Fix config profiles using "dev" in cargo test.

src/cargo/core/profiles.rs

@@ -1014,27 +1014,33 @@ fn merge_config_profiles(
         Some(profiles) => profiles.get_all().clone(),
         None => BTreeMap::new(),
     };
-    // List of profile names to check if defined in config only.
-    let mut check_to_add = vec![requested_profile];
+    // Set of profile names to check if defined in config only.
+    let mut check_to_add = HashSet::new();
+    check_to_add.insert(requested_profile);
     // Merge config onto manifest profiles.
     for (name, profile) in &mut profiles {
         if let Some(config_profile) = get_config_profile(name, config, features)? {
             profile.merge(&config_profile);
         }
         if let Some(inherits) = &profile.inherits {
-            check_to_add.push(*inherits);
+            check_to_add.insert(*inherits);
         }
     }
+    // Add the built-in profiles. This is important for things like `cargo
+    // test` which implicitly use the "dev" profile for dependencies.
+    for name in &["dev", "release", "test", "bench"] {
+        check_to_add.insert(InternedString::new(name));
+    }
     // Add config-only profiles.
     // Need to iterate repeatedly to get all the inherits values.
-    let mut current = Vec::new();
+    let mut current = HashSet::new();
     while !check_to_add.is_empty() {
         std::mem::swap(&mut current, &mut check_to_add);
-        for name in current.drain(..) {
+        for name in current.drain() {
             if !profiles.contains_key(&name) {
                 if let Some(config_profile) = get_config_profile(&name, config, features)? {
                     if let Some(inherits) = &config_profile.inherits {
-                        check_to_add.push(*inherits);
+                        check_to_add.insert(*inherits);
                     }
                     profiles.insert(name, config_profile);
                 }

tests/testsuite/profile_config.rs

@@ -1,6 +1,7 @@
 //! Tests for profiles defined in config files.
 
 use cargo_test_support::paths::CargoPathExt;
+use cargo_test_support::registry::Package;
 use cargo_test_support::{basic_lib_manifest, paths, project};
 
 #[cargo_test]
@@ -454,3 +455,38 @@ fn named_env_profile() {
         .with_stderr_contains("[..]-C codegen-units=1 [..]")
         .run();
 }
+
+#[cargo_test]
+fn test_with_dev_profile() {
+    // `cargo test` uses "dev" profile for dependencies.
+    Package::new("somedep", "1.0.0").publish();
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "0.1.0"
+
+            [dependencies]
+            somedep = "1.0"
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+    p.cargo("test --lib --no-run -v")
+        .env("CARGO_PROFILE_DEV_DEBUG", "0")
+        .with_stderr(
+            "\
+[UPDATING] [..]
+[DOWNLOADING] [..]
+[DOWNLOADED] [..]
+[COMPILING] somedep v1.0.0
+[RUNNING] `rustc --crate-name somedep [..]-C debuginfo=0[..]
+[COMPILING] foo v0.1.0 [..]
+[RUNNING] `rustc --crate-name foo [..]-C debuginfo=2[..]
+[FINISHED] [..]
+",
+        )
+        .run();
+}