feat: Add "-Zpublic-denpendency" for public-dependency feature.

src/cargo/core/compiler/mod.rs

@@ -89,7 +89,7 @@ use crate::core::compiler::future_incompat::FutureIncompatReport;
 pub use crate::core::compiler::unit::{Unit, UnitInterner};
 use crate::core::manifest::TargetSourcePath;
 use crate::core::profiles::{PanicStrategy, Profile, StripInner};
-use crate::core::{Feature, PackageId, Target, Verbosity};
+use crate::core::{PackageId, Target, Verbosity};
 use crate::util::errors::{CargoResult, VerboseError};
 use crate::util::interning::InternedString;
 use crate::util::machine_message::{self, Message};
@@ -1437,15 +1437,7 @@ pub fn extern_args(
         |dep: &UnitDep, extern_crate_name: InternedString, noprelude: bool| -> CargoResult<()> {
             let mut value = OsString::new();
             let mut opts = Vec::new();
-            if unit
-                .pkg
-                .manifest()
-                .unstable_features()
-                .require(Feature::public_dependency())
-                .is_ok()
-                && !dep.public
-                && unit.target.is_lib()
-            {
+            if !dep.public && unit.target.is_lib() {
                 opts.push("priv");
                 *unstable_opts = true;
             }

src/cargo/core/features.rs

@@ -458,9 +458,6 @@ features! {
     /// Declarative build scripts.
     (unstable, metabuild, "", "reference/unstable.html#metabuild"),
 
-    /// Specifying the 'public' attribute on dependencies.
-    (unstable, public_dependency, "", "reference/unstable.html#public-dependency"),
-
     /// Allow to specify profiles other than 'dev', 'release', 'test', etc.
     (stable, named_profiles, "1.57", "reference/profiles.html#custom-profiles"),
 
@@ -764,6 +761,7 @@ unstable_cli_options!(
     panic_abort_tests: bool = ("Enable support to run tests with -Cpanic=abort"),
     precise_pre_release: bool = ("Enable pre-release versions to be selected with `update --precise`"),
     profile_rustflags: bool = ("Enable the `rustflags` option in profiles in .cargo/config.toml file"),
+    public_dependency: bool = ("Enable public-dependency to allow marking dependencies as public/private"),
     publish_timeout: bool = ("Enable the `publish.timeout` key in .cargo/config.toml file"),
     rustdoc_map: bool = ("Allow passing external documentation mappings to rustdoc"),
     rustdoc_scrape_examples: bool = ("Allows Rustdoc to scrape code examples from reverse-dependencies"),
@@ -1140,6 +1138,7 @@ impl CliUnstable {
             "mtime-on-use" => self.mtime_on_use = parse_empty(k, v)?,
             "no-index-update" => self.no_index_update = parse_empty(k, v)?,
             "panic-abort-tests" => self.panic_abort_tests = parse_empty(k, v)?,
+            "public-dependency" => self.public_dependency = parse_empty(k, v)?,
             "profile-rustflags" => self.profile_rustflags = parse_empty(k, v)?,
             "precise-pre-release" => self.precise_pre_release = parse_empty(k, v)?,
             "trim-paths" => self.trim_paths = parse_empty(k, v)?,

src/cargo/core/workspace.rs

@@ -449,7 +449,6 @@ impl<'cfg> Workspace<'cfg> {
                             // NOTE: Since we use ConfigRelativePath, this root isn't used as
                             // any relative paths are resolved before they'd be joined with root.
                             Path::new("unused-relative-path"),
-                            self.unstable_features(),
                             /* kind */ None,
                         )
                     })

src/cargo/ops/cargo_package.rs

@@ -10,8 +10,8 @@ use crate::core::compiler::{BuildConfig, CompileMode, DefaultExecutor, Executor}
 use crate::core::manifest::Target;
 use crate::core::resolver::CliFeatures;
 use crate::core::{registry::PackageRegistry, resolver::HasDevUnits};
-use crate::core::{Feature, Shell, Verbosity, Workspace};
 use crate::core::{Package, PackageId, PackageSet, Resolve, SourceId};
+use crate::core::{Shell, Verbosity, Workspace};
 use crate::sources::PathSource;
 use crate::util::cache_lock::CacheLockMode;
 use crate::util::config::JobsConfig;
@@ -910,20 +910,7 @@ fn run_verify(
     let new_pkg = src.root_package()?;
     let pkg_fingerprint = hash_all(&dst)?;
     let ws = Workspace::ephemeral(new_pkg, config, None, true)?;
-
-    let rustc_args = if pkg
-        .manifest()
-        .unstable_features()
-        .require(Feature::public_dependency())
-        .is_ok()
-    {
-        // FIXME: Turn this on at some point in the future
-        //Some(vec!["-D exported_private_dependencies".to_string()])
-        Some(vec![])
-    } else {
-        None
-    };
-
+    let rustc_args = Some(vec![]);
     let exec: Arc<dyn Executor> = Arc::new(DefaultExecutor);
     ops::compile_with_exec(
         &ws,

