Handle Invalid WSL URIs

internal/langserver/handlers/initialize.go

@@ -7,6 +7,7 @@ import (
  "strings"
 
  "github.com/creachadair/jrpc2"
+ "github.com/creachadair/jrpc2/code"
  lsctx "github.com/hashicorp/terraform-ls/internal/context"
  "github.com/hashicorp/terraform-ls/internal/document"
  ilsp "github.com/hashicorp/terraform-ls/internal/lsp"
@@ -132,10 +133,23 @@ func (svc *service) Initialize(ctx context.Context, params lsp.InitializeParams)
  }
  } else {
  rootURI := string(params.RootURI)
+
+ invalidUriErr := jrpc2.Errorf(code.InvalidParams,
+ "Unsupported or invalid URI: %q "+
+ "This is most likely client bug, please report it.", rootURI)
+
+ if uri.IsWSLURI(rootURI) {
+ properties["root_uri"] = "invalid"
+ // For WSL URIs we return additional error data
+ // such that clients (e.g. VS Code) can provide better UX
+ // and nudge users to open in the WSL Remote Extension instead.
+ return serverCaps, invalidUriErr.WithData("INVALID_URI_WSL")
+ }
+
  if !uri.IsURIValid(rootURI) {
  properties["root_uri"] = "invalid"
- return serverCaps, fmt.Errorf("Unsupported or invalid URI: %q "+
-  "This is most likely bug, please report it.", rootURI)
+
+ return serverCaps, invalidUriErr
  }
 
  err := svc.setupWalker(ctx, params, cfgOpts)

internal/langserver/handlers/initialize_test.go

@@ -113,7 +113,7 @@ func TestInitialize_withInvalidRootURI(t *testing.T) {
  "capabilities": {},
  "processId": 12345,
  "rootUri": "meh"
- }`}, code.SystemError.Err())
+ }`}, code.InvalidParams.Err())
 }
 
 func TestInitialize_multipleFolders(t *testing.T) {

internal/uri/uri.go

@@ -185,3 +185,23 @@ func isLikelyWindowsDriveURIPath(uriPath string) bool {
  }
  return uriPath[0] == '/' && unicode.IsLetter(rune(uriPath[1])) && uriPath[2] == ':'
 }
+
+// IsWSLURI checks whether URI represents a WSL (Windows Subsystem for Linux)
+// UNC path on Windows, such as \\wsl$\Ubuntu\path.
+//
+// Such a URI represents a common user error since the LS is generally
+// expected to run in the same environment where files are located
+// (i.e. within the Linux subsystem with Linux paths such as /Ubuntu/path).
+func IsWSLURI(uri string) bool {
+ unescapedPath, err := url.PathUnescape(uri)
+ if err != nil {
+ return false
+ }
+
+ u, err := url.ParseRequestURI(unescapedPath)
+ if err != nil {
+ return false
+ }
+
+ return u.Scheme == "file" && u.Host == "wsl$"
+}

internal/uri/uri_test.go

@@ -178,3 +178,29 @@ func TestMustParseURI(t *testing.T) {
  })
  }
 }
+
+func TestIsWSLURI(t *testing.T) {
+ tests := []struct {
+ name string
+ uri string
+ want bool
+ }{
+ {
+ name: "UNC WSL Path should return true",
+ uri: `file://wsl%24/Ubuntu/home/james/some/path`,
+ want: true,
+ },
+ {
+ name: "Regular file path should return false",
+ uri: `file://C:/foo/james/foo`,
+ want: false,
+ },
+ }
+ for _, tt := range tests {
+ t.Run(tt.name, func(t *testing.T) {
+ if got := IsWSLURI(tt.uri); got != tt.want {
+ t.Errorf("IsWSLURI() = %v, want %v", got, tt.want)
+ }
+ })
+ }
+}