This is a companion to this engines PR:

prisma/prisma-engines#4923

packages/language-server/src/lib/MessageHandler.ts

@@ -53,6 +53,7 @@ import {
 import { prismaSchemaWasmCompletions, localCompletions } from './completions'
 import { PrismaSchema, SchemaDocument } from './Schema'
 import { DiagnosticMap } from './DiagnosticMap'
+import hover from './prisma-schema-wasm/hover'
 
 export function handleDiagnosticsRequest(
   schema: PrismaSchema,
@@ -187,7 +188,14 @@ export function handleHoverRequest(
   schema: PrismaSchema,
   initiatingDocument: TextDocument,
   params: HoverParams,
+  onError?: (errorMessage: string) => void,
 ): Hover | undefined {
+  const hover_res = hover(schema, initiatingDocument, params, onError)
+
+  if (hover_res) {
+    return hover_res
+  }
+
   const position = params.position
 
   const word = getWordAtPosition(initiatingDocument, position)

packages/language-server/src/lib/prisma-schema-wasm/hover.ts

@@ -0,0 +1,31 @@
+import { Hover, HoverParams } from 'vscode-languageserver'
+import { prismaSchemaWasm } from '.'
+import { handleFormatPanic, handleWasmError } from './internals'
+import { PrismaSchema } from '../Schema'
+import { TextDocument } from 'vscode-languageserver-textdocument'
+
+export default function hover(
+  schema: PrismaSchema,
+  initiatingDocument: TextDocument,
+  params: HoverParams,
+  onError?: (errorMessage: string) => void,
+): Hover | undefined {
+  try {
+    if (process.env.FORCE_PANIC_PRISMA_SCHEMA) {
+      handleFormatPanic(() => {
+        console.debug('Triggering a Rust panic...')
+        prismaSchemaWasm.debug_panic()
+      })
+    }
+
+    const result = prismaSchemaWasm.hover(JSON.stringify(schema), JSON.stringify(params))
+
+    return JSON.parse(result) as Hover
+  } catch (e) {
+    const err = e as Error
+
+    handleWasmError(err, 'hover', onError)
+
+    return undefined
+  }
+}

packages/language-server/src/server.ts

@@ -201,7 +201,7 @@ export function startServer(options?: LSOptions): void {
     const doc = getDocument(params.textDocument.uri)
     if (doc) {
       const schema = await PrismaSchema.load(doc, documents)
-      return MessageHandler.handleHoverRequest(schema, doc, params)
+      return MessageHandler.handleHoverRequest(schema, doc, params, showErrorToast)
     }
   })