Fix LSP formatting that broke in v0.26.0 (#1055)

Fixes #1054

Signed-off-by: Anders Eknert <anders@styra.com>

internal/lsp/server.go

@@ -1799,7 +1799,12 @@ func (l *LanguageServer) handleTextDocumentFormatting(
 		f := &fixes.Fmt{OPAFmtOpts: opts}
 		p := uri.ToPath(l.clientIdentifier, params.TextDocument.URI)
 
-		fixResults, err := f.Fix(&fixes.FixCandidate{Filename: filepath.Base(p), Contents: []byte(oldContent)}, nil)
+		fixResults, err := f.Fix(
+			&fixes.FixCandidate{Filename: filepath.Base(p), Contents: []byte(oldContent)},
+			&fixes.RuntimeOptions{
+				BaseDir: l.workspacePath(),
+			},
+		)
 		if err != nil {
 			l.logError(fmt.Errorf("failed to format file: %w", err))
 

internal/lsp/server_test.go

@@ -3,6 +3,7 @@ package lsp
 import (
 	"bytes"
 	"context"
+	"encoding/json"
 	"fmt"
 	"io"
 	"net"
@@ -731,6 +732,91 @@ func TestProcessBuiltinUpdateExitsOnMissingFile(t *testing.T) {
 	}
 }
 
+func TestFormatting(t *testing.T) {
+	t.Parallel()
+
+	tempDir := t.TempDir()
+
+	// set up the server and client connections
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	ls := NewLanguageServer(&LanguageServerOptions{
+		ErrorLog: newTestLogger(t),
+	})
+	go ls.StartConfigWorker(ctx)
+
+	clientHandler := func(_ context.Context, _ *jsonrpc2.Conn, req *jsonrpc2.Request) (result any, err error) {
+		t.Fatalf("unexpected request: %v", req)
+
+		return struct{}{}, nil
+	}
+
+	connServer, connClient, cleanup := createConnections(ctx, ls.Handle, clientHandler)
+	defer cleanup()
+
+	ls.SetConn(connServer)
+
+	// 1. Client sends initialize request
+	request := types.InitializeParams{
+		RootURI:    fileURIScheme + tempDir,
+		ClientInfo: types.Client{Name: "go test"},
+	}
+
+	var response types.InitializeResult
+
+	err := connClient.Call(ctx, "initialize", request, &response)
+	if err != nil {
+		t.Fatalf("failed to send initialize request: %s", err)
+	}
+
+	mainRegoURI := fileURIScheme + tempDir + mainRegoFileName
+
+	// Simple as possible — opa fmt should just remove a newline
+	content := `package main
+
+`
+	ls.cache.SetFileContents(mainRegoURI, content)
+
+	bs, err := json.Marshal(&types.DocumentFormattingParams{
+		TextDocument: types.TextDocumentIdentifier{URI: mainRegoURI},
+		Options:      types.FormattingOptions{},
+	})
+	if err != nil {
+		t.Fatalf("failed to marshal document formatting params: %v", err)
+	}
+
+	var msg json.RawMessage = bs
+
+	req := &jsonrpc2.Request{Params: &msg}
+
+	res, err := ls.handleTextDocumentFormatting(ctx, connClient, req)
+	if err != nil {
+		t.Fatalf("failed to format document: %s", err)
+	}
+
+	if edits, ok := res.([]types.TextEdit); ok {
+		if len(edits) != 1 {
+			t.Fatalf("expected 1 edit, got %d", len(edits))
+		}
+
+		expectRange := types.Range{
+			Start: types.Position{Line: 1, Character: 0},
+			End:   types.Position{Line: 2, Character: 0},
+		}
+
+		if edits[0].Range != expectRange {
+			t.Fatalf("expected range to be %v, got %v", expectRange, edits[0].Range)
+		}
+
+		if edits[0].NewText != "" {
+			t.Fatalf("expected new text to be empty, got %s", edits[0].NewText)
+		}
+	} else {
+		t.Fatalf("expected edits to be []types.TextEdit, got %T", res)
+	}
+}
+
 // TestLanguageServerParentDirConfig tests that regal config is loaded as it is for the
 // Regal CLI, and that config files in a parent directory are loaded correctly
 // even when the workspace is a child directory.