[rubenvdlinde]

What changed

DemoShowcasesService::installShowcase (public, signature unchanged) reads as named steps. This PR touches a different method than the open descriptor / partition split of the same file and merges cleanly with it.

• assertInstallable (unknown id, missing archive — both before the lock is taken, as before).
• acquireInstallLock (the same "already in progress" refusal, with the lock exception as its cause) and releaseInstallLock, still in a finally so every install attempt releases the lock.
• installLocked reuses an existing install, replaces it when forced, or installs fresh; the language and force flag travel as a ShowcaseInstallOptions.

Allowed and refused outcomes, the lock key and mode, and the order of the lock, uninstall, insert and marker writes are unchanged.

Characterisation tests

tests/Unit/Service/DemoShowcasesInstallGoldenTest.php was committed first, against the old code, and passes before and after: unknown ids and missing archives refused before the lock, a busy lock refused (with its cause) and not released, an existing install reused under the lock, a forced reinstall uninstalling before inserting, a fresh install marked and released, and a failed install still releasing the lock. Mutation check: ignoring the force flag on the old code turned the reuse golden red; restored before committing.

What ran

• vendor/bin/phpunit -c phpunit.xml --no-coverage tests/Unit: 2751 tests OK (13 skipped, as on development).
• vendor/bin/phpcs (two warnings about missing spec tags on getDataDir / setDataDirForTesting, the same as on development) and vendor/bin/phpstan analyse on the touched lib files: no errors.

Figures (touched files lib/Service/DemoShowcasesService.php, lib/Service/ShowcaseInstallOptions.php)

	before	after
installShowcase	complexity 7, 48 lines, 3 parameters	complexity 1, 13 lines (signature unchanged)
units over complexity 5, whole file	5 units, 171 lines	4 units, 123 lines (the rest is split in the other open PR)
units over 15 lines of code	9 units, 313 lines	8 units, 265 lines
units over 2 parameters	3 units, 95 lines	3 units, 61 lines

App-wide: unit complexity 4.02 → 4.05, unit interfacing 3.14 → 3.15.

Maintainability floor: compare against development holds.

AI-assisted: prepared with Claude Code (claude-opus-5-5); reviewed by a maintainer before merge.

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Generated by Claude Code