src/cargo/util/toml/mod.rs

@@ -9,8 +9,8 @@ use crate::AlreadyPrintedError;
 use anyhow::{anyhow, bail, Context as _};
 use cargo_platform::Platform;
 use cargo_util::paths;
-use cargo_util_schemas::manifest;
-use cargo_util_schemas::manifest::RustVersion;
+use cargo_util_schemas::manifest::{self, InheritableDependency};
+use cargo_util_schemas::manifest::{RustVersion, TomlDependency};
 use itertools::Itertools;
 use lazycell::LazyCell;
 use pathdiff::diff_paths;
@@ -105,61 +105,62 @@ fn read_manifest_from_str(
 
     let mut unused = BTreeSet::new();
     let deserializer = toml::de::Deserializer::new(contents);
-    let manifest: manifest::TomlManifest = match serde_ignored::deserialize(deserializer, |path| {
-        let mut key = String::new();
-        stringify(&mut key, &path);
-        unused.insert(key);
-    }) {
-        Ok(manifest) => manifest,
-        Err(e) => {
-            let Some(span) = e.span() else {
-                return Err(e.into());
-            };
+    let mut manifest: manifest::TomlManifest =
+        match serde_ignored::deserialize(deserializer, |path| {
+            let mut key = String::new();
+            stringify(&mut key, &path);
+            unused.insert(key);
+        }) {
+            Ok(manifest) => manifest,
+            Err(e) => {
+                let Some(span) = e.span() else {
+                    return Err(e.into());
+                };
 
-            let (line_num, column) = translate_position(&contents, span.start);
-            let source_start = contents[0..span.start]
-                .rfind('\n')
-                .map(|s| s + 1)
-                .unwrap_or(0);
-            let source_end = contents[span.end - 1..]
-                .find('\n')
-                .map(|s| s + span.end)
-                .unwrap_or(contents.len());
-            let source = &contents[source_start..source_end];
-            // Make sure we don't try to highlight past the end of the line,
-            // but also make sure we are highlighting at least one character
-            let highlight_end = (column + contents[span].chars().count())
-                .min(source.len())
-                .max(column + 1);
-            // Get the path to the manifest, relative to the cwd
-            let manifest_path = diff_paths(manifest_file, config.cwd())
-                .unwrap_or_else(|| manifest_file.to_path_buf())
-                .display()
-                .to_string();
-            let snippet = Snippet {
-                title: Some(Annotation {
-                    id: None,
-                    label: Some(e.message()),
-                    annotation_type: AnnotationType::Error,
-                }),
-                footer: vec![],
-                slices: vec![Slice {
-                    source: &source,
-                    line_start: line_num + 1,
-                    origin: Some(manifest_path.as_str()),
-                    annotations: vec![SourceAnnotation {
-                        range: (column, highlight_end),
-                        label: "",
+                let (line_num, column) = translate_position(&contents, span.start);
+                let source_start = contents[0..span.start]
+                    .rfind('\n')
+                    .map(|s| s + 1)
+                    .unwrap_or(0);
+                let source_end = contents[span.end - 1..]
+                    .find('\n')
+                    .map(|s| s + span.end)
+                    .unwrap_or(contents.len());
+                let source = &contents[source_start..source_end];
+                // Make sure we don't try to highlight past the end of the line,
+                // but also make sure we are highlighting at least one character
+                let highlight_end = (column + contents[span].chars().count())
+                    .min(source.len())
+                    .max(column + 1);
+                // Get the path to the manifest, relative to the cwd
+                let manifest_path = diff_paths(manifest_file, config.cwd())
+                    .unwrap_or_else(|| manifest_file.to_path_buf())
+                    .display()
+                    .to_string();
+                let snippet = Snippet {
+                    title: Some(Annotation {
+                        id: None,
+                        label: Some(e.message()),
                         annotation_type: AnnotationType::Error,
+                    }),
+                    footer: vec![],
+                    slices: vec![Slice {
+                        source: &source,
+                        line_start: line_num + 1,
+                        origin: Some(manifest_path.as_str()),
+                        annotations: vec![SourceAnnotation {
+                            range: (column, highlight_end),
+                            label: "",
+                            annotation_type: AnnotationType::Error,
+                        }],
+                        fold: false,
                     }],
-                    fold: false,
-                }],
-            };
-            let renderer = Renderer::styled();
-            writeln!(config.shell().err(), "{}", renderer.render(snippet))?;
-            return Err(AlreadyPrintedError::new(e.into()).into());
-        }
-    };
+                };
+                let renderer = Renderer::styled();
+                writeln!(config.shell().err(), "{}", renderer.render(snippet))?;
+                return Err(AlreadyPrintedError::new(e.into()).into());
+            }
+        };
     let add_unused = |warnings: &mut Warnings| {
         for key in unused {
             warnings.add_warning(format!("unused manifest key: {}", key));
@@ -183,10 +184,33 @@ fn read_manifest_from_str(
             }
         }
     }
+
+    let mut public_deps_without_z = BTreeSet::new();
+    if let Some(deps) = &mut manifest.dependencies {
+        for (name, dep) in deps {
+            if let InheritableDependency::Value(toml_dep) = dep {
+                if toml_dep.is_public() && !config.cli_unstable().public_dependency {
+                    if let TomlDependency::Detailed(d) = toml_dep {
+                        d.public = Some(false)
+                    }
+                    public_deps_without_z.insert(name.clone());
+                }
+            }
+        }
+    }
+    let public_warn = |warnings: &mut Warnings| {
+        for name in public_deps_without_z {
+            warnings.add_warning(format!(
+                "{name} is public, pass `-Zpublic-dependency` to enable support for it",
+            ))
+        }
+    };
+
     return if manifest.project.is_some() || manifest.package.is_some() {
         let (mut manifest, paths) =
             to_real_manifest(manifest, embedded, source_id, package_root, config)?;
         add_unused(manifest.warnings_mut());
+        public_warn(manifest.warnings_mut());
         if manifest.targets().iter().all(|t| t.is_custom_build()) {
             bail!(
                 "no targets specified in the manifest\n\
@@ -198,6 +222,7 @@ fn read_manifest_from_str(
     } else {
         let (mut m, paths) = to_virtual_manifest(manifest, source_id, package_root, config)?;
         add_unused(m.warnings_mut());
+        public_warn(m.warnings_mut());
         Ok((EitherManifest::Virtual(m), paths))
     };
 
