cask uninstall script: allow tilde expansion to '$HOME'

Library/Homebrew/cask/artifact/abstract_artifact.rb

@@ -30,6 +30,7 @@ module Cask
 
       def staged_path_join_executable(path)
         path = Pathname(path)
+        path = path.expand_path if path.to_s.start_with?("~")
 
         absolute_path = if path.absolute?
           path

Library/Homebrew/test/cask/cmd/uninstall_spec.rb

@@ -90,6 +90,30 @@ describe Cask::Cmd::Uninstall, :cask do
     expect(cask).not_to be_installed
   end
 
+  context "when Casks use script path with `~` as `HOME`" do
+    let(:home_dir) { mktmpdir }
+    let(:app) { Pathname.new("#{home_dir}/MyFancyApp.app") }
+    let(:cask) { Cask::CaskLoader.load(cask_path("with-uninstall-script-user-relative")) }
+
+    before do
+      ENV["HOME"] = home_dir
+    end
+
+    it "can still uninstall them" do
+      Cask::Installer.new(cask).install
+
+      expect(cask).to be_installed
+      expect(app).to exist
+
+      expect {
+        described_class.run("with-uninstall-script-user-relative")
+      }.not_to raise_error
+
+      expect(cask).not_to be_installed
+      expect(app).not_to exist
+    end
+  end
+
   describe "when multiple versions of a cask are installed" do
     let(:token) { "versioned-cask" }
     let(:first_installed_version) { "1.2.3" }

Library/Homebrew/test/support/fixtures/cask/Casks/with-uninstall-script-user-relative.rb

@@ -0,0 +1,21 @@
+cask "with-uninstall-script-user-relative" do
+  version "1.2.3"
+  sha256 "5633c3a0f2e572cbf021507dec78c50998b398c343232bdfc7e26221d0a5db4d"
+
+  url "file://#{TEST_FIXTURE_DIR}/cask/MyFancyApp.zip"
+  homepage "https://brew.sh/MyFancyApp"
+
+  app "MyFancyApp/MyFancyApp.app", target: "~/MyFancyApp.app"
+
+  postflight do
+    IO.write "#{ENV["HOME"]}/MyFancyApp.app/uninstall.sh", <<~SH
+      #!/bin/sh
+      /bin/rm -r "#{ENV["HOME"]}/MyFancyApp.app"
+    SH
+  end
+
+  uninstall script: {
+    executable: "~/MyFancyApp.app/uninstall.sh",
+    sudo:       false,
+  }
+end