prometeu-studio/discussion/workflow/plans/PLN-0108-move-pbs-editor-assistance-behind-optional-language-service.md

id	ticket	title	status	created	ref_decisions	tags
PLN-0108	multi-frontend-compiler-vs-language-services	Move PBS editor assistance behind optional language service	done	2026-07-15	DEC-0041	compiler compiler-general studio lsp editor frontend multi-frontend

Briefing

DEC-0041 allows PBS to keep rich editor assistance, but that behavior must become a PBS-provided optional capability instead of a common frontend requirement. This plan moves PBS completion, hover, signature help, semantic token production, and related editorial behavior behind the optional language-service boundary.

Objective

Expose PBS editor assistance through FrontendProvider.languageService() while preserving current PBS behavior and keeping FrontendProvider.compiler() sufficient for compilation.

Dependencies

• Accepted decision: DEC-0041.
• PLN-0107 should define the documented boundary before final implementation review.
• Existing PBS editorial support classes and LSP bridge behavior.

Scope

• Introduce or extend PBS language-service implementation under the PBS frontend module.
• Make PBSFrontendProvider.languageService() return a PBS language service.
• Keep PBSFrontendProvider.compiler() unchanged as the required compiler path.
• Move PBS-specific editorial calls into the PBS language-service implementation or adapter.
• Preserve existing completion, hover, signature help, semantic token, and documentation behavior for PBS.

Non-Goals

• Change PBS language semantics.
• Add new editor features.
• Rewrite the LSP protocol layer.
• Implement capability-aware LSP fallbacks; that belongs to PLN-0109.
• Split every editor feature into independent top-level service interfaces unless strictly required by local implementation shape.

Execution Method

1. Inspect prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/services/FrontendLanguageService.java and define the minimum capability accessors needed by current PBS editor behavior.
2. Add a PBS language-service implementation in the PBS frontend module, colocated with existing PBS editorial support classes.
3. Move or delegate completion, hover, signature help, and semantic token behavior from PBS-specific bridge code into the PBS language-service implementation without changing output models unless the boundary requires neutral compiler-facing DTOs.
4. Update prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/PBSFrontendProvider.java to return Optional.of(pbsLanguageService).
5. Keep compile/analyze/build paths independent of languageService().
6. Preserve current PBS editorial tests by redirecting setup to the new PBS language-service surface where appropriate.

Acceptance Criteria

• PBS provider exposes a non-empty optional language service.
• PBS compilation still works when only compiler() is used.
• PBS completion, hover, signature help, semantic tokens, and documentation behavior remain equivalent to current behavior.
• Common compiler modules do not instantiate PBS editorial implementation directly.
• No new requirement is introduced for non-PBS frontends to implement editor assistance.

Tests

• Run PBS frontend tests covering editorial support.
• Run LSP tests that currently assert PBS completion, hover, signature help, semantic tokens, and documentation behavior.
• Add or update provider tests proving PBS has a language service while a compile-only provider can omit it.
• Run targeted Gradle tasks for changed compiler frontend and LSP modules.

Affected Artifacts

• prometeu-compiler/prometeu-frontend-api/src/main/java/p/studio/compiler/services/FrontendLanguageService.java
• prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java/p/studio/compiler/PBSFrontendProvider.java
• PBS editorial support classes under prometeu-compiler/frontends/prometeu-frontend-pbs/src/main/java
• Related PBS frontend tests.
• Related LSP bridge tests.