fix: preserve independent mod toggles

docs/MOD_PACKAGES.md

@@ -135,10 +135,18 @@ derived-disc recipe is rejected after option resolution; packages should use a
 single owner package for structural transforms and dependencies/conflicts for
 external ownership.
 
+Do not split one structural option system into many mutually exclusive
+full-disc packages. For example, a game-wide Tweaks system should be one package
+with launcher options and a conditional recipe matrix. Choices that are
+mutually exclusive by design belong inside that package as option values, while
+unrelated mods should remain separate packages and compose normally.
+
 ## Resolution rules
 
 - Installed versions are side-by-side. The launcher can select an older version
   to roll back.
+- Enabling or disabling one package changes only that package. It does not
+  silently toggle other packages.
 - Enabled packages are topologically ordered by dependencies, then by stable
   package/patch order.
 - Missing dependencies, version mismatches, declared conflicts, dependency

runtime/src/mod_packages.cpp

@@ -1088,26 +1088,6 @@ bool ModPackageManager::set_enabled(const std::string& id, bool enabled, std::st
         return false;
     }
     selections_[id].enabled = enabled;
-    if (!enabled) return true;
-
-    const ModPackage* package = find_selected(packages_, id, selections_[id]);
-    if (!package) return true;
-
-    auto conflicts_with_enabled = [&](const std::string& other_id,
-                                      const ModPackage& other) {
-        const auto declared = std::find(package->conflicts.begin(),
-                                        package->conflicts.end(), other_id);
-        if (declared != package->conflicts.end()) return true;
-        const auto reverse = std::find(other.conflicts.begin(), other.conflicts.end(), id);
-        return reverse != other.conflicts.end();
-    };
-
-    for (auto& [other_id, selection] : selections_) {
-        if (other_id == id || !selection.enabled) continue;
-        const ModPackage* other = find_selected(packages_, other_id, selection);
-        if (other && conflicts_with_enabled(other_id, *other))
-            selection.enabled = false;
-    }
     return true;
 }
 

runtime/tests/test_mod_packages.cpp

@@ -191,9 +191,11 @@ int main() {
     check(reload.scan(&error), error.c_str());
     check(reload.set_enabled("conflict.a", true, &error), error.c_str());
     check(reload.set_enabled("conflict.b", true, &error), error.c_str());
-    check(!reload.selections().at("conflict.a").enabled &&
+    check(reload.selections().at("conflict.a").enabled &&
               reload.selections().at("conflict.b").enabled,
-          "enabling a conflicting package must disable the previous package");
+          "enabling a package must not silently disable another package");
+    check(!reload.resolve("SLUS-TEST").ok,
+          "declared conflicts must fail resolution");
 
     write_text(root / "packages/matrix.mod/1.0.0/manifest.toml",
                manifest("matrix.mod", "1.0.0",
@@ -228,6 +230,7 @@ int main() {
                    "when = { title = \"rockman\", script = \"retranslation\" }\n"));
     write_text(root / "packages/matrix.mod/1.0.0/assets/matrix.xdelta3", "test");
     check(reload.scan(&error), error.c_str());
+    check(reload.set_enabled("conflict.a", false, &error), error.c_str());
     check(reload.set_enabled("conflict.b", false, &error), error.c_str());
     check(reload.set_enabled("matrix.mod", true, &error), error.c_str());
     check(reload.set_option("matrix.mod", "title", "rockman", &error), error.c_str());