From 82c1e6fb0ebeb5bb34f03c1ef1b4cd482515f76c Mon Sep 17 00:00:00 2001
From: Markus Reiter <me@reitermark.us>
Date: Mon, 21 Dec 2020 15:43:25 +0100
Subject: [PATCH 1/2] Fix basename for extracting cask downloads.

---
 Library/Homebrew/cask/download.rb  |  4 ++++
 Library/Homebrew/cask/installer.rb | 10 +++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Library/Homebrew/cask/download.rb b/Library/Homebrew/cask/download.rb
index e2f43bf526..30efff34fe 100644
--- a/Library/Homebrew/cask/download.rb
+++ b/Library/Homebrew/cask/download.rb
@@ -52,6 +52,10 @@ module Cask
       downloader.cached_location
     end
 
+    def basename
+      downloader.basename
+    end
+
     def verify_download_integrity(fn)
       if @cask.sha256 == :no_check
         opoo "No checksum defined for cask '#{@cask}', skipping verification."
diff --git a/Library/Homebrew/cask/installer.rb b/Library/Homebrew/cask/installer.rb
index a3cf058dec..318cb045ba 100644
--- a/Library/Homebrew/cask/installer.rb
+++ b/Library/Homebrew/cask/installer.rb
@@ -152,10 +152,14 @@ module Cask
       s.freeze
     end
 
+    sig { returns(Download) }
+    def downloader
+      @downloader ||= Download.new(@cask, quarantine: quarantine?)
+    end
+
     sig { returns(Pathname) }
     def download
-      @download ||= Download.new(@cask, quarantine: quarantine?)
-                            .fetch(verify_download_integrity: @verify_download_integrity)
+      @download ||= downloader.fetch(verify_download_integrity: @verify_download_integrity)
     end
 
     def verify_has_sha
@@ -180,7 +184,7 @@ module Cask
 
       odebug "Using container class #{primary_container.class} for #{primary_container.path}"
 
-      basename = CGI.unescape(File.basename(@cask.url.path))
+      basename = downloader.basename
 
       if nested_container = @cask.container&.nested
         Dir.mktmpdir do |tmpdir|

From 8b17017108d5b550562b556c5d407361cea27781 Mon Sep 17 00:00:00 2001
From: Markus Reiter <me@reitermark.us>
Date: Mon, 21 Dec 2020 15:45:18 +0100
Subject: [PATCH 2/2] Improve error message for missing PKG source.

---
 Library/Homebrew/cask/artifact/pkg.rb | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/cask/artifact/pkg.rb b/Library/Homebrew/cask/artifact/pkg.rb
index ae717a3e7e..f6eef1e42c 100644
--- a/Library/Homebrew/cask/artifact/pkg.rb
+++ b/Library/Homebrew/cask/artifact/pkg.rb
@@ -42,7 +42,14 @@ module Cask
         ohai "Running installer for #{cask}; your password may be necessary."
         ohai "Package installers may write to any location; options such as --appdir are ignored."
         unless path.exist?
-          raise CaskError, "pkg source file not found: '#{path.relative_path_from(cask.staged_path)}'"
+          pkg = path.relative_path_from(cask.staged_path)
+          pkgs = Pathname.glob(cask.staged_path/"**"/"*.pkg").map { |path| path.relative_path_from(cask.staged_path) }
+
+          message = "Could not find PKG source file '#{pkg}'"
+          message += ", found #{pkgs.map { |path| "'#{path}'" }.to_sentence} instead" if pkgs.any?
+          message += "."
+
+          raise CaskError, message
         end
 
         args = [