Simplifications for the 3.x lines

[slachiewicz]

Description

Porting the estate to the Maven 4 API (#13302) showed code on the current Maven 3 lines that is buggy, more complicated than it needs to be, or will make the later port harder. This issue tracks the changes that can land on the Maven 3 lines now: they behave the same on Maven 3, and each one shrinks or removes part of the future Maven 4 port. Every item comes from a finished port; its findings are on #13302.

Kinds: bug (found by a port, fix it now), cleanup (behaviour-neutral, smaller port later), deprecation (announce now what Maven 4 removes, so users get a release of warning), seam (a small internal refactor so the port only swaps one method body).

Status

✅ merged · 🔄 pull request open · ⬜ not started (updated 2026-10-07)

The agent/mvn4-api branches rebased on 2026-10-06 include the Done items for maven-acr-plugin, maven-dependency-plugin, maven-enforcer, maven-gpg-plugin and maven-reporting-exec; their findings are on #13302.

Done

24 items

Repository	Kind	Change	Link
✅ maven-doxia-sitetools	seam	Resolve each site descriptor locale through one helper	apache/maven-doxia-sitetools#703
✅ maven-doxia-sitetools	seam	Request skin and site descriptor artifacts from Resolver directly	apache/maven-doxia-sitetools#704
✅ maven-doxia-sitetools	seam	Match skin prerequisites with Resolver's generic version scheme	apache/maven-doxia-sitetools#706
✅ maven-doxia-sitetools	cleanup	Run SiteToolTest offline from a seeded local repository	apache/maven-doxia-sitetools#702
✅ maven-reporting-impl	cleanup	Replace the deprecated API used in AbstractMavenReport	apache/maven-reporting-impl#251
✅ plexus-archiver	bug	Archivers created without a container can unpack (ServiceLoaderArchiverManager)	codehaus-plexus/plexus-archiver#500
✅ maven-dependency-tree	cleanup	Planned-retirement notice: the Maven 4 port showed it is mostly redundant with Resolver	apache/maven-dependency-tree#151
✅ maven-common-artifact-filters	bug	ArtifactTransitivityFilter.transitiveArtifacts is never initialised, so its constructor throws NullPointerException on the first resolved dependency	apache/maven-common-artifact-filters#131
✅ maven-resolver-ant-tasks	bug	AntRepoSys.getSettings() throws NullPointerException when settings.xml cannot be read	apache/maven-resolver-ant-tasks#196
✅ maven-release	bug	The forked build's release-settings*.xml is written with FileWriter, in the platform charset, under a UTF-8 header	apache/maven-release#1514
✅ maven-archetype	bug	DefaultPomManager merges dependencies in HashMap order	apache/maven-archetype#1042
✅ maven-reporting-exec	bug	setReportPlugins shares the model's report list instead of copying it	apache/maven-reporting-exec#168
✅ maven-changelog-plugin, maven-toolchains-plugin	cleanup	@Component → @Inject	apache/maven-changelog-plugin#252, apache/maven-toolchains-plugin#202
✅ maven-ejb-plugin, maven-rar-plugin	cleanup	Unit tests on JUnit 5 without AbstractMojoTestCase	apache/maven-ejb-plugin#242, apache/maven-rar-plugin#182
✅ maven-rar-plugin	cleanup	An IT with real dependencies: no IT had one, so a port that copied nothing stayed green	apache/maven-rar-plugin#181
✅ several (acr, ejb, rar, enforcer, release, archetype)	cleanup	plexus-utils → JDK or commons-lang3 where the semantics are identical	apache/maven-acr-plugin#156, apache/maven-ejb-plugin#241, apache/maven-rar-plugin#180, apache/maven-enforcer#1048, apache/maven-release#1516, apache/maven-archetype#1043
✅ maven-acr-plugin	bug	The user's excludes list is changed in place	apache/maven-acr-plugin#155
✅ maven-acr-plugin	seam	Register the app-client artifact handler and lifecycle mapping as Sisu-indexed classes instead of Plexus components.xml, as maven-rar-plugin does	apache/maven-acr-plugin#157
✅ maven-acr-plugin, maven-rar-plugin	bug	A project that loads the plugin through <build><extensions> runs the latest released packaging goal instead of the loaded one	apache/maven-acr-plugin#157, apache/maven-rar-plugin#183
✅ maven-dependency-plugin, maven-project-info-reports-plugin	cleanup	Replace maven-dependency-tree with Maven Resolver	apache/maven-dependency-plugin#1712, apache/maven-project-info-reports-plugin#670
✅ maven-enforcer	bug	EnforcerRuleUtils.resolvePlugins changes the effective model's Plugin objects in place	apache/maven-enforcer#1046
✅ maven-enforcer	deprecation	Make the existing warning for EnforcerRule, EnforcerRule2 and EnforcerRuleHelper name enforcer 4.0.0 as the removal point	apache/maven-enforcer#1047
✅ maven-jmod-plugin, maven-jdeprscan-plugin	cleanup	Drop the reflection around ToolchainManager.getToolchains, which the interface has	apache/maven-jmod-plugin#121, apache/maven-jdeprscan-plugin#94
✅ maven-gpg-plugin	deprecation	settings parameter in favour of the session's settings	apache/maven-gpg-plugin#346

