Add dependency overrides

loader/src/main/java/net/neoforged/fml/loading/FMLConfig.java

@@ -6,6 +6,7 @@
 package net.neoforged.fml.loading;
 
 import com.electronwill.nightconfig.core.CommentedConfig;
+import com.electronwill.nightconfig.core.Config;
 import com.electronwill.nightconfig.core.ConfigSpec;
 import com.electronwill.nightconfig.core.InMemoryFormat;
 import com.electronwill.nightconfig.core.file.CommentedFileConfig;
@@ -19,9 +20,16 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.function.Function;
+import java.util.stream.Collectors;
+import org.jetbrains.annotations.Unmodifiable;
+import org.jetbrains.annotations.UnmodifiableView;
 import org.slf4j.Logger;
 
 public class FMLConfig {
@@ -95,6 +103,7 @@ private static Object maxThreads(final Object value) {
 
     private static final Logger LOGGER = LogUtils.getLogger();
     private static final FMLConfig INSTANCE = new FMLConfig();
+    private static Map<String, List<DependencyOverride>> dependencyOverrides = Map.of();
     private static final ConfigSpec configSpec = new ConfigSpec(
             // Make sure the values are written in the same order as the enum.
             InMemoryFormat.withUniversalSupport().createConfig(LinkedHashMap::new));
@@ -103,6 +112,17 @@ private static Object maxThreads(final Object value) {
         for (ConfigValue cv : ConfigValue.values()) {
             cv.buildConfigEntry(configSpec, configComments);
         }
+
+        // Make sure that we don't end up "correcting" the config and removing dependency overrides
+        // Since we're not writing them by default, the default value can be null and we accept any objects (parsing and validation is done when the config is loaded)
+        configSpec.define("dependencyOverrides", Map::of, object -> true);
+        configComments.set("dependencyOverrides", configComments.createSubConfig());
+        configComments.setComment("dependencyOverrides", """
+                Define dependency overrides below
+                Dependency overrides can be used to forcibly remove a dependency constraint from a mod or to force a mod to load AFTER another mod
+                Using dependency overrides can cause issues. Use at your own risk.
+                Example dependency override for the mod with the id 'targetMod': dependency constraints (incompatibility clauses or restrictive version ranges) against mod 'dep1' are removed, and the mod will now load after the mod 'dep2'
+                dependencyOverrides.targetMod = ["-dep1", "+dep2"]""");
     }
 
     private CommentedConfig configData;
@@ -144,6 +164,43 @@ public static void load() {
             }
         }
         FMLPaths.getOrCreateGameRelativePath(Paths.get(FMLConfig.getConfigValue(ConfigValue.DEFAULT_CONFIG_PATH)));
+
+        // load dependency overrides
+        Map<String, List<DependencyOverride>> dependencyOverrides = new HashMap<>();
+        var overridesObject = INSTANCE.configData.get("dependencyOverrides");
+        if (overridesObject != null) {
+            if (!(overridesObject instanceof Config cfg)) {
+                LOGGER.error("Invalid dependency overrides declaration in config. Expected object but found {}", overridesObject);
+                return;
+            }
+
+            cfg.valueMap().forEach((modId, object) -> {
+                // We accept both dependencyOverrides.target = "-dep" and dependencyOverrides.target = ["-dep"]
+                var asList = object instanceof List<?> ls ? ls : List.of(object);
+                var overrides = dependencyOverrides.computeIfAbsent(modId, k -> new ArrayList<>());
+                for (Object o : asList) {
+                    var str = (String) o;
+                    var start = str.charAt(0);
+                    if (start != '+' && start != '-') {
+                        LOGGER.error("Found invalid dependency override for mod '{}'. Expected +/- in override '{}'. Did you forget to specify the override type?", modId, str);
+                    } else {
+                        var removal = start == '-';
+                        var depMod = str.substring(1);
+                        overrides.add(new DependencyOverride(depMod, removal));
+                    }
+                }
+            });
+        }
+
+        if (!dependencyOverrides.isEmpty()) {
+            LOGGER.warn("*".repeat(30) + " Found dependency overrides " + "*".repeat(30));
+            dependencyOverrides.forEach((modId, ov) -> LOGGER.warn("Dependency overrides for mod '{}': {}", modId, ov.stream().map(DependencyOverride::getMessage).collect(Collectors.joining(", "))));
+            LOGGER.warn("*".repeat(88));
+        }
+
+        // Make the overrides immutable
+        dependencyOverrides.replaceAll((id, list) -> List.copyOf(list));
+        FMLConfig.dependencyOverrides = Collections.unmodifiableMap(dependencyOverrides);
     }
 
