used only for resolution tracking

o put tracking filename in TRACKING_FILENAME constant

Extended DependencyManagement to support control of optional flag and enhanced DefaultDependencyCollector and ClassicDependencyManager to make use of it. As a prerequisite, converted optional flag of Dependency from boolean to Boolean to support three-valued logic when inspecting managed dependencies.

Used LocationAwareLogger if supported by logging backend

Bug 394955 - DefaultDependencyCollector generates a very large graph which makes NearestVersionConflictResolver terribly slow

Avoided collecting dependencies for nodes which have an ancestor with the same conflict id, such nodes can never survive conflict resolution regardless of the employed strategy so are nothing but a waste of space and more importantly processing time

Bug 394955 - DefaultDependencyCollector generates a very large graph which makes NearestVersionConflictResolver terribly slow

Optimized hot spots in dependency collection process

Revised hooks in ConflictResolver to allow effecient proxy implementations to select an actual implementation based on the current context

Aligned IniArtifactDescriptorReader with standard Maven behavior and used only GAV for resource lookup

Fixed issues in IniArtifactDataReader (bad exclusions, bad GAV format doc, bad managed dependency scope)

Introduced AbstractForwardingRepositorySystemSession as base class for proxies/decorators

Considered root artifact for detail message of DependencyCollectionException

Tweaked file format for DependencyGraphParser to support more use cases and migrated all graph transformer tests to resource-based graph definitions

Introduced session configuration property "aether.conflictResolver.verbose=true|false" to create desired tree structure during conflict resolution

Partially reverted original fix and restored sharing of child node lists along with docs to explicitly call it out, not only can the new conflict resolver handle this data sharing, it's actually improving performance

Bug 397241 - Conflict resolution miscalculates effective scope for children of nodes with scope conflict

Replaced conceptually flawed JavaEffectiveScopeCalculator and NearestVersionConflictResolver with new ConflictResolver that resolves scope and version conflicts in interleaved way, the new conflict resolver provides hooks to control details of the scope derivation and conflict resolution strategies

Extended CollectRequest to allow specification of root artifact which DefaultDependencyCollector applies as label to root node in case no root dependency is set