Add features2 to the index.

Author: ehuss

crates/cargo-test-support/src/registry.rs

@@ -4,7 +4,7 @@ use cargo::sources::CRATES_IO_INDEX;
 use cargo::util::Sha256;
 use flate2::write::GzEncoder;
 use flate2::Compression;
-use std::collections::HashMap;
+use std::collections::BTreeMap;
 use std::fmt::Write as _;
 use std::fs::{self, File};
 use std::io::{BufRead, BufReader, Write};
@@ -319,7 +319,7 @@ pub struct Package {
     deps: Vec<Dependency>,
     files: Vec<PackageFile>,
     yanked: bool,
-    features: HashMap<String, Vec<String>>,
+    features: FeatureMap,
     local: bool,
     alternative: bool,
     invalid_json: bool,
@@ -330,6 +330,8 @@ pub struct Package {
     v: Option<u32>,
 }
 
+type FeatureMap = BTreeMap<String, Vec<String>>;
+
 #[derive(Clone)]
 pub struct Dependency {
     name: String,
@@ -394,7 +396,7 @@ impl Package {
             deps: Vec::new(),
             files: Vec::new(),
             yanked: false,
-            features: HashMap::new(),
+            features: BTreeMap::new(),
             local: false,
             alternative: false,
             invalid_json: false,
@@ -609,15 +611,21 @@ impl Package {
         } else {
             serde_json::json!(self.name)
         };
+        // This emulates what crates.io may do in the future.
+        let (features, features2) = split_index_features(self.features.clone());
         let mut json = serde_json::json!({
             "name": name,
             "vers": self.vers,
             "deps": deps,
             "cksum": cksum,
-            "features": self.features,
+            "features": features,
             "yanked": self.yanked,
             "links": self.links,
         });
+        if let Some(f2) = &features2 {
+            json["features2"] = serde_json::json!(f2);
+            json["v"] = serde_json::json!(2);
+        }
         if let Some(v) = self.v {
             json["v"] = serde_json::json!(v);
         }
@@ -850,3 +858,21 @@ impl Dependency {
         self
     }
 }
+
+fn split_index_features(mut features: FeatureMap) -> (FeatureMap, Option<FeatureMap>) {
+    let mut features2 = FeatureMap::new();
+    for (feat, values) in features.iter_mut() {
+        if values
+            .iter()
+            .any(|value| value.starts_with("dep:") || value.contains("?/"))
+        {
+            let new_values = values.drain(..).collect();
+            features2.insert(feat.clone(), new_values);
+        }
+    }
+    if features2.is_empty() {
+        (features, None)
+    } else {
+        (features, Some(features2))
+    }
+}

src/cargo/sources/registry/index.rs

@@ -308,7 +308,11 @@ impl<'cfg> RegistryIndex<'cfg> {
         // minimize the amount of work being done here and parse as little as
         // necessary.
         let raw_data = &summaries.raw_data;
-        let max_version = 1;
+        let max_version = if namespaced_features || weak_dep_features {
+            2
+        } else {
+            1
+        };
         Ok(summaries
             .versions
             .iter_mut()
@@ -770,7 +774,8 @@ impl IndexSummary {
             vers,
             cksum,
             deps,
-            features,
+            mut features,
+            features2,
             yanked,
             links,
             v,
@@ -782,6 +787,11 @@ impl IndexSummary {
             .into_iter()
             .map(|dep| dep.into_dep(source_id))
             .collect::<CargoResult<Vec<_>>>()?;
+        if let Some(features2) = features2 {
+            for (name, values) in features2 {
+                features.entry(name).or_default().extend(values);
+            }
+        }
         let mut summary = Summary::new(config, pkgid, deps, &features, links)?;
         summary.set_checksum(cksum);
         Ok(IndexSummary {

