fix(fix): Dont remove features when making implicit features explicit

Author: epage

src/cargo/ops/fix.rs

@@ -456,18 +456,19 @@ fn add_feature_for_unused_deps(pkg: &Package, parent: &mut dyn toml_edit::TableL
     for dep in manifest.dependencies() {
         let dep_name_in_toml = dep.name_in_toml();
         if dep.is_optional() && !activated_opt_deps.contains(dep_name_in_toml.as_str()) {
-            fixes += 1;
             if let Some(features) = parent
                 .entry("features")
                 .or_insert(toml_edit::table())
                 .as_table_like_mut()
             {
-                features.insert(
-                    dep_name_in_toml.as_str(),
-                    toml_edit::Item::Value(toml_edit::Value::Array(toml_edit::Array::from_iter(
-                        &[format!("dep:{}", dep_name_in_toml)],
-                    ))),
-                );
+                features
+                    .entry(dep_name_in_toml.as_str())
+                    .or_insert_with(|| {
+                        fixes += 1;
+                        toml_edit::Item::Value(toml_edit::Value::Array(
+                            toml_edit::Array::from_iter(&[format!("dep:{}", dep_name_in_toml)]),
+                        ))
+                    });
             }
         }
     }

tests/testsuite/fix.rs

@@ -2705,7 +2705,7 @@ unrelated-dep-feature = ["unrelated-feature/a", "unrelated-feature/b"]
         .with_stderr(
             "\
 [MIGRATING] Cargo.toml from 2021 edition to 2024
-[FIXED] Cargo.toml (3 fixes)
+[FIXED] Cargo.toml (1 fix)
 [UPDATING] `dummy-registry` index
 [LOCKING] 5 packages to latest compatible versions
 [CHECKING] foo v0.1.0 ([CWD])
@@ -2730,10 +2730,10 @@ renamed-feature = { version = "0.1.0", optional = true }
 unrelated-feature = { version = "0.1.0", optional = true }
 
 [features]
-dep-feature = ["dep:dep-feature"]
+dep-feature = ["dep-feature/a", "dep-feature/b"]
 dep-and-dep-feature = ["dep:dep-and-dep-feature", "dep-and-dep-feature/a", "dep-and-dep-feature/b"]
 renamed = ["renamed-feature/a", "renamed-feature/b"]
-unrelated-feature = ["dep:unrelated-feature"]
+unrelated-feature = []
 unrelated-dep-feature = ["unrelated-feature/a", "unrelated-feature/b"]
 renamed-feature = ["dep:renamed-feature"]