From dd3f434d0ddced8e29da4dab397c11f706c5a54a Mon Sep 17 00:00:00 2001
From: hi-rustin <rustin.liu@gmail.com>
Date: Tue, 7 Nov 2023 20:03:10 +0800
Subject: [PATCH 1/2] Do not allow empty feature name

Signed-off-by: hi-rustin <rustin.liu@gmail.com>
---
 src/cargo/core/summary.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/cargo/core/summary.rs b/src/cargo/core/summary.rs
index 128c0db9cb1..0dc55c3cf75 100644
--- a/src/cargo/core/summary.rs
+++ b/src/cargo/core/summary.rs
@@ -431,6 +431,9 @@ impl fmt::Display for FeatureValue {
 pub type FeatureMap = BTreeMap<InternedString, Vec<FeatureValue>>;
 
 fn validate_feature_name(pkg_id: PackageId, name: &str) -> CargoResult<()> {
+    if name.is_empty() {
+        bail!("feature name cannot be empty");
+    }
     let mut chars = name.chars();
     if let Some(ch) = chars.next() {
         if !(unicode_xid::UnicodeXID::is_xid_start(ch) || ch == '_' || ch.is_digit(10)) {
@@ -488,5 +491,6 @@ mod tests {
         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());
+        assert!(validate_feature_name(pkg_id, "").is_err());
     }
 }

From d61816465f25b918acf8800afd8cbbd1c6d73c89 Mon Sep 17 00:00:00 2001
From: hi-rustin <rustin.liu@gmail.com>
Date: Tue, 7 Nov 2023 20:03:35 +0800
Subject: [PATCH 2/2] Add test for empty feature name

Signed-off-by: hi-rustin <rustin.liu@gmail.com>
---
 tests/testsuite/features.rs | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/tests/testsuite/features.rs b/tests/testsuite/features.rs
index 236b6f65181..e44807941d1 100644
--- a/tests/testsuite/features.rs
+++ b/tests/testsuite/features.rs
@@ -35,6 +35,37 @@ Caused by:
         .run();
 }
 
+#[cargo_test]
+fn empty_feature_name() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                authors = []
+
+                [features]
+                "" = []
+            "#,
+        )
+        .file("src/main.rs", "")
+        .build();
+
+    p.cargo("check")
+        .with_status(101)
+        .with_stderr(
+            "\
+[ERROR] failed to parse manifest at `[..]`
+
+Caused by:
+  feature name cannot be empty
+",
+        )
+        .run();
+}
+
 #[cargo_test]
 fn same_name() {
     // Feature with the same name as a dependency.