swaysw: don't return error when no window is selected in wofi

flake.nix

@@ -4,9 +4,10 @@
   # Nixpkgs / NixOS version to use.
   inputs.nixpkgs.url = "nixpkgs/nixos-unstable";
 
-  outputs = { self, nixpkgs }:
-    let
-
+  outputs = {
+    self,
+    nixpkgs,
+  }: let
     # to work with older version of flakes
     lastModifiedDate = self.lastModifiedDate or self.lastModified or "19700101";
 
@@ -14,58 +15,36 @@
     version = builtins.substring 0 8 lastModifiedDate;
 
     # System types to support.
-      supportedSystems = [ "x86_64-linux" "aarch64-linux" ];
+    supportedSystems = ["x86_64-linux" "aarch64-linux"];
 
     # Helper function to generate an attrset '{ x86_64-linux = f "x86_64-linux"; ... }'.
     forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
 
     # Nixpkgs instantiated for supported system types.
-      nixpkgsFor = forAllSystems (system: import nixpkgs { inherit system; });
-
-    in
-    {
-
+    nixpkgsFor = forAllSystems (system: import nixpkgs {inherit system;});
+  in {
     # Provide some binary packages for selected system types.
-      packages = forAllSystems (system:
-        let
+    packages = forAllSystems (system: let
       pkgs = nixpkgsFor.${system};
-        in
-        {
+    in {
       swaysw = pkgs.buildGoModule {
         pname = "swaysw";
         inherit version;
-            # In 'nix develop', we don't need a copy of the source tree
-            # in the Nix store.
         src = ./.;
-
-            # This hash locks the dependencies of this package. It is
-            # necessary because of how Go requires network access to resolve
-            # VCS.  See https://www.tweag.io/blog/2021-03-04-gomod2nix/ for
-            # details. Normally one can build with a fake sha256 and rely on native Go
-            # mechanisms to tell you what the hash should be or determine what
-            # it should be "out-of-band" with other tooling (eg. gomod2nix).
-            # To begin with it is recommended to set this, but one must
-            # remeber to bump this hash when your dependencies change.
+        ldFlags = ["-s -w"];
         vendorSha256 = null;
 
-            #vendorSha256 = "sha256-pQpattmS9VmO3ZIQUFn66az8GSmB4IvYhTTCFn6SUmo=";
       };
     });
 
-      # Add dependencies that are only needed for development
-      devShells = forAllSystems (system:
-        let 
+    devShells = forAllSystems (system: let
       pkgs = nixpkgsFor.${system};
-        in
-        {
+    in {
       default = pkgs.mkShell {
-            buildInputs = with pkgs; [ go gopls gotools go-tools wofi ];
+        buildInputs = with pkgs; [go gopls gotools go-tools wofi];
       };
     });
 
-      # The default package for 'nix build'. This makes sense if the
-      # flake provides only one package or there is a clear "main"
-      # package.
     defaultPackage = forAllSystems (system: self.packages.${system}.swaysw);
   };
 }

main.go

@@ -44,7 +44,7 @@ func selectWithWofi(windows string) string {
 	cmd.Stdin = strings.NewReader(windows)
 	stdout, err := cmd.Output()
 	if err != nil {
-		log.Fatal(err)
+		return ""
 	}
 	return strings.TrimSpace(string(stdout))
 }
@@ -82,7 +82,8 @@ func main() {
 	var windows []window
 	flatten(swaymsg_output, &windows)
 
-	selected := selectWithWofi(getWindowNames(windows))
+	if selected := selectWithWofi(getWindowNames(windows)); selected != "" {
 		windowId := findWindowId(selected, windows)
 		switchToWindow(windowId)
+	}
 }