Remove feature components that activate features of dev-dependencies

For example, syn has a feature `test` that activates the
`all-features` feature of the dev-dependency `syn-test-suite`:

```toml
[features]
test = ["syn-test-suite/all-features"]

[dev-dependencies.syn-test-suite]
version = "0"
```

We don't store the dev-dependencies in the index which causes Cargo to
complain when fetching `syn` because the feature refers to a
dependency that doesn't exist.

Author: shepmaster

Cargo.lock

@@ -29,7 +29,7 @@ lint_groups_priority = { level = "allow", priority = 1 } # Remove after 1.80. ht
 
 [workspace.dependencies]
 argh = { version = "0.1.12", default-features = false }
-registry-conformance = { version = "0.5.0", registry = "registry-conformance" }
+registry-conformance = { version = "0.5.2", registry = "registry-conformance" }
 snafu = { version = "0.8.2", default-features = false, features = ["rust_1_65", "std"] }
 tokio = { version = "1.37.0", default-features = false, features = ["macros", "process", "rt-multi-thread"] }
 

Cargo.toml

@@ -1014,9 +1014,31 @@ enum ExtractRootCargoTomlError {
 fn adapt_cargo_toml_to_index_entry(
     global: &Global,
     config: &ConfigV1,
-    cargo_toml: cargo_toml::Root,
+    mut cargo_toml: cargo_toml::Root,
     checksum_hex: String,
 ) -> index_entry::Root {
+    // Remove features that refer to dev-dependencies as we don't
+    // track those anyway.
+    {
+        // Ignore dependencies that also occur as a regular or build
+        // dependency, as we *do* track those.
+        let mut only_dev_dep_names = cargo_toml.dev_dependencies.keys().collect::<BTreeSet<_>>();
+        for name in cargo_toml.dependencies.keys().chain(cargo_toml.build_dependencies.keys()) {
+            only_dev_dep_names.remove(name);
+        }
+
+        for name in only_dev_dep_names {
+            // We don't care about the official package name here as the
+            // feature syntax has to match the user-specified dependency
+            // name.
+            let prefix = format!("{name}/");
+
+            for enabled in cargo_toml.features.values_mut() {
+                enabled.retain(|enable| !enable.starts_with(&prefix));
+            }
+        }
+    }
+
     let mut deps: Vec<_> = cargo_toml
         .dependencies
         .into_iter()
@@ -1126,6 +1148,9 @@ mod cargo_toml {
         #[serde(default)]
         pub build_dependencies: Dependencies,
 
+        #[serde(default)]
+        pub dev_dependencies: Dependencies,
+
         #[serde(default)]
         pub target: BTreeMap<String, Target>,
     }