Convert valid feature name warning to an error.

src/cargo/core/resolver/version_prefs.rs

@@ -81,7 +81,6 @@ impl VersionPreferences {
 mod test {
     use super::*;
     use crate::core::SourceId;
-    use crate::util::Config;
     use std::collections::BTreeMap;
 
     fn pkgid(name: &str, version: &str) -> PackageId {
@@ -98,10 +97,8 @@ mod test {
 
     fn summ(name: &str, version: &str) -> Summary {
         let pkg_id = pkgid(name, version);
-        let config = Config::default().unwrap();
         let features = BTreeMap::new();
         Summary::new(
-            &config,
             pkg_id,
             Vec::new(),
             &features,

src/cargo/core/summary.rs

@@ -1,6 +1,6 @@
 use crate::core::{Dependency, PackageId, SourceId};
 use crate::util::interning::InternedString;
-use crate::util::{CargoResult, Config};
+use crate::util::CargoResult;
 use anyhow::bail;
 use semver::Version;
 use std::collections::{BTreeMap, HashMap, HashSet};
@@ -30,7 +30,6 @@ struct Inner {
 
 impl Summary {
     pub fn new(
-        config: &Config,
         pkg_id: PackageId,
         dependencies: Vec<Dependency>,
         features: &BTreeMap<InternedString, Vec<InternedString>>,
@@ -49,7 +48,7 @@ impl Summary {
                 )
             }
         }
-        let feature_map = build_feature_map(config, pkg_id, features, &dependencies)?;
+        let feature_map = build_feature_map(pkg_id, features, &dependencies)?;
         Ok(Summary {
             inner: Rc::new(Inner {
                 package_id: pkg_id,
@@ -140,7 +139,6 @@ impl Hash for Summary {
 /// Checks features for errors, bailing out a CargoResult:Err if invalid,
 /// and creates FeatureValues for each feature.
 fn build_feature_map(
-    config: &Config,
     pkg_id: PackageId,
     features: &BTreeMap<InternedString, Vec<InternedString>>,
     dependencies: &[Dependency],
@@ -204,7 +202,7 @@ fn build_feature_map(
                 feature
             );
         }
-        validate_feature_name(config, pkg_id, feature)?;
+        validate_feature_name(pkg_id, feature)?;
         for fv in fvs {
             // Find data for the referenced dependency...
             let dep_data = {
@@ -431,33 +429,63 @@ impl fmt::Display for FeatureValue {
 
 pub type FeatureMap = BTreeMap<InternedString, Vec<FeatureValue>>;
 
-fn validate_feature_name(config: &Config, pkg_id: PackageId, name: &str) -> CargoResult<()> {
+fn validate_feature_name(pkg_id: PackageId, name: &str) -> CargoResult<()> {
     let mut chars = name.chars();
-    const FUTURE: &str = "This was previously accepted but is being phased out; \
-        it will become a hard error in a future release.\n\
-        For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, \
-        and please leave a comment if this will be a problem for your project.";
     if let Some(ch) = chars.next() {
         if !(unicode_xid::UnicodeXID::is_xid_start(ch) || ch == '_' || ch.is_digit(10)) {
-            config.shell().warn(&format!(
+            bail!(
                 "invalid character `{}` in feature `{}` in package {}, \
                 the first character must be a Unicode XID start character or digit \
-                (most letters or `_` or `0` to `9`)\n\
-                {}",
-                ch, name, pkg_id, FUTURE
-            ))?;
+                (most letters or `_` or `0` to `9`)",
+                ch,
+                name,
+                pkg_id
+            );
         }
     }
     for ch in chars {
         if !(unicode_xid::UnicodeXID::is_xid_continue(ch) || ch == '-' || ch == '+' || ch == '.') {
-            config.shell().warn(&format!(
+            bail!(
                 "invalid character `{}` in feature `{}` in package {}, \
                 characters must be Unicode XID characters, `+`, or `.` \
-                (numbers, `+`, `-`, `_`, `.`, or most letters)\n\
-                {}",
-                ch, name, pkg_id, FUTURE
-            ))?;
+                (numbers, `+`, `-`, `_`, `.`, or most letters)",
+                ch,
+                name,
+                pkg_id
+            );
         }
     }
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::sources::CRATES_IO_INDEX;
+    use crate::util::into_url::IntoUrl;
+
+    use crate::core::SourceId;
+
+    #[test]
+    fn valid_feature_names() {
+        let loc = CRATES_IO_INDEX.into_url().unwrap();
+        let source_id = SourceId::for_registry(&loc).unwrap();
+        let pkg_id = PackageId::new("foo", "1.0.0", source_id).unwrap();
+
+        assert!(validate_feature_name(pkg_id, "c++17").is_ok());
+        assert!(validate_feature_name(pkg_id, "128bit").is_ok());
+        assert!(validate_feature_name(pkg_id, "_foo").is_ok());
+        assert!(validate_feature_name(pkg_id, "feat-name").is_ok());
+        assert!(validate_feature_name(pkg_id, "feat_name").is_ok());
+        assert!(validate_feature_name(pkg_id, "foo.bar").is_ok());
+
+        assert!(validate_feature_name(pkg_id, "+foo").is_err());
+        assert!(validate_feature_name(pkg_id, "-foo").is_err());
+        assert!(validate_feature_name(pkg_id, ".foo").is_err());
+        assert!(validate_feature_name(pkg_id, "foo:bar").is_err());
+        assert!(validate_feature_name(pkg_id, "foo?").is_err());
+        assert!(validate_feature_name(pkg_id, "?foo").is_err());
+        assert!(validate_feature_name(pkg_id, "ⒶⒷⒸ").is_err());
+        assert!(validate_feature_name(pkg_id, "a¼").is_err());
+    }
+}

