() {
     let p = project()