feat(add): suggest similarly named features

Author: Jujumba

src/cargo/ops/cargo_add/mod.rs

@@ -29,6 +29,7 @@ use crate::core::Summary;
 use crate::core::Workspace;
 use crate::sources::source::QueryKind;
 use crate::util::cache_lock::CacheLockMode;
+use crate::util::edit_distance;
 use crate::util::style;
 use crate::util::toml::lookup_path_base;
 use crate::util::toml_mut::dependency::Dependency;
@@ -168,6 +169,33 @@ pub fn add(workspace: &Workspace<'_>, options: &AddOptions<'_>) -> CargoResult<(
                 write!(message, "no features available for crate {}", dep.name)?;
             } else {
                 if !deactivated.is_empty() {
+                    let mut suggested_features = Vec::new();
+                    for unknown_feature in &unknown_features {
+                        if let Some(suggested_feature) =
+                            edit_distance::closest(unknown_feature, deactivated.iter(), |dep| *dep)
+                        {
+                            suggested_features.push(suggested_feature);
+                        }
+                    }
+                    if (1..=MAX_FEATURE_PRINTS).contains(&suggested_features.len()) {
+                        writeln!(
+                            message,
+                            "help: similarly named feature{suffix1} exist{suffix2}:{newline} {suggestions}",
+                            suffix1 = if suggested_features.len() == 1 { "" } else { "s" },
+                            suffix2 = if suggested_features.len() == 1 { "s" } else { "" },
+                            newline = if suggested_features.len() == 1 { "" } else { "\n" },
+                            suggestions = suggested_features
+                                .into_iter()
+                                .map(|s| s.to_string())
+                                .coalesce(|x, y| if x.len() + y.len() < 78 {
+                                    Ok(format!("{x}, {y}"))
+                                } else {
+                                    Err((x, y))
+                                })
+                                .into_iter()
+                                .format("\n    ")
+                        )?;
+                    }
                     if deactivated.len() <= MAX_FEATURE_PRINTS {
                         writeln!(
                             message,

tests/testsuite/cargo_add/feature_suggestion_multiple/in/Cargo.toml

@@ -0,0 +1,7 @@
+[workspace]
+
+[package]
+name = "cargo-list-test-fixture"
+version = "0.0.0"
+edition = "2024"
+

tests/testsuite/cargo_add/feature_suggestion_multiple/in/src/lib.rs

@@ -0,0 +1,24 @@
+use cargo_test_support::current_dir;
+use cargo_test_support::file;
+use cargo_test_support::prelude::*;
+use cargo_test_support::Project;
+
+#[cargo_test]
+fn case() {
+    let project = Project::from_template(current_dir!().join("in"));
+    let project_root = project.root();
+    let cwd = &project_root;
+
+    cargo_test_support::registry::Package::new("my-package", "0.1.0+my-package")
+        .feature("bar", &[])
+        .feature("foo", &[])
+        .publish();
+
+    snapbox::cmd::Command::cargo_ui()
+        .arg("add")
+        .arg_line("my-package --features baz --features feo")
+        .current_dir(cwd)
+        .assert()
+        .failure()
+        .stderr_eq(file!["stderr.term.svg"]);
+}

tests/testsuite/cargo_add/feature_suggestion_multiple/mod.rs

@@ -0,0 +1,7 @@
+[workspace]
+
+[package]
+name = "cargo-list-test-fixture"
+version = "0.0.0"
+edition = "2024"
+

tests/testsuite/cargo_add/feature_suggestion_multiple/stderr.term.svg

@@ -0,0 +1,24 @@
+use cargo_test_support::current_dir;
+use cargo_test_support::file;
+use cargo_test_support::prelude::*;
+use cargo_test_support::Project;
+
+#[cargo_test]
+fn case() {
+    let project = Project::from_template(current_dir!().join("in"));
+    let project_root = project.root();
+    let cwd = &project_root;
+
+    cargo_test_support::registry::Package::new("my-package", "0.1.0+my-package")
+        .feature("bar", &[])
+        .feature("foo", &[])
+        .publish();
+
+    snapbox::cmd::Command::cargo_ui()
+        .arg("add")
+        .arg_line("my-package --features none_existent")
+        .current_dir(cwd)
+        .assert()
+        .failure()
+        .stderr_eq(file!["stderr.term.svg"]);
+}

tests/testsuite/cargo_add/feature_suggestion_none/in/Cargo.lock

@@ -0,0 +1,7 @@
+[workspace]
+
+[package]
+name = "cargo-list-test-fixture"
+version = "0.0.0"
+edition = "2024"
+

tests/testsuite/cargo_add/feature_suggestion_none/in/Cargo.toml

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

tests/testsuite/cargo_add/feature_suggestion_none/in/src/lib.rs

@@ -0,0 +1,23 @@
+use cargo_test_support::current_dir;
+use cargo_test_support::file;
+use cargo_test_support::prelude::*;
+use cargo_test_support::Project;
+
+#[cargo_test]
+fn case() {
+    let project = Project::from_template(current_dir!().join("in"));
+    let project_root = project.root();
+    let cwd = &project_root;
+
+    cargo_test_support::registry::Package::new("my-package", "0.1.0+my-package")
+        .feature("bar", &[])
+        .publish();
+
+    snapbox::cmd::Command::cargo_ui()
+        .arg("add")
+        .arg_line("my-package --features baz")
+        .current_dir(cwd)
+        .assert()
+        .failure()
+        .stderr_eq(file!["stderr.term.svg"]);
+}

tests/testsuite/cargo_add/feature_suggestion_none/mod.rs

@@ -21,6 +21,9 @@ mod dev_existing_path_base;
 mod dev_prefer_existing_version;
 mod dry_run;
 mod empty_dep_name;
+mod feature_suggestion_multiple;
+mod feature_suggestion_none;
+mod feature_suggestion_single;
 mod features;
 mod features_activated_over_limit;
 mod features_deactivated_over_limit;