src/cargo/sources/registry/index.rs

@@ -408,7 +408,6 @@ impl<'cfg> RegistryIndex<'cfg> {
         'a: 'b,
     {
         let source_id = self.source_id;
-        let config = self.config;
 
         // First up parse what summaries we have available.
         let name = InternedString::new(name);
@@ -425,15 +424,13 @@ impl<'cfg> RegistryIndex<'cfg> {
             .versions
             .iter_mut()
             .filter_map(move |(k, v)| if req.matches(k) { Some(v) } else { None })
-            .filter_map(
-                move |maybe| match maybe.parse(config, raw_data, source_id) {
-                    Ok(summary) => Some(summary),
-                    Err(e) => {
-                        info!("failed to parse `{}` registry package: {}", name, e);
-                        None
-                    }
-                },
-            )
+            .filter_map(move |maybe| match maybe.parse(raw_data, source_id) {
+                Ok(summary) => Some(summary),
+                Err(e) => {
+                    info!("failed to parse `{}` registry package: {}", name, e);
+                    None
+                }
+            })
             .filter(move |is| {
                 if is.v > INDEX_V_MAX {
                     debug!(
@@ -714,7 +711,7 @@ impl Summaries {
                     // allow future cargo implementations to break the
                     // interpretation of each line here and older cargo will simply
                     // ignore the new lines.
-                    let summary = match IndexSummary::parse(config, line, source_id) {
+                    let summary = match IndexSummary::parse(line, source_id) {
                         Ok(summary) => summary,
                         Err(e) => {
                             // This should only happen when there is an index
@@ -863,17 +860,12 @@ impl MaybeIndexSummary {
     /// Does nothing if this is already `Parsed`, and otherwise the `raw_data`
     /// passed in is sliced with the bounds in `Unparsed` and then actually
     /// parsed.
-    fn parse(
-        &mut self,
-        config: &Config,
-        raw_data: &[u8],
-        source_id: SourceId,
-    ) -> CargoResult<&IndexSummary> {
+    fn parse(&mut self, raw_data: &[u8], source_id: SourceId) -> CargoResult<&IndexSummary> {
         let (start, end) = match self {
             MaybeIndexSummary::Unparsed { start, end } => (*start, *end),
             MaybeIndexSummary::Parsed(summary) => return Ok(summary),
         };
-        let summary = IndexSummary::parse(config, &raw_data[start..end], source_id)?;
+        let summary = IndexSummary::parse(&raw_data[start..end], source_id)?;
         *self = MaybeIndexSummary::Parsed(summary);
         match self {
             MaybeIndexSummary::Unparsed { .. } => unreachable!(),
@@ -894,7 +886,7 @@ impl IndexSummary {
     ///
     /// The `line` provided is expected to be valid JSON. It is supposed to be
     /// a [`IndexPackage`].
-    fn parse(config: &Config, line: &[u8], source_id: SourceId) -> CargoResult<IndexSummary> {
+    fn parse(line: &[u8], source_id: SourceId) -> CargoResult<IndexSummary> {
         // ****CAUTION**** Please be extremely careful with returning errors
         // from this function. Entries that error are not included in the
         // index cache, and can cause cargo to get confused when switching
@@ -925,7 +917,7 @@ impl IndexSummary {
                 features.entry(name).or_default().extend(values);
             }
         }
-        let mut summary = Summary::new(config, pkgid, deps, &features, links, rust_version)?;
+        let mut summary = Summary::new(pkgid, deps, &features, links, rust_version)?;
         summary.set_checksum(cksum);
         Ok(IndexSummary {
             summary,

src/cargo/util/toml/mod.rs

@@ -2432,7 +2432,6 @@ impl TomlManifest {
         let empty_features = BTreeMap::new();
 
         let summary = Summary::new(
-            config,
             pkgid,
             deps,
             me.features.as_ref().unwrap_or(&empty_features),

tests/testsuite/features.rs

@@ -1937,8 +1937,8 @@ fn nonexistent_required_features() {
 }
 
 #[cargo_test]
-fn invalid_feature_names_warning() {
-    // Warnings for more restricted feature syntax.
+fn invalid_feature_names_error() {
+    // Errors for more restricted feature syntax.
     let p = project()
         .file(
             "Cargo.toml",
@@ -1948,72 +1948,57 @@ fn invalid_feature_names_warning() {
                 version = "0.1.0"
 
