Simplify Prisma 7/8 language server routing via server-side filtering

[StevenMcClankerton]

Overview

Replaces the client-side per-document routing between the legacy language server and the Prisma Next language server with content-based filtering inside the servers themselves.

Both servers now receive every open Prisma document through standard LSP document synchronization and each decides locally, from the // use prisma-next directive, whether to respond:

• the legacy server ignores marked documents (publishes empty diagnostics, returns empty feature results, excludes them from multi-file schema composition),
• the Prisma Next server (prisma lsp, requires prisma@8.0.0-rc.8-dev.2 or later) applies the mirror-image filter.

The two servers share only this directive convention — neither depends on the other.

Why

Routing by document content is a stateless decision each server can make per request. Making it a client-side ownership-transfer problem required an ownership coordinator with revisions and prepare/commit transitions, gating middlewares on both clients, manual didOpen/didClose bookkeeping, and a lifecycle controller — all to migrate documents between live clients while their content changes mid-flight. All of that is deleted (net −1,040 lines):

• documentOwnership.ts, documentRouting.ts, legacyClientMiddleware.ts, prismaNextClientMiddleware.ts, languageServerLifecycle.ts, prismaNextClientRegistry.ts removed,
• the plugin returns to its pre-routing shape: plain document selector, middleware only for the Prisma 6 diagnostic prompts,
• new slim prismaNextClients.ts: at most one prisma lsp client per workspace folder, started the first time an open document under that folder carries the directive; lifecycle is monotonic — no per-document transfer.

Directive toggling still switches servers instantly (both already track the document), pin/unpin to Prisma 6, lazy legacy start, workspace-trust checks, CLI lookup at the workspace root, and no-auto-restart-after-crash semantics are all preserved.

Also removes the obsolete snippet code-action workaround for #311 (prisma.applySnippetWorkspaceEdit, isSnippetEdit, and the provideCodeActions middleware): no shipped server emits the empty-block edits it rewrote — the create-new-block quick fixes were removed from the language server in #1743, and the bundled Prisma 6 server (6.19.0) does not contain them either.

Testing

• tsc --noEmit, eslint, and language-server unit tests (227) pass locally.
• The behavioral e2e suites (workspace.test.ts side-by-side completions, prismaNext.test.ts directive toggling) exercise the new model directly; they could not be run locally (environment cannot launch VS Code), so CI is the gate for them.

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• packages/vscode/src/plugins/prisma-language-server/index.ts
• packages/vscode/src/util.ts

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Summary by CodeRabbit

• New Features

  • Updated VS Code document handling so both language servers can receive open Prisma documents and determine locally whether to respond.
  • Added support for one Prisma Next server per workspace folder.
  • Clarified behavior for the // use prisma-next directive and Prisma 6 pinning.
  • Added retry support after failed Prisma Next server launches.

• Bug Fixes

  • Simplified language server restart and shutdown handling.

• Documentation

  • Updated document routing and language server process-count guidance.
  • Documented the required Prisma version for Prisma Next support.

Walkthrough

The VS Code extension now synchronizes open Prisma documents with the legacy server and Prisma Next servers. Each server filters documents using the // use prisma-next directive. Prisma Next clients start per workspace folder and use the local Prisma CLI. Legacy server lifecycle and document ownership coordinators were removed. Restart and shutdown flows now operate directly. Documentation reflects the new routing, process counts, Prisma version requirement, and Prisma 6 pinning behavior.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 11 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly identifies the main change: replacing client-side Prisma 7/8 language server routing with server-side filtering.
Description check	✅ Passed	The description directly explains the server-side filtering model, removed routing machinery, preserved behavior, and testing status.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch prisma-next-local-routing

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch prisma-next-local-routing

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Actionable comments posted: 5

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Inline comments:
In `@docs/language-server.md`:
- Around line 39-42: Update the synchronization description near the legacy and
Prisma Next language-server discussion to state that each running server
receives every open Prisma document, rather than claiming both always do.
Preserve the existing explanation of conditional server startup and clarify that
a server that has not started cannot receive documents.

In `@packages/vscode/src/plugins/prisma-language-server/index.ts`:
- Around line 186-191: Serialize Prisma 6 diagnostic handling in
handleDiagnostics by awaiting or chaining each prisma6Handling.handleDiagnostic
call before starting the next, while preserving the final next(uri, diagnostics)
callback after all diagnostics are processed.

In `@packages/vscode/src/plugins/prisma-language-server/prismaNextClients.ts`:
- Around line 45-55: Update ensureClientFor to track failed workspaceFolder
startups with a timestamp or failure counter and skip automatic retries during a
cooldown period, while preserving the existing pending-client deduplication.
Clear the failure state after a successful start, and allow the explicit restart
command to bypass the cooldown; use the existing clients map and start flow
rather than changing unrelated event handling.
- Around line 191-204: Update escapedRoot in createPrismaNextClientOptions to
also escape literal { and } characters before constructing the documentSelector
pattern. Keep the existing glob-based pattern and avoid replacing it with
RelativePattern.

In `@packages/vscode/src/util.ts`:
- Around line 124-131: Update restartClient so a rejection from the new client’s
onReady does not prevent returning that client: catch the readiness error,
report it, and return the newly created client while preserving the existing
stop, start, and subscription flow.

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Configuration used: Organization UI

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📥 Commits

Reviewing files that changed from the base of the PR and between bcc6f7e and fc5aeb8.

📒 Files selected for processing (10)

• docs/language-server.md
• packages/vscode/src/plugins/prisma-language-server/documentOwnership.ts
• packages/vscode/src/plugins/prisma-language-server/documentRouting.ts
• packages/vscode/src/plugins/prisma-language-server/index.ts
• packages/vscode/src/plugins/prisma-language-server/languageServerLifecycle.ts
• packages/vscode/src/plugins/prisma-language-server/legacyClientMiddleware.ts
• packages/vscode/src/plugins/prisma-language-server/prismaNextClientMiddleware.ts
• packages/vscode/src/plugins/prisma-language-server/prismaNextClientRegistry.ts
• packages/vscode/src/plugins/prisma-language-server/prismaNextClients.ts
• packages/vscode/src/util.ts

💤 Files with no reviewable changes (6)

• packages/vscode/src/plugins/prisma-language-server/documentRouting.ts
• packages/vscode/src/plugins/prisma-language-server/legacyClientMiddleware.ts
• packages/vscode/src/plugins/prisma-language-server/languageServerLifecycle.ts
• packages/vscode/src/plugins/prisma-language-server/prismaNextClientRegistry.ts
• packages/vscode/src/plugins/prisma-language-server/documentOwnership.ts
• packages/vscode/src/plugins/prisma-language-server/prismaNextClientMiddleware.ts

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