Concurrent builder skips 'verify' phase when running 'mvn install'; missing --skip-tests option

[gnodet]

Problem

In the new phase tree introduced in Maven 4, the install and deploy phases depend on package but not on verify. This means:

1. The concurrent builder (-b concurrent) silently skips verify when running mvn install, because there is no declared dependency between install and verify in the DAG.
2. The classic sequential builder still executes verify incidentally (because phases are flattened in order), but this is an accidental property of the flattening, not a semantic guarantee.

This was flagged as a disruptive regression by @rmannibucau: users running mvn install expect verification (unit tests, integration tests) to have run before the artifact is installed to the local repository.

Root Cause

In DefaultLifecycleRegistry.DefaultLifecycle.phases(), the phase tree is:

EACH
├── VALIDATE / INITIALIZE
├── BUILD
│   ├── SOURCES / RESOURCES
│   ├── COMPILE (after SOURCES)
│   ├── READY (after COMPILE, after RESOURCES)
│   └── PACKAGE (after READY)
├── VERIFY                          ← depends on VALIDATE only
│   ├── UNIT_TEST / TEST / ...
│   └── INTEGRATION_TEST
├── INSTALL  (after PACKAGE)        ← ⚠ should depend on VERIFY
└── DEPLOY   (after PACKAGE)        ← ⚠ should depend on VERIFY

INSTALL and DEPLOY declare after(PACKAGE) but not after(VERIFY).

Fix

Change INSTALL and DEPLOY to depend on VERIFY instead of PACKAGE:

phase(INSTALL, after(VERIFY)),
phase(DEPLOY, after(VERIFY)))));\n```

This is semantically correct: you should not install an artifact that has not been verified. `VERIFY` itself already depends transitively on `PACKAGE` (via the `BUILD` subtree), so the full build order is preserved.

## Planned work

- **4.0.x**: Fix `install` → `verify` and `deploy` → `verify` dependencies → #13231
- **4.1.0**: Same DAG fix → #13232

_Reported by Guillaume Nodet_

[gnodet]

Follow-up: --skip-phases for 4.1.0

The second part of this fix (targeted at 4.1.0 / master) is the introduction of a proper --skip-phases CLI option as a plugin-agnostic replacement for ad-hoc conventions like -DskipTests.

Motivation / Use Cases

The current -DskipTests convention has several problems:

• Not universal: it works for Surefire but not for all plugins (e.g. does not skip integration tests run by Failsafe)
• Not composable: skipping both unit tests and integration tests requires -DskipTests -DskipITs or -Dmaven.test.skip=true, with inconsistent semantics across plugins
• Convention-based: each plugin must opt in; there is no first-class Maven mechanism

Real-world scenarios where skipping test phases is legitimate:

1. Large projects with long test suites (Camel, Quarkus): a full build can take hours. These projects rely on green CI (which tests multiple JDK/platform combinations) rather than local test runs. Running tests locally only validates one specific environment anyway.

2. Release builds: for projects with flaky tests or slow test suites, the release is cut from a commit that already passed CI. Re-running tests locally during the release process adds time and exposure to environmental issues without adding meaningful safety.

3. Consuming a dependency snapshot: when you want to test a third-party SNAPSHOT in your own project, you care about the generated artifact — not about running that dependency's own test suite. You want to mvn install --skip-phases=test,integration-test the dependency, then run your own project's tests against the freshly installed artifact.

Design

Syntax:

mvn verify --skip-phases=test,integration-test

Comma-separated list of phase names to skip. Option name: --skip-phases (long only, no short alias).

Semantics: Phase skipping is mojo-level inhibition, not graph surgery. The skipped phases remain in the DAG — their predecessors and successors are unaffected. Only the mojo executions bound to a skipped phase are suppressed. This mirrors what -DskipTests does for Surefire, but as a first-class CLI feature that works uniformly across all plugins.

Example: --skip-phases=test,integration-test on mvn verify runs compile, resources, test-compile, test-resources, package, and verify — but skips all mojos bound to test and integration-test.

Implementation touch points:

1. MavenOptions (API) — add Optional<List<String>> skippedPhases()
2. CommonsCliMavenOptions + CLIManager — register the option, parse comma-separated values
3. LayeredMavenOptions — merge via collectListIfPresentOrEmpty
4. MavenExecutionRequest — add getSkippedPhases() / setSkippedPhases()
5. MavenInvoker.populateRequest() — wire option → request
6. BuildPlanExecutor.plan() — when attaching mojos to a BuildStep, skip if resolvedPhase is in the skipped set
7. The sequential builder path (single-threaded / multi-threaded) needs the same guard

The skipped-phase set should be propagated via MavenSession so that both the concurrent and sequential builder paths can access it uniformly without duplicating the check.