                 [features]
-                # Some valid, but unusual names, shouldn't warn.
-                "c++17" = []
-                "128bit" = []
-                "_foo" = []
-                "feat-name" = []
-                "feat_name" = []
-                "foo.bar" = []
-
-                # Invalid names.
+                # Invalid start character.
                 "+foo" = []
-                "-foo" = []
-                ".foo" = []
-                "foo:bar" = []
-                "foo?" = []
-                "?foo" = []
-                "ⒶⒷⒸ" = []
-                "a¼" = []
             "#,
         )
         .file("src/lib.rs", "")
         .build();
 
-    // Unfortunately the warnings are duplicated due to the Summary being
-    // loaded twice (once in the Workspace, and once in PackageRegistry) and
-    // Cargo does not have a de-duplication system. This should probably be
-    // OK, since I'm not expecting this to affect anyone.
     p.cargo("check")
-        .with_stderr("\
-[WARNING] invalid character `+` in feature `+foo` in package foo v0.1.0 ([ROOT]/foo), the first character must be a Unicode XID start character or digit (most letters or `_` or `0` to `9`)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[WARNING] invalid character `-` in feature `-foo` in package foo v0.1.0 ([ROOT]/foo), the first character must be a Unicode XID start character or digit (most letters or `_` or `0` to `9`)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[WARNING] invalid character `.` in feature `.foo` in package foo v0.1.0 ([ROOT]/foo), the first character must be a Unicode XID start character or digit (most letters or `_` or `0` to `9`)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[WARNING] invalid character `?` in feature `?foo` in package foo v0.1.0 ([ROOT]/foo), the first character must be a Unicode XID start character or digit (most letters or `_` or `0` to `9`)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[WARNING] invalid character `¼` in feature `a¼` in package foo v0.1.0 ([ROOT]/foo), characters must be Unicode XID characters, `+`, or `.` (numbers, `+`, `-`, `_`, `.`, or most letters)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[WARNING] invalid character `:` in feature `foo:bar` in package foo v0.1.0 ([ROOT]/foo), characters must be Unicode XID characters, `+`, or `.` (numbers, `+`, `-`, `_`, `.`, or most letters)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[WARNING] invalid character `?` in feature `foo?` in package foo v0.1.0 ([ROOT]/foo), characters must be Unicode XID characters, `+`, or `.` (numbers, `+`, `-`, `_`, `.`, or most letters)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[WARNING] invalid character `Ⓐ` in feature `ⒶⒷⒸ` in package foo v0.1.0 ([ROOT]/foo), the first character must be a Unicode XID start character or digit (most letters or `_` or `0` to `9`)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[WARNING] invalid character `Ⓑ` in feature `ⒶⒷⒸ` in package foo v0.1.0 ([ROOT]/foo), characters must be Unicode XID characters, `+`, or `.` (numbers, `+`, `-`, `_`, `.`, or most letters)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[WARNING] invalid character `Ⓒ` in feature `ⒶⒷⒸ` in package foo v0.1.0 ([ROOT]/foo), characters must be Unicode XID characters, `+`, or `.` (numbers, `+`, `-`, `_`, `.`, or most letters)
-This was previously accepted but is being phased out; it will become a hard error in a future release.
-For more information, see issue #8813 <https://github.com/rust-lang/cargo/issues/8813>, and please leave a comment if this will be a problem for your project.
-[CHECKING] foo v0.1.0 [..]
-[FINISHED] [..]
-")
+        .with_status(101)
+        .with_stderr(
+            "\
+error: failed to parse manifest at `[ROOT]/foo/Cargo.toml`
+
+Caused by:
+  invalid character `+` in feature `+foo` in package foo v0.1.0 ([ROOT]/foo), \
+  the first character must be a Unicode XID start character or digit \
+  (most letters or `_` or `0` to `9`)
+",
+        )
+        .run();
+
+    p.change_file(
+        "Cargo.toml",
+        r#"
+            [package]
+            name = "foo"
+            version = "0.1.0"
+
+            [features]
+            # Invalid continue character.
+            "a&b" = []
+        "#,
+    );
+
+    p.cargo("check")
+        .with_status(101)
+        .with_stderr(
+            "\
+error: failed to parse manifest at `[ROOT]/foo/Cargo.toml`
+
+Caused by:
+  invalid character `&` in feature `a&b` in package foo v0.1.0 ([ROOT]/foo), \
+  characters must be Unicode XID characters, `+`, or `.` \
+  (numbers, `+`, `-`, `_`, `.`, or most letters)
+",
+        )
         .run();
 }
 
 #[cargo_test]
-fn invalid_feature_names_error() {
+fn invalid_feature_name_slash_error() {
     // Errors for more restricted feature syntax.
     let p = project()
         .file(