Upgrading Flutter Beta Channel

Help
1

I copied the first flake.nix from https://nixos.wiki/wiki/Flutter, and everything works fine when I run nix develop
But I need to switch to the beta channel, so when I run flutter channel beta I get the error

Switching to flutter channel ‘beta’…
Switching channels failed
fatal: detected dubious ownership in repository at
‘/nix/store/nir2w2fd8xj3i45gmqbbqbcm4kivf1j4-flutter-wrapped-3.27.1-sdk-links’
To add an exception for this directory, call:

    git config --global --add safe.directory
    /nix/store/nir2w2fd8xj3i45gmqbbqbcm4kivf1j4-flutter-wrapped-3.27.1-sdk-links.

Running git config --global --add safe.directory /nix/store/nir2w2fd8xj3i45gmqbbqbcm4kivf1j4-flutter-wrapped-3.27.1-sdk-links
and then flutter run upgrade again, I get the error

Switching to flutter channel ‘beta’…
Switching channels failed
error: cannot open ‘.git/FETCH_HEAD’: Read-only file system.

I see flutterPackages-source.beta exists in the nixpkgs, but I’m not sure how to use it.
Any help for upgrading to the flutter beta channel would be appreciated.

2

Here is my flake.nix

{
description = "Flutter 3.27.x";
inputs = {
  nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
  flake-utils.url = "github:numtide/flake-utils";
};
outputs = { self, nixpkgs, flake-utils }:
  flake-utils.lib.eachDefaultSystem (system:
    let
      pkgs = import nixpkgs {
        inherit system;
        config = {
          android_sdk.accept_license = true;
          allowUnfree = true;
        };
      };
      buildToolsVersion = "34.0.0";
      androidComposition = pkgs.androidenv.composeAndroidPackages {
        buildToolsVersions = [ buildToolsVersion "28.0.3" ];
        platformVersions = [ "34" "28" ];
        abiVersions = [ "armeabi-v7a" "arm64-v8a" ];
      };
      androidSdk = androidComposition.androidsdk;
    in
    {
      devShell =
        with pkgs; mkShell {
          ANDROID_SDK_ROOT = "${androidSdk}/libexec/android-sdk";
          buildInputs = [
            flutter
            flutterPackages-source.beta
            androidSdk # The customized SDK that we've made above
            jdk17
          ];
	     shellHook = ''
	        zsh
   	      '';
        };
    });
}
4

I get the same git error when I use buildFSHEnv

{
	description = "Flutter 3.27.x";
	inputs = {
		nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
		flake-utils.url = "github:numtide/flake-utils";
	};
	outputs = { self, nixpkgs, flake-utils }:
		flake-utils.lib.eachDefaultSystem (system:
			let
				pkgs = import nixpkgs {
					inherit system;
					config = {
						android_sdk.accept_license = true;
						allowUnfree = true;
					};
				};
				buildToolsVersion = "34.0.0";
				androidComposition = pkgs.androidenv.composeAndroidPackages {
					buildToolsVersions = [ buildToolsVersion "28.0.3" ];
					platformVersions = [ "34" "28" ];
					abiVersions = [ "armeabi-v7a" "arm64-v8a" ];
				};
				androidSdk = androidComposition.androidsdk;
			in
				{

				devShell = 
					(pkgs.buildFHSEnv {
						name = "flutter beta";
						targetPkgs = pkgs:
							[ pkgs.flutter androidSdk pkgs.jdk17 ];
						runScript = ''
		zsh
		export ANDROID_SDK_ROOT = "${androidSdk}/libexec/android-sdk";
						'';
					}).env;
			});
}