src/cargo/sources/registry/mod.rs

@@ -258,6 +258,13 @@ pub struct RegistryPackage<'a> {
     #[serde(borrow)]
     deps: Vec<RegistryDependency<'a>>,
     features: BTreeMap<InternedString, Vec<InternedString>>,
+    /// This field contains features with new, extended syntax. Specifically,
+    /// namespaced features (`dep:`) and weak dependencies (`pkg?/feat`).
+    ///
+    /// This is separated from `features` because versions older than 1.19
+    /// will fail to load due to not being able to parse the new syntax, even
+    /// with a `Cargo.lock` file.
+    features2: Option<BTreeMap<InternedString, Vec<InternedString>>>,
     cksum: String,
     /// If `true`, Cargo will skip this version when resolving.
     ///
@@ -274,10 +281,12 @@ pub struct RegistryPackage<'a> {
     /// If this is None, it defaults to version 1. Entries with unknown
     /// versions are ignored.
     ///
+    /// Version `2` format adds the `features2` field.
+    ///
     /// This provides a method to safely introduce changes to index entries
     /// and allow older versions of cargo to ignore newer entries it doesn't
     /// understand. This is honored as of 1.51, so unfortunately older
-    /// versions will ignore it, and potentially misinterpret version 1 and
+    /// versions will ignore it, and potentially misinterpret version 2 and
     /// newer entries.
     ///
     /// The intent is that versions older than 1.51 will work with a

tests/testsuite/features_namespaced.rs

@@ -1106,3 +1106,105 @@ feat = ["opt-dep1"]
         )],
     );
 }
+
+#[cargo_test]
+fn publish() {
+    // Publish behavior with explicit dep: syntax.
+    Package::new("bar", "1.0.0").publish();
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.1.0"
+                description = "foo"
+                license = "MIT"
+                homepage = "https://example.com/"
+
+                [dependencies]
+                bar = { version = "1.0", optional = true }
+
+                [features]
+                feat1 = []
+                feat2 = ["dep:bar"]
+                feat3 = ["feat2"]
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("publish --token sekrit -Z namespaced-features")
+        .masquerade_as_nightly_cargo()
+        .with_stderr(
+            "\
+[UPDATING] [..]
+[PACKAGING] foo v0.1.0 [..]
+[VERIFYING] foo v0.1.0 [..]
+[COMPILING] foo v0.1.0 [..]
+[FINISHED] [..]
+[UPLOADING] foo v0.1.0 [..]
+",
+        )
+        .run();
+
+    publish::validate_upload_with_contents(
+        r#"
+        {
+          "authors": [],
+          "badges": {},
+          "categories": [],
+          "deps": [
+            {
+              "default_features": true,
+              "features": [],
+              "kind": "normal",
+              "name": "bar",
+              "optional": true,
+              "registry": "https://github.com/rust-lang/crates.io-index",
+              "target": null,
+              "version_req": "^1.0"
+            }
+          ],
+          "description": "foo",
+          "documentation": null,
+          "features": {
+            "feat1": [],
+            "feat2": ["dep:bar"],
+            "feat3": ["feat2"]
+          },
+          "homepage": "https://example.com/",
+          "keywords": [],
+          "license": "MIT",
+          "license_file": null,
+          "links": null,
+          "name": "foo",
+          "readme": null,
+          "readme_file": null,
+          "repository": null,
+          "vers": "0.1.0"
+          }
+        "#,
+        "foo-0.1.0.crate",
+        &["Cargo.toml", "Cargo.toml.orig", "src/lib.rs"],
+        &[(
+            "Cargo.toml",
+            r#"[..]
+[package]
+name = "foo"
+version = "0.1.0"
+description = "foo"
+homepage = "https://example.com/"
+license = "MIT"
+[dependencies.bar]
+version = "1.0"
+optional = true
+
+[features]
+feat1 = []
+feat2 = ["dep:bar"]
+feat3 = ["feat2"]
+"#,
+        )],
+    );
+}