General guide CI needs explicit JVM-only runtime selection for Python-enabled samples

[n0tl3ss]

Reproducer and observed source path

The general Test Guides workflow selects <slug>Build for changed guides. With Python-enabled application metadata, that aggregate includes <slug>RunPythonTestScript, which unconditionally depends on local Python fixture staging. The general hosted workflow configures neither an included Python SDK build nor its runtime; staging would stop before application tests. This is a source-backed execution-policy gap, not an observed native-image compile failure.

Add an explicit JVM-only option to the existing CI matrix selector: keep each original aggregate build task and exclude only its dedicated Python runtime task when that task exists. Preserve all JVM/native tasks and Python generation/docs/ZIP/script tasks. Documentation-only apps: [] guides must not acquire an exclusion for an absent task. Default/non-JVM-only selection must remain unchanged.

Fresh regression controls in the shared infrastructure candidate: 12 executed, six pass, one fails and five error before production changes. Existing five matrix tests and the default Python selection control pass; the new explicit JVM-only API/CLI controls fail. Coverage includes implicit and explicit application metadata, documentation-only guides, JVM-only guides, transitive bases and deduplication.

The dedicated Python validation workflow remains generation-only; local complete native-suite results are reported separately. This must not be implemented as skipped-test metadata or a blanket CI script-generation guard. Follow-up Python runtime CI needs its own configured released runtime. Shared prerequisite: #1914.

[n0tl3ss]

Follow-up reproducer for the new review summary on #1915: the JVM-only selector must use the effective application list, not just raw child metadata. A child with explicit Python languages and apps: [] can inherit an application from its base; conversely omitted apps means an empty list, not an implicit application. The expanded selector suite executes 17 tests: 14 pass and three fail before the production fix (direct inherited applications, sorted transitive application inheritance, and omitted applications). Existing default selection, JVM-only controls, documentation-only guides, CLI selection, impact propagation and deduplication remain covered.

A real DefaultGuideParser regression passes independently and confirms that omitted child languages default to Java/Groovy/Kotlin before merging. They do not inherit a base’s Python language. Therefore the fix will preserve explicit Python language selection and mirror the parser’s sorted application-merging pass, rather than add recursive language inheritance or change parser behavior. No currently published guide mismatch was found in the existing metadata; these regressions prevent the latent failure when those supported shapes are used. The shared fix belongs in prerequisite #1914 and will be merged normally into #1915.

[n0tl3ss]

The follow-up fix is published in #1914 commit 1ffbfa7 and normally merged into #1915 at cd13c40. The expanded selector suite now passes 17/17 after reproducing three failures on the old selector. The complete infrastructure suite passes 153 tests with zero failures/errors/skips, including a real-parser control for default child languages and inherited base applications. Fresh hosted checks are pending. Effective empty application lists have no Python runner exclusion; raw apps: [] does not imply effective emptiness if the parser merges in base applications.