001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.eclipse.aether.util.graph.manager; 020 021import java.util.ArrayList; 022import java.util.Collection; 023 024import org.eclipse.aether.collection.DependencyCollectionContext; 025import org.eclipse.aether.collection.DependencyManager; 026import org.eclipse.aether.graph.Exclusion; 027import org.eclipse.aether.scope.ScopeManager; 028import org.eclipse.aether.scope.SystemDependencyScope; 029 030/** 031 * A dependency manager that mimics the way Maven 2.x works for backward compatibility. 032 * 033 * <h2>Overview</h2> 034 * <p> 035 * This manager was used throughout all Maven 3.x versions for backward compatibility reasons. 036 * It provides the exact same dependency management behavior as Maven 2.x, which differs 037 * significantly from modern dependency management approaches. 038 * </p> 039 * 040 * <h2>Key Characteristics</h2> 041 * <ul> 042 * <li><strong>Exclusion Handling:</strong> Ignores exclusions introduced by direct dependencies</li> 043 * <li><strong>Management Scope:</strong> Only obeys root management, ignoring intermediate management</li> 044 * <li><strong>Depth Behavior:</strong> {@code deriveUntil=2}, {@code applyFrom=2} with special "hop" at {@code depth=1}</li> 045 * <li><strong>Level 1 Skip:</strong> Ignores context from depth=1 for Maven 2.x compatibility</li> 046 * </ul> 047 * 048 * <h2>When to Use</h2> 049 * <p> 050 * Use this manager when you need exact Maven 2.x compatibility behavior or when working 051 * with legacy projects that depend on Maven 2.x dependency resolution semantics. 052 * </p> 053 * 054 * <h2>Comparison with Other Managers</h2> 055 * <p> 056 * Unlike {@link TransitiveDependencyManager} and {@link DefaultDependencyManager}, this manager 057 * deliberately ignores certain dependency management rules to maintain backward compatibility. 058 * See {@code MavenITmng4720DependencyManagementExclusionMergeTest} for behavioral differences. 059 * </p> 060 * 061 * @see TransitiveDependencyManager 062 * @see DefaultDependencyManager 063 */ 064public final class ClassicDependencyManager extends AbstractDependencyManager { 065 /** 066 * Creates a new dependency manager without any management information. 067 * 068 * @deprecated Use {@link #ClassicDependencyManager(ScopeManager)} instead to provide 069 * application-specific scope management. This constructor uses legacy system 070 * dependency scope handling which may not be appropriate for all use cases. 071 */ 072 @Deprecated 073 public ClassicDependencyManager() { 074 this(null); 075 } 076 077 /** 078 * Creates a new dependency manager without any management information. 079 * <p> 080 * This constructor initializes the manager with Maven 2.x compatible behavior: 081 * <ul> 082 * <li>deriveUntil = 2 (collect rules only from root level)</li> 083 * <li>applyFrom = 2 (apply rules starting from depth 2)</li> 084 * <li>Special depth=1 handling for backward compatibility</li> 085 * </ul> 086 * 087 * @param scopeManager application-specific scope manager for handling system dependencies, 088 * may be null to use legacy system dependency scope handling 089 * @since 2.0.12 090 */ 091 public ClassicDependencyManager(ScopeManager scopeManager) { 092 super(2, 2, scopeManager); 093 } 094 095 @SuppressWarnings("checkstyle:ParameterNumber") 096 private ClassicDependencyManager( 097 ArrayList<AbstractDependencyManager> path, 098 int depth, 099 int deriveUntil, 100 int applyFrom, 101 MMap<Key, String> managedVersions, 102 MMap<Key, String> managedScopes, 103 MMap<Key, Boolean> managedOptionals, 104 MMap<Key, String> managedLocalPaths, 105 MMap<Key, Holder<Collection<Exclusion>>> managedExclusions, 106 SystemDependencyScope systemDependencyScope) { 107 super( 108 path, 109 depth, 110 deriveUntil, 111 applyFrom, 112 managedVersions, 113 managedScopes, 114 managedOptionals, 115 managedLocalPaths, 116 managedExclusions, 117 systemDependencyScope); 118 } 119 120 /** 121 * Derives a child manager with Maven 2.x compatibility behavior. 122 * <p> 123 * <strong>Critical Maven 2.x Compatibility:</strong> This method implements a special 124 * "hop" at depth=1 that skips dependency management collection at that level. This 125 * behavior is essential for Maven 2.x compatibility and is verified by integration tests. 126 * </p> 127 * <p> 128 * <strong>Why the depth=1 skip is necessary:</strong> Maven 2.x did not collect dependency 129 * management from first-level dependencies, only from the root. Removing this skip would 130 * break backward compatibility with Maven 2.x projects. 131 * </p> 132 * 133 * @param context the dependency collection context 134 * @return a new child manager or the current instance with passed-through management 135 * @see <a href="https://github.com/apache/maven-integration-testing/blob/master/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng4720DependencyManagementExclusionMergeTest.java">MNG-4720 Integration Test</a> 136 */ 137 @Override 138 public DependencyManager deriveChildManager(DependencyCollectionContext context) { 139 // MNG-4720: Maven2 backward compatibility 140 // Removing this IF makes one IT fail here (read comment above): 141 // https://github.com/apache/maven-integration-testing/blob/b4e8fd52b99a058336f9c7c5ec44fdbc1427759c/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng4720DependencyManagementExclusionMergeTest.java#L67 142 // Skipping level=1 (maven2 compatibility); see MavenITmng4720DependencyManagementExclusionMergeTest 143 if (depth == 1) { 144 return newInstance(managedVersions, managedScopes, managedOptionals, managedLocalPaths, managedExclusions); 145 } 146 return super.deriveChildManager(context); 147 } 148 149 @Override 150 protected DependencyManager newInstance( 151 MMap<Key, String> managedVersions, 152 MMap<Key, String> managedScopes, 153 MMap<Key, Boolean> managedOptionals, 154 MMap<Key, String> managedLocalPaths, 155 MMap<Key, Holder<Collection<Exclusion>>> managedExclusions) { 156 ArrayList<AbstractDependencyManager> path = new ArrayList<>(this.path); 157 path.add(this); 158 return new ClassicDependencyManager( 159 path, 160 depth + 1, 161 deriveUntil, 162 applyFrom, 163 managedVersions, 164 managedScopes, 165 managedOptionals, 166 managedLocalPaths, 167 managedExclusions, 168 systemDependencyScope); 169 } 170}