@@ -678,7 +703,6 @@ pub fn to_real_manifest(
         nested_paths: &mut nested_paths,
         config,
         warnings: &mut warnings,
-        features: &features,
         platform: None,
         root: package_root,
     };
@@ -1153,7 +1177,6 @@ fn to_virtual_manifest(
             config,
             warnings: &mut warnings,
             platform: None,
-            features: &features,
             root,
         };
         (replace(&me, &mut cx)?, patch(&me, &mut cx)?)
@@ -1302,7 +1325,6 @@ struct Context<'a, 'b> {
     warnings: &'a mut Vec<String>,
     platform: Option<Platform>,
     root: &'a Path,
-    features: &'a Features,
 }
 
 fn verify_lints(lints: Option<manifest::TomlLints>) -> CargoResult<Option<manifest::TomlLints>> {
@@ -1709,7 +1731,6 @@ pub(crate) fn to_dependency<P: ResolveToPath + Clone>(
     warnings: &mut Vec<String>,
     platform: Option<Platform>,
     root: &Path,
-    features: &Features,
     kind: Option<DepKind>,
 ) -> CargoResult<Dependency> {
     dep_to_dependency(
@@ -1723,7 +1744,6 @@ pub(crate) fn to_dependency<P: ResolveToPath + Clone>(
             warnings,
             platform,
             root,
-            features,
         },
         kind,
     )
@@ -1944,8 +1964,6 @@ fn detailed_dep_to_dependency<P: ResolveToPath + Clone>(
     }
 
     if let Some(p) = orig.public {
-        cx.features.require(Feature::public_dependency())?;
-
         if dep.kind() != DepKind::Normal {
             bail!("'public' specifier can only be used on regular dependencies, not {:?} dependencies", dep.kind());
         }

src/doc/src/reference/unstable.md

@@ -296,11 +296,9 @@ The 'public-dependency' feature allows marking dependencies as 'public'
 or 'private'. When this feature is enabled, additional information is passed to rustc to allow
 the 'exported_private_dependencies' lint to function properly.
 
