Fix #12530: add mvnup upgrade strategies for Maven 4 known compatibility issues

[gnodet]

Summary

Adds 4 new mvnup upgrade strategies to address Maven 4 known compatibility issues from the maven4-testing project:

• old-compiler-plugin-errorprone: Update maven-compiler-plugin minimum to 3.11.0 (older versions can't find ErrorProne plug-in under Maven 4 classloading)
• beta-plugin-api-break: Detect and upgrade Maven 4 pre-release plugin versions (4.0.0-beta-1, 4.0.0-alpha-*, etc.) that use API methods renamed/removed before RC
• old-scala-tools-plugin: Migrate org.scala-tools:maven-scala-plugin → net.alchim31.maven:scala-maven-plugin:4.9.5 (unmaintained since 2011)
• duplicated-pom-tag: New DuplicateElementStrategy that removes duplicate XML elements (<artifactId>, <properties>, etc.) that Maven 4's stricter POM parser rejects

The remaining 4 strategies from the issue already existed:

• scala-maven-plugin#911 → already in PLUGIN_UPGRADES at 4.9.5
• ancient-enforcer-plugin → already in PLUGIN_UPGRADES at 3.5.0
• exec-plugin-getcontainer → already in PLUGIN_UPGRADES at 3.5.0
• duplicate-dependency-declarations → already in DeduplicateDependenciesStrategy

Changes

File	Change
PluginUpgradeStrategy.java	Updated compiler min to 3.11.0, added isMaven4PreRelease() detection, added PluginMigration support with migratePlugin() method
PluginMigration.java	New record for plugin groupId/artifactId migrations
DuplicateElementStrategy.java	New strategy (priority 21) that recursively removes duplicate XML elements using last-wins semantics, skipping list containers
PluginUpgradeStrategyTest.java	13 new tests: 9 for pre-release detection, 4 for plugin migration
DuplicateElementStrategyTest.java	18 new tests covering applicability, element removal, nesting, list container skipping

Test plan

• All 476 mvnup tests pass (0 failures)
• Format check passes (-Psourcecheck validate)
• CI build passes

🤖 Generated with Claude Code

[gnodet]

Code Review

Well-implemented PR that adds four new mvnup upgrade strategies for Maven 4 compatibility. The pre-release detection logic is correct, the DuplicateElementStrategy handles list containers properly, and the test coverage is solid with 31 new tests. All 8 strategies from issue #12530 are accounted for (4 new, 4 already existing).

Three minor notes (non-blocking):

• buildElementPath(Element parent, Element child) — the child parameter is never used; the method only walks up from parent. Either remove the parameter or append the child's name to the path for a more complete log message.
• getPluginMigrationsMap() and getPluginUpgradesMap() rebuild a new HashMap on every call. With only one migration entry this is negligible, but could be hoisted to static fields for consistency.
• The deduplication of getPluginUpgradesMap() (now derived from the PLUGIN_UPGRADES list via stream) is a good cleanup that eliminates a previous source of inconsistency.

LGTM.

This review was generated by an AI agent and may contain inaccuracies. Please verify all suggestions before applying.

Claude Code on behalf of gnodet

[gnodet]

Thanks for the review! Addressed all three points:

1. buildElementPath unused child parameter — Removed the unused parameter. Method now takes only the parent element. (80b938e)

2. getPluginMigrationsMap() rebuilt on every call — Hoisted to a static final field initialized once from PLUGIN_MIGRATIONS. (80b938e)

3. getPluginUpgradesMap() dedup — Already done in c88b27e (derives from PLUGIN_UPGRADES list via stream, eliminating the previous hand-maintained duplicate map).

[gnodet]

Code Review (Re-review)

All three items from the previous review have been addressed in commit 80b938e:

1. Unused child parameter in buildElementPath() — ✅ Removed.
2. PLUGIN_MIGRATIONS_MAP rebuilt on every call — ✅ Hoisted to a static final field.
3. getPluginUpgradesMap() deduplication — ✅ Already derived from PLUGIN_UPGRADES list, eliminating the hand-maintained duplicate map.

One remaining minor note (non-blocking):

• getPluginUpgradesMap() still rebuilds a HashMap from PLUGIN_UPGRADES.stream() on every call (once per POM). Negligible with ~20 entries, but hoisting to a static final would be consistent with how PLUGIN_MIGRATIONS_MAP was handled.

The review-feedback commit is minimal and scoped precisely to the requested changes. LGTM.

This review was generated by an AI agent and may contain inaccuracies. Please verify all suggestions before applying.

Claude Code on behalf of gnodet