refactor: extract LSP diagnostic report formatter (#21964)

packages/opencode/src/lsp/index.ts

@@ -540,6 +540,8 @@ export namespace LSP {
   export const outgoingCalls = async (input: LocInput) => runPromise((svc) => svc.outgoingCalls(input))
 
   export namespace Diagnostic {
+    const MAX_PER_FILE = 20
+
     export function pretty(diagnostic: LSPClient.Diagnostic) {
       const severityMap = {
         1: "ERROR",
@@ -554,5 +556,14 @@ export namespace LSP {
 
       return `${severity} [${line}:${col}] ${diagnostic.message}`
     }
+
+    export function report(file: string, issues: LSPClient.Diagnostic[]) {
+      const errors = issues.filter((item) => item.severity === 1)
+      if (errors.length === 0) return ""
+      const limited = errors.slice(0, MAX_PER_FILE)
+      const more = errors.length - MAX_PER_FILE
+      const suffix = more > 0 ? `\n... and ${more} more` : ""
+      return `<diagnostics file="${file}">\n${limited.map(pretty).join("\n")}${suffix}\n</diagnostics>`
+    }
   }
 }