Validate at-least-one-of features across selected packages

CHANGELOG.md

@@ -12,6 +12,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Report an error for `--at-least-one-of` features absent from every selected package, unless `--ignore-unknown-features` is used.
+
 ## [0.6.45] - 2026-05-30
 
 - Support versioned name and package spec in `--package` and `--exclude`. ([#298](https://github.com/taiki-e/cargo-hack/pull/298))

README.md

@@ -153,6 +153,9 @@ OPTIONS:
             To specify multiple groups, use this option multiple times: `--at-least-one-of a,b
             --at-least-one-of c,d`
 
+            Features absent from all selected packages cause an error, unless
+            --ignore-unknown-features is used.
+
             This flag can only be used together with --feature-powerset flag.
 
         --include-features <FEATURES>...
@@ -181,7 +184,8 @@ OPTIONS:
         --ignore-unknown-features
             Skip passing --features flag to `cargo` if that feature does not exist in the package.
 
-            This flag can be used with --features, --include-features, or --group-features.
+            This flag can be used with --features, --include-features, --group-features, or
+            --at-least-one-of.
 
         --rust-version
             Perform commands on `package.rust-version`.

src/cli.rs

@@ -431,11 +431,16 @@ impl Args {
         term::set_coloring(color.as_deref())?;
 
         if ignore_unknown_features {
-            if features.is_empty() && include_features.is_empty() && group_features.is_empty() {
+            if features.is_empty()
+                && include_features.is_empty()
+                && group_features.is_empty()
+                && at_least_one_of.is_empty()
+            {
                 requires("--ignore-unknown-features", &[
                     "--features",
                     "--include-features",
                     "--group-features",
+                    "--at-least-one-of",
                 ])?;
             }
             if !include_features.is_empty() {
@@ -838,6 +843,7 @@ const HELP: &[HelpText<'_>] = &[
         &[
             "To specify multiple groups, use this option multiple times: \
              `--at-least-one-of a,b --at-least-one-of c,d`",
+            "Features absent from all selected packages cause an error, unless --ignore-unknown-features is used.",
             "This flag can only be used together with --feature-powerset flag.",
         ],
     ),
@@ -869,7 +875,9 @@ const HELP: &[HelpText<'_>] = &[
         "--ignore-unknown-features",
         "",
         "Skip passing --features flag to `cargo` if that feature does not exist in the package",
-        &["This flag can be used with --features, --include-features, or --group-features."],
+        &[
+            "This flag can be used with --features, --include-features, --group-features, or --at-least-one-of.",
+        ],
     ),
     ("", "--rust-version", "", "Perform commands on `package.rust-version`", &[
         "This cannot be used with --version-range.",

src/features.rs

@@ -234,10 +234,7 @@ pub(crate) fn feature_powerset<'a>(
         .filter(move |fs| {
             // all() returns true if at_least_one_of is empty
             at_least_one_of.iter().all(|required_set| {
-                fs
-                    .iter()
-                    .flat_map(|f| f.as_group())
-                    .any(|f| required_set.contains(f.as_str()))
+                fs.iter().flat_map(|f| f.as_group()).any(|f| required_set.contains(f.as_str()))
             })
         })
         .filter(move |fs| {
@@ -259,7 +256,9 @@ pub(crate) fn feature_powerset<'a>(
         .collect()
 }
 
-fn feature_deps(map: &BTreeMap<Box<str>, Box<[Box<str>]>>) -> BTreeMap<&str, BTreeSet<&str>> {
+pub(crate) fn feature_deps(
+    map: &BTreeMap<Box<str>, Box<[Box<str>]>>,
+) -> BTreeMap<&str, BTreeSet<&str>> {
     fn rec<'a>(
         map: &'a BTreeMap<Box<str>, Box<[Box<str>]>>,
         set: &mut BTreeSet<&'a str>,

