From 83aa3f8cd5d83c147e6e9097241e0365c6b14ec2 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 20 Aug 2026 20:25:21 +0000
Subject: [PATCH 1/2] Initial plan


From a67ce0b664adc08d9ca68d190dc219122390a502 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 20 Aug 2026 20:34:29 +0000
Subject: [PATCH 2/2] Add first-open pull diagnostics regression test

Co-authored-by: RyanCavanaugh <6685088+RyanCavanaugh@users.noreply.github.com>
---
 tsc/internal/lsp/server_diagnostics_test.go | 74 +++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 tsc/internal/lsp/server_diagnostics_test.go

diff --git a/tsc/internal/lsp/server_diagnostics_test.go b/tsc/internal/lsp/server_diagnostics_test.go
new file mode 100644
index 0000000000000..9e59b3c2da409
--- /dev/null
+++ b/tsc/internal/lsp/server_diagnostics_test.go
@@ -0,0 +1,74 @@
+package lsp_test
+
+import (
+	"context"
+	"io"
+	"testing"
+
+	"github.com/microsoft/TypeScript/tsc/internal/bundled"
+	"github.com/microsoft/TypeScript/tsc/internal/lsp"
+	"github.com/microsoft/TypeScript/tsc/internal/lsp/lsproto"
+	"github.com/microsoft/TypeScript/tsc/internal/testutil/lsptestutil"
+	"github.com/microsoft/TypeScript/tsc/internal/vfs/vfstest"
+	"gotest.tools/v3/assert"
+)
+
+func TestDiagnosticsForFirstOpenedFile(t *testing.T) {
+	t.Parallel()
+	if !bundled.Embedded {
+		t.Skip("bundled files are not embedded")
+	}
+
+	const broken = `import { greet } from "./helper";
+export const message = greet("world");
+const bad: string = 123;`
+	fs := bundled.WrapFS(vfstest.FromMap(map[string]string{
+		"/home/project/tsconfig.json": `{"compilerOptions":{"target":"es2020","module":"esnext","moduleResolution":"bundler","strict":true,"noEmit":true},"include":["*.ts"]}`,
+		"/home/project/helper.ts":     "export function greet(name: string): string { return `Hello, ${name}`; }",
+		"/home/project/broken.ts":     broken,
+	}, false))
+	onServerRequest := func(_ context.Context, req *lsproto.RequestMessage) *lsproto.ResponseMessage {
+		switch req.Method {
+		case lsproto.MethodWorkspaceConfiguration:
+			return &lsproto.ResponseMessage{ID: req.ID, JSONRPC: req.JSONRPC, Result: []any{nil, nil, nil, nil}}
+		case lsproto.MethodClientRegisterCapability, lsproto.MethodClientUnregisterCapability:
+			return &lsproto.ResponseMessage{ID: req.ID, JSONRPC: req.JSONRPC, Result: lsproto.Null{}}
+		default:
+			return nil
+		}
+	}
+	client, closeClient := lsptestutil.NewLSPClient(t, lsp.ServerOptions{
+		Err:                io.Discard,
+		Cwd:                "/home/project",
+		FS:                 fs,
+		DefaultLibraryPath: bundled.LibPath(),
+	}, onServerRequest)
+	t.Cleanup(func() { _ = closeClient() })
+
+	initMsg, _, ok := lsptestutil.SendRequest(t, client, lsproto.InitializeInfo, &lsproto.InitializeParams{
+		Capabilities: &lsproto.ClientCapabilities{
+			TextDocument: &lsproto.TextDocumentClientCapabilities{
+				Diagnostic: &lsproto.DiagnosticClientCapabilities{},
+			},
+		},
+	})
+	assert.Assert(t, ok && initMsg.AsResponse().Error == nil, "initialize failed")
+	lsptestutil.SendNotification(t, client, lsproto.InitializedInfo, &lsproto.InitializedParams{})
+	<-client.Server.InitComplete()
+
+	uri := lsproto.DocumentUri("file:///home/project/broken.ts")
+	lsptestutil.SendNotification(t, client, lsproto.TextDocumentDidOpenInfo, &lsproto.DidOpenTextDocumentParams{
+		TextDocument: &lsproto.TextDocumentItem{Uri: uri, LanguageId: "typescript", Version: 1, Text: broken},
+	})
+	diagnosticMsg, diagnostics, ok := lsptestutil.SendRequest(t, client, lsproto.TextDocumentDiagnosticInfo, &lsproto.DocumentDiagnosticParams{
+		TextDocument: lsproto.TextDocumentIdentifier{Uri: uri},
+	})
+	assert.Assert(t, ok && diagnosticMsg.AsResponse().Error == nil)
+	assert.Assert(t, diagnostics.FullDocumentDiagnosticReport != nil)
+	for _, diagnostic := range diagnostics.FullDocumentDiagnosticReport.Items {
+		if diagnostic.Code != nil && diagnostic.Code.Integer != nil && *diagnostic.Code.Integer == 2322 {
+			return
+		}
+	}
+	t.Fatalf("diagnostics did not contain TS2322: %v", diagnostics.FullDocumentDiagnosticReport.Items)
+}