In progress

Repository	Kind	Change	Link
🔄 maven-toolchains-plugin	bug	Toolchain discovery returns nothing when one JDK cannot be read, instead of skipping that JDK	apache/maven-toolchains-plugin#196 (issue apache/maven-toolchains-plugin#191)
🔄 maven-mapping	deprecation	Document only the file-name tokens that survive; ArtifactHandler tokens such as @{packaging}@ stop resolving on Maven 4	apache/maven-war-plugin#666, apache/maven-ear-plugin#569
🔄 maven-doxia-sitetools	deprecation	Artifact-based skin methods in SiteRenderer and SiteRenderingContext, with File/Path overloads	apache/maven-doxia-sitetools#707
🔄 maven-reporting-impl, maven-rar-plugin	cleanup	${basedir} → ${project.basedir} in parameter defaults of mojos that require a project	apache/maven-reporting-impl#255, apache/maven-rar-plugin#179
🔄 maven-jdeps-plugin	cleanup	Drop the reflection around ToolchainManager.getToolchains, which the interface has	apache/maven-jdeps-plugin#109
🔄 maven-release	deprecation	DefaultReleaseManagerListener(Log) in favour of slf4j overloads	apache/maven-release#1515
🔄 maven-reporting-impl	deprecation	Protected fields reactorProjects, repoSession, remoteProjectRepositories, siteTool, siteRenderer in favour of getters; five report plugins read them directly	apache/maven-reporting-impl#256
🔄 maven-plugin-tools	deprecation	PluginToolsRequest.get/setRepoSession, PluginHelpGenerator.setVelocityComponent	apache/maven-plugin-tools#1223, apache/maven-plugin-tools#1224 (3.x)
🔄 maven-surefire	cleanup	Create plexus-java's LocationManager with new instead of injecting it	apache/maven-surefire#3499
🔄 maven-jarsigner-plugin	deprecation	settings field in favour of the session's settings	apache/maven-jarsigner-plugin#176
🔄 maven-archetype	cleanup	Replace plexus-velocity's VelocityComponent with a plain VelocityEngine	apache/maven-archetype#1044
🔄 maven-plugin-tools	cleanup	Unpack sources jars with java.util.zip instead of plexus-archiver's ArchiverManager	apache/maven-plugin-tools#1225, apache/maven-plugin-tools#1226 (3.x)
🔄 maven-reporting-exec	seam	coreSession(request) / coreProject(request) helpers	apache/maven-reporting-exec#169
🔄 maven-scm-publish-plugin	seam	Inline getConfiguredRepository with an injected SettingsDecrypter and drop maven-release-manager	apache/maven-scm-publish-plugin#167
🔄 maven-enforcer, maven-release	seam	One helper per repository for the original model and project file	apache/maven-enforcer#1049, apache/maven-release#1517
🔄 maven-release	seam	Pom* view interfaces over the DomTrip classes	apache/maven-release#1518
🔄 maven-dependency-analyzer	seam	Collect dependencies directly instead of the DependencyGraphProject extends MavenProject workaround	apache/maven-dependency-analyzer#306
🔄 maven-indexer	seam	Replace ArtifactContext.getPomModel() with a small value type (name, description, packaging); indexer-core then drops maven-model and needs no Maven 4 port	apache/maven-indexer#808

To do

Repository	Kind	Change
⬜ maven-plugin-tools	cleanup	Replace plexus-velocity's VelocityComponent with a plain VelocityEngine in HelpGeneratorMojo, after apache/maven-plugin-tools#1223
⬜ maven-doxia	bug	MarkdownHtmlParser is registered as a Parser through its bare @Named, so every parser map lists it next to the real formats (apache/maven-doxia#1111)

Not now

These wait for an API request on #13302 and must not be deprecated before a replacement exists: maven-common-artifact-filters actTransitively; maven-dependency-tree premanaged getters and collector setters; enforcer rules requireUpperBoundDeps, banDynamicVersions and requireProfileIdsExist.

Dropped: building an ScmManager (apache/maven-scm#1418), the Doxia parser managers (apache/maven-doxia#1110) and a CompilerManager (codehaus-plexus/plexus-compiler#524) without Sisu through ServiceLoader. Once Maven 4 API mojos can inject Sisu components from their plugin realm through javax.inject (#13326, planned for 4.0.0-rc-8), the ports inject these managers as they do on Maven 3.

Also dropped: a maven-archetype helper for the project reads in FilesetArchetypeCreator. The Maven 4 port rewrites that class for immutable models anyway, so a helper would not make the port smaller.

[slawekjaranowski]

@slachiewicz thanks for such initiative ... We have many linked PR generated by AI (I suppose), I would be happy to not only AI check it ... but also human look at it