     public static String getConfigValue(ConfigValue v) {
@@ -172,4 +229,22 @@ public static <T> void updateConfig(ConfigValue v, T value) {
     public static String defaultConfigPath() {
         return getConfigValue(ConfigValue.DEFAULT_CONFIG_PATH);
     }
+
+    @Unmodifiable
+    public static List<DependencyOverride> getOverrides(String modId) {
+        var ov = dependencyOverrides.get(modId);
+        if (ov == null) return List.of();
+        return ov;
+    }
+
+    @UnmodifiableView
+    public static Map<String, List<DependencyOverride>> getDependencyOverrides() {
+        return Collections.unmodifiableMap(dependencyOverrides);
+    }
+
+    public record DependencyOverride(String modId, boolean remove) {
+        public String getMessage() {
+            return (remove ? "softening dependency constraints against" : "adding explicit AFTER ordering against") + " '" + modId + "'";
+        }
+    }
 }

loader/src/main/java/net/neoforged/fml/loading/ModSorter.java

@@ -75,7 +75,7 @@ public static LoadingModList sort(List<ModFile> plugins, List<ModFile> mods, fin
             // Otherwise, lets try and sort the modlist and proceed
             ModLoadingException modLoadingException = null;
             try {
-                ms.sort();
+                ms.sort(issues);
             } catch (ModLoadingException e) {
                 modLoadingException = e;
             }
@@ -105,7 +105,7 @@ private static <T> List<T> concat(List<T>... lists) {
     }
 
     @SuppressWarnings("UnstableApiUsage")
-    private void sort() {
+    private void sort(List<ModLoadingIssue> issues) {
         // lambdas are identity based, so sorting them is impossible unless you hold reference to them
         final MutableGraph<ModInfo> graph = GraphBuilder.directed().build();
         AtomicInteger counter = new AtomicInteger();
@@ -120,6 +120,26 @@ private void sort() {
                 .map(IModInfo::getDependencies).<IModInfo.ModVersion>mapMulti(Iterable::forEach)
                 .forEach(dep -> addDependency(graph, dep));
 
+        // now consider dependency overrides
+        // we also check their validity here, and report unknown mods as warnings
+        FMLConfig.getDependencyOverrides().forEach((id, overrides) -> {
+            var target = (ModInfo) modIdNameLookup.get(id);
+            if (target == null) {
+                issues.add(ModLoadingIssue.warning("fml.modloadingissue.depoverride.unknown_target", id));
+            } else {
+                for (FMLConfig.DependencyOverride override : overrides) {
+                    var dep = (ModInfo) modIdNameLookup.get(override.modId());
+                    if (dep == null) {
+                        issues.add(ModLoadingIssue.warning("fml.modloadingissue.depoverride.unknown_dependency", override.modId(), id));
+                    } else if (!override.remove()) {
+                        // Add ordering dependency overrides (random order -> target AFTER dependency)
+                        // We do not need to check for overrides that attempt to change the declared order as the sorter will detect the cycle itself and error
+                        graph.putEdge(dep, target);
+                    }
+                }
+            }
+        });
+
         final List<ModInfo> sorted;
         try {
             sorted = TopologicalSort.topologicalSort(graph, Comparator.comparing(infos::get));
@@ -237,7 +257,19 @@ private DependencyResolutionResult verifyDependencyVersions() {
         final var modVersionDependencies = modFiles.stream()
                 .map(ModFile::getModInfos)
                 .<IModInfo>mapMulti(Iterable::forEach)
-                .collect(groupingBy(Function.identity(), flatMapping(e -> e.getDependencies().stream(), toList())));
+                .collect(groupingBy(Function.identity(), flatMapping(e -> {
+                    var overrides = FMLConfig.getOverrides(e.getModId());
+                    // consider overrides and invalidate dependencies that are removed
+                    if (!overrides.isEmpty()) {
+                        var ids = overrides.stream()
+                                .filter(FMLConfig.DependencyOverride::remove)
+                                .map(FMLConfig.DependencyOverride::modId)
+                                .collect(toSet());
+                        return e.getDependencies().stream()
+                                .filter(v -> !ids.contains(v.getModId()));
+                    }
+                    return e.getDependencies().stream();
+                }, toList())));
 
         final var modRequirements = modVersionDependencies.values().stream().<IModInfo.ModVersion>mapMulti(Iterable::forEach)
                 .filter(mv -> mv.getSide().isCorrectSide())

