[devkit] IJPL-246844 Attach IntelliJ SDK sources automatically on Gradle sync

Add AuxiliaryArtifactProvider allowing for contributing additional domain-specific artifact coordinations to be resolved by Gradle.

(cherry picked from commit a3abc045e14a4b5fe8d7c3a43047e539e27382eb)
IJ-MR-210892

GitOrigin-RevId: eee9d1adb0c95000b643ad216c0c88e53092d882

plugins/gradle/tooling-extension-impl/src/com/intellij/gradle/toolingExtension/impl/model/dependencyModel/GradleDependencyResolver.java

@@ -1,8 +1,9 @@
-// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.gradle.toolingExtension.impl.model.dependencyModel;
 
 import com.intellij.gradle.toolingExtension.impl.model.dependencyDownloadPolicyModel.GradleDependencyDownloadPolicy;
 import com.intellij.gradle.toolingExtension.impl.model.dependencyDownloadPolicyModel.GradleDependencyDownloadPolicyCache;
+import com.intellij.gradle.toolingExtension.impl.model.dependencyModel.auxiliary.AuxiliaryArtifactProvider;
 import com.intellij.gradle.toolingExtension.impl.model.dependencyModel.auxiliary.AuxiliaryArtifactResolver;
 import com.intellij.gradle.toolingExtension.impl.model.dependencyModel.auxiliary.AuxiliaryArtifactResolverImpl;
 import com.intellij.gradle.toolingExtension.impl.model.dependencyModel.auxiliary.AuxiliaryConfigurationArtifacts;
@@ -58,6 +59,7 @@ import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.Map;
+import java.util.ServiceLoader;
 import java.util.Set;
 import java.util.function.Predicate;
 import java.util.regex.Pattern;
@@ -186,6 +188,7 @@ public final class GradleDependencyResolver {
     // Here we collect java doc and source files for a given dependencies
     AuxiliaryConfigurationArtifacts auxiliaryArtifacts = getAuxiliaryArtifactResolver(resolvedArtifacts, allowedDependencyGroups)
       .resolve(configuration);
+    auxiliaryArtifacts = resolveSupplementaryArtifacts(configuration, auxiliaryArtifacts);
     Set<String> resolvedFiles = new HashSet<>();
     Collection<ExternalDependency> artifactDependencies = resolveArtifactDependencies(
       resolvedFiles, resolvedArtifacts, auxiliaryArtifacts, transformedProjectDependenciesResultMap
@@ -509,6 +512,27 @@ public final class GradleDependencyResolver {
     }
   }
 
+  private @NotNull AuxiliaryConfigurationArtifacts resolveSupplementaryArtifacts(
+    @NotNull Configuration configuration,
+    @NotNull AuxiliaryConfigurationArtifacts primaryArtifacts
+  ) {
+    if (!myDownloadPolicy.isDownloadSources() && !myDownloadPolicy.isDownloadJavadoc()) {
+      return primaryArtifacts;
+    }
+    ServiceLoader<AuxiliaryArtifactProvider> providers = ServiceLoader.load(
+      AuxiliaryArtifactProvider.class, AuxiliaryArtifactProvider.class.getClassLoader());
+    for (AuxiliaryArtifactProvider provider : providers) {
+      try {
+        AuxiliaryConfigurationArtifacts additional = provider.resolve(myProject, configuration, myDownloadPolicy);
+        primaryArtifacts = primaryArtifacts.mergeWith(additional);
+      }
+      catch (Exception ignore) {
+        // supplementary providers should not break the main resolution
+      }
+    }
+    return primaryArtifacts;
+  }
+
   private static boolean isIvyRepositoryUsed(@NotNull Project project) {
     for (ArtifactRepository repository : project.getRepositories()) {
       if (repository instanceof IvyArtifactRepository) {

plugins/gradle/tooling-extension-impl/src/com/intellij/gradle/toolingExtension/impl/model/dependencyModel/auxiliary/AuxiliaryArtifactProvider.java

@@ -0,0 +1,28 @@
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.gradle.toolingExtension.impl.model.dependencyModel.auxiliary;
+
+import com.intellij.gradle.toolingExtension.impl.model.dependencyDownloadPolicyModel.GradleDependencyDownloadPolicy;
+import org.gradle.api.Project;
+import org.gradle.api.artifacts.Configuration;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Service provider interface for resolving additional source and Javadoc artifacts
+ * that the standard {@link AuxiliaryArtifactResolver} cannot find.
+ * <p>
+ * This is useful for dependencies whose source artifacts are published under
+ * different Maven coordinates than the main artifact (e.g., IntelliJ Platform dependencies).
+ * <p>
+ * Implementations are discovered via {@link java.util.ServiceLoader}.
+ */
+@ApiStatus.Internal
+public interface AuxiliaryArtifactProvider {
+
+  @NotNull
+  AuxiliaryConfigurationArtifacts resolve(
+    @NotNull Project project,
+    @NotNull Configuration configuration,
+    @NotNull GradleDependencyDownloadPolicy policy
+  );
+}

plugins/gradle/tooling-extension-impl/src/com/intellij/gradle/toolingExtension/impl/model/dependencyModel/auxiliary/AuxiliaryConfigurationArtifacts.java

@@ -1,4 +1,4 @@
-// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.gradle.toolingExtension.impl.model.dependencyModel.auxiliary;
 
 import org.gradle.api.artifacts.component.ComponentIdentifier;
@@ -9,7 +9,9 @@ import org.jetbrains.annotations.VisibleForTesting;
 import org.jetbrains.plugins.gradle.tooling.util.StringUtils;
 
 import java.io.File;
+import java.util.Collections;
 import java.util.Comparator;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
@@ -20,6 +22,9 @@ import java.util.regex.Pattern;
 @ApiStatus.Internal
 public class AuxiliaryConfigurationArtifacts {
 
+  public static final AuxiliaryConfigurationArtifacts EMPTY =
+    new AuxiliaryConfigurationArtifacts(Collections.emptyMap(), Collections.emptyMap());
+
   private static final Pattern PUNCTUATION_IN_SUFFIX_PATTERN = Pattern.compile("[\\p{Punct}\\s]+$");
 
   private final @NotNull Map<ComponentIdentifier, Set<File>> sources;
@@ -117,4 +122,21 @@ public class AuxiliaryConfigurationArtifacts {
 
     return shortlistedAuxiliariesBySuffixlessName.firstEntry().getValue();
   }
+
+  /**
+   * Merges this instance with additional artifacts. Primary (this) results take precedence.
+   */
+  public @NotNull AuxiliaryConfigurationArtifacts mergeWith(@NotNull AuxiliaryConfigurationArtifacts other) {
+    if (other == EMPTY) return this;
+    if (this == EMPTY) return other;
+    Map<ComponentIdentifier, Set<File>> mergedSources = new HashMap<>(this.sources);
+    for (Map.Entry<ComponentIdentifier, Set<File>> entry : other.sources.entrySet()) {
+      mergedSources.putIfAbsent(entry.getKey(), entry.getValue());
+    }
+    Map<ComponentIdentifier, Set<File>> mergedJavadocs = new HashMap<>(this.javadocs);
+    for (Map.Entry<ComponentIdentifier, Set<File>> entry : other.javadocs.entrySet()) {
+      mergedJavadocs.putIfAbsent(entry.getKey(), entry.getValue());
+    }
+    return new AuxiliaryConfigurationArtifacts(mergedSources, mergedJavadocs);
+  }
 }