src/main.rs

@@ -65,6 +65,22 @@ fn try_main() -> Result<()> {
         }
 
         let packages = determine_package_list(cx)?;
+        if !cx.ignore_unknown_features && !cx.at_least_one_of.is_empty() {
+            let feature_deps: Vec<_> = packages
+                .iter()
+                .map(|pkg| features::feature_deps(&cx.packages(pkg.id).features))
+                .collect();
+            for name in cx.at_least_one_of.iter().flat_map(Feature::as_group) {
+                if !feature_deps.iter().any(|deps| {
+                    deps.contains_key(name.as_str())
+                        || deps.values().any(|features| features.contains(name.as_str()))
+                }) {
+                    bail!(
+                        "feature `{name}` specified by --at-least-one-of not found in any selected package"
+                    );
+                }
+            }
+        }
         let mut progress = Progress::default();
         let mut keep_going = KeepGoing::default();
         if let Some(range) = cx.version_range {

tests/long-help.txt

@@ -123,6 +123,9 @@ OPTIONS:
             To specify multiple groups, use this option multiple times: `--at-least-one-of a,b
             --at-least-one-of c,d`
 
+            Features absent from all selected packages cause an error, unless
+            --ignore-unknown-features is used.
+
             This flag can only be used together with --feature-powerset flag.
 
         --include-features <FEATURES>...
@@ -151,7 +154,8 @@ OPTIONS:
         --ignore-unknown-features
             Skip passing --features flag to `cargo` if that feature does not exist in the package.
 
-            This flag can be used with --features, --include-features, or --group-features.
+            This flag can be used with --features, --include-features, --group-features, or
+            --at-least-one-of.
 
         --rust-version
             Perform commands on `package.rust-version`.

tests/test.rs

@@ -465,7 +465,7 @@ fn ignore_unknown_features_failure() {
         .stderr_contains(
             "
             --ignore-unknown-features can only be used together with --features, --include-features, \
-            or --group-features
+            --group-features, or --at-least-one-of
             ",
         );
 
@@ -937,6 +937,59 @@ fn include_features() {
         );
 }
 
+#[test]
+fn at_least_one_of_unknown_features() {
+    cargo_hack(["check", "--feature-powerset", "--at-least-one-of", "a,missing"])
+        .assert_failure("real")
+        .stderr_contains(
+            "feature `missing` specified by --at-least-one-of not found in any selected package",
+        )
+        .stderr_not_contains("running `cargo");
+
+    // A feature only needs to exist in one of the selected workspace packages.
+    cargo_hack(["check", "--feature-powerset", "--at-least-one-of", "a,f"])
+        .assert_success("virtual");
+
+    cargo_hack(["check", "--feature-powerset", "--at-least-one-of", "a,f", "--exclude", "member2"])
+        .assert_failure("virtual")
+        .stderr_contains(
+            "feature `f` specified by --at-least-one-of not found in any selected package",
+        );
+
+    cargo_hack([
+        "check",
+        "--feature-powerset",
+        "--at-least-one-of",
+        "a,missing",
+        "--ignore-unknown-features",
+    ])
+    .assert_success("real");
+
+    cargo_hack([
+        "check",
+        "--feature-powerset",
+        "--at-least-one-of",
+        "missing,also-missing",
+        "--ignore-unknown-features",
+    ])
+    .assert_success("real");
+
+    cargo_hack(["check", "--feature-powerset", "--at-least-one-of", "a,f", "-p", "member1"])
+        .assert_failure("virtual")
+        .stderr_contains(
+            "feature `f` specified by --at-least-one-of not found in any selected package",
+        );
+
+    // Dependency feature references have always been accepted by the per-package filter.
+    cargo_hack([
+        "check",
+        "--feature-powerset",
+        "--at-least-one-of",
+        "easytime/std,easytime?/default",
+    ])
+    .assert_success2("weak_dep_features_namespaced", Some(60));
+}
+
 #[test]
 fn exclude_features() {
     cargo_hack(["check", "--each-feature", "--exclude-features", "f"])