loader/src/main/resources/lang/en_us.json

@@ -17,6 +17,8 @@
   "fml.modloadingissue.discouragedmod": "Mod §e{1}§r §ddiscourages§r the use of §3{0}§r §o{2,vr}§r\n§7Currently, §3{0}§r§7 is §o{3}§r\n§7The reason is:§r §o{4,i18ntranslate}§r",
   "fml.modloadingissue.discouragedmod.proceed": "Proceed at your own risk",
   "fml.modloadingissue.duplicate_mod": "Mod §e{0}§r is present in multiple files: {1}",
+  "fml.modloadingissue.depoverride.unknown_target": "Unknown dependency override target with id §e{0}§r",
+  "fml.modloadingissue.depoverride.unknown_dependency": "Unknown mod §e{0}§r referenced in dependency overrides for mod §e{1}§r",
   "fml.modloading.duplicate_library": "Library §e{3}§r is present in multiple files: {4}",
   "fml.modloading.incompatiblemod.noreason": "§eNo reason provided§r",
   "fml.modloading.discouragedmod.noreason": "§eNo reason provided§r",

loader/src/test/java/net/neoforged/fml/loading/FMLLoaderTest.java

@@ -10,7 +10,10 @@
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import com.electronwill.nightconfig.core.Config;
 import java.nio.file.Files;
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import net.neoforged.fml.ModLoader;
@@ -392,6 +395,46 @@ void testUnsatisfiedNeoForgeRange() throws Exception {
             assertThat(getTranslatedIssues(e.getIssues())).containsOnly("ERROR: Mod testproject requires neoforge 999.6 or above\nCurrently, neoforge is 1\n");
         }
 
+        @Test
+        void testDependencyOverride() throws Exception {
+            installation.setupProductionClient();
+            installation.writeConfig("[dependencyOverrides]", "targetmod = [\"-depmod\", \"-incompatiblemod\"]");
+            installation.buildModJar("depmod.jar").withMod("depmod", "1.0").build();
+            installation.buildModJar("incompatiblemod.jar").withMod("incompatiblemod", "1.0").build();
+            installation.buildModJar("targetmod.jar")
+                    .withModsToml(builder -> {
+                        builder.unlicensedJavaMod();
+                        builder.addMod("targetmod", "1.0", c -> {
+                            var sub = Config.inMemory();
+                            sub.set("modId", "depmod");
+                            sub.set("versionRange", "[2,)");
+                            sub.set("type", "required");
+
+                            var sub2 = Config.inMemory();
+                            sub2.set("modId", "incompatiblemod");
+                            sub2.set("versionRange", "[1,");
+                            sub2.set("type", "incompatible");
+                            c.set("dependencies.targetmod", new ArrayList<>(Arrays.asList(sub, sub2)));
+                        });
+                    })
+                    .build();
+            assertThat(launchAndLoad("forgeclient").issues()).isEmpty();
+        }
+
+        @Test
+        void testInvalidDependencyOverride() throws Exception {
+            installation.setupProductionClient();
+
+            // Test that invalid targets and dependencies warn
+            installation.writeConfig("[dependencyOverrides]", "unknownmod = [\"-testmod\"]", "testmod = [\"+depdoesntexist\"]");
+            installation.buildModJar("testmod.jar").withMod("testmod", "1.0").build();
+
+            var r = launchAndLoad("forgeclient");
+            assertThat(getTranslatedIssues(r.issues())).containsOnly(
+                    "WARNING: Unknown dependency override target with id unknownmod",
+                    "WARNING: Unknown mod depdoesntexist referenced in dependency overrides for mod testmod");
+        }
+
         @Test
         void testDuplicateMods() throws Exception {
             installation.setupProductionClient();

loader/src/test/java/net/neoforged/fml/loading/ModFileBuilder.java

@@ -64,6 +64,10 @@ public ModFileBuilder withTestmodModsToml(Consumer<ModsTomlBuilder> customizer)
         });
     }
 
+    public ModFileBuilder withMod(String id, String version) {
+        return withModsToml(builder -> builder.unlicensedJavaMod().addMod(id, version));
+    }
+
     public ModFileBuilder withModTypeManifest(IModFile.Type type) {
         return withManifest(Map.of(
                 "FMLModType", type.name()));

loader/src/test/java/net/neoforged/fml/loading/SimulatedInstallation.java

@@ -316,6 +316,13 @@ public ModFileBuilder buildModJar(String filename) throws IOException {
         return new ModFileBuilder(path);
     }
 
+    public void writeConfig(String... lines) throws IOException {
+        var file = getGameDir().resolve("config/fml.toml");
+
+        Files.createDirectories(file.getParent());
+        Files.writeString(file, String.join("\n", lines));
+    }
+
     public static void writeJarFile(Path file, IdentifiableContent... content) throws IOException {
         try (var fout = Files.newOutputStream(file)) {
             writeJarFile(fout, content);