-This requires the appropriate key to be set in `cargo-features`:
+Pass `-Zpublic-dependency` to cargo to enable support for it.
 
 ```toml
-cargo-features = ["public-dependency"]
-
 [dependencies]
 my_dep = { version = "1.2.3", public = true }
 private_dep = "2.0.0" # Will be 'private' by default

tests/testsuite/artifact_dep.rs

@@ -2573,6 +2573,10 @@ fn with_assumed_host_target_and_optional_build_dep() {
         .run();
 }
 
+// Since public-dependency had switched to non-blocking feature gate,  (See https://github.com/rust-lang/cargo/issues/13308)
+// this test case will warn "trait `c::Trait` from private dependency 'c' in public interface".
+// The weird sutuation is that the warning "warning: `a` (lib) generated 1 warning (1 duplicate)" will appear randomly.
+// Add #[allow(exported_private_dependencies)] to suppress it.
 #[cargo_test]
 fn decouple_same_target_transitive_dep_from_artifact_dep() {
     // See https://github.com/rust-lang/cargo/issues/11463
@@ -2636,7 +2640,7 @@ fn decouple_same_target_transitive_dep_from_artifact_dep() {
             "a/src/lib.rs",
             r#"
                 use b::Trait as _;
-
+                #[allow(exported_private_dependencies)] 
                 pub fn use_b_trait(x: &impl c::Trait) {
                     x.b();
                 }

tests/testsuite/build.rs

@@ -1439,7 +1439,8 @@ fn cargo_default_env_metadata_env_var() {
         -C extra-filename=[..] \
         --out-dir [..] \
         -L dependency=[CWD]/target/debug/deps \
-        --extern bar=[CWD]/target/debug/deps/{prefix}bar{suffix}`
+        --extern 'priv:bar=[CWD]/target/debug/deps/{prefix}bar{suffix}' \
+        -Z unstable-options`
 [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]",
             prefix = env::consts::DLL_PREFIX,
             suffix = env::consts::DLL_SUFFIX,
@@ -1467,7 +1468,8 @@ fn cargo_default_env_metadata_env_var() {
         -C extra-filename=[..] \
         --out-dir [..] \
         -L dependency=[CWD]/target/debug/deps \
-        --extern bar=[CWD]/target/debug/deps/{prefix}bar-[..]{suffix}`
+        --extern 'priv:bar=[CWD]/target/debug/deps/{prefix}bar-[..]{suffix}' \
+        -Z unstable-options`
 [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
 ",
             prefix = env::consts::DLL_PREFIX,
@@ -2445,8 +2447,9 @@ fn verbose_release_build_deps() {
         -C metadata=[..] \
         --out-dir [..] \
         -L dependency=[CWD]/target/release/deps \
-        --extern foo=[CWD]/target/release/deps/{prefix}foo{suffix} \
-        --extern foo=[CWD]/target/release/deps/libfoo.rlib`
+        --extern 'priv:foo=[CWD]/target/release/deps/{prefix}foo{suffix}' \
+        --extern 'priv:foo=[CWD]/target/release/deps/libfoo.rlib' \
+        -Z unstable-options`
 [FINISHED] release [optimized] target(s) in [..]
 ",
             prefix = env::consts::DLL_PREFIX,

tests/testsuite/build_script.rs

@@ -3018,7 +3018,7 @@ fn diamond_passes_args_only_once() {
 [COMPILING] a v0.5.0 ([..]
 [RUNNING] `rustc [..]`
 [COMPILING] foo v0.5.0 ([..]
-[RUNNING] `[..]rmeta -L native=test`
+[RUNNING] `[..] --extern 'priv:a=[..]rmeta' --extern 'priv:b=[..]rmeta' -Z unstable-options -L native=test`
 [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
 ",
         )

tests/testsuite/cargo/z_help/stdout.log

@@ -25,6 +25,7 @@ Available unstable (nightly-only) flags:
     -Z panic-abort-tests        Enable support to run tests with -Cpanic=abort
     -Z precise-pre-release      Enable pre-release versions to be selected with `update --precise`
     -Z profile-rustflags        Enable the `rustflags` option in profiles in .cargo/config.toml file
+    -Z public-dependency        Enable public-dependency to allow marking dependencies as public/private
     -Z publish-timeout          Enable the `publish.timeout` key in .cargo/config.toml file
     -Z rustdoc-map              Allow passing external documentation mappings to rustdoc
     -Z rustdoc-scrape-examples  Allows Rustdoc to scrape code examples from reverse-dependencies

tests/testsuite/cargo_add/detect_workspace_inherit_public/in/primary/Cargo.toml

@@ -1,4 +1,3 @@
-cargo-features = ["public-dependency"]
 [package]
 name = "bar"
 version = "0.0.0"