Reject non-dictionary stringsdict entries with a clear error

`read` checked only that the plist root is a dictionary, so a file whose
entry value wasn't a dictionary (e.g. a key mapped to a string) slipped
through and crashed later in `plural_variables` with a cryptic
`NoMethodError: private method 'select' called for String`. Validate each
entry up front and raise the same clean `UI.user_error!` the root check
uses, naming the offending key.

Author: jkmassel

lib/fastlane/plugin/wpmreleasetoolkit/helper/ios/ios_stringsdict_helper.rb

@@ -55,13 +55,18 @@ class StringsdictHelper
         #
         # @param [String] path The path to the `.stringsdict` file.
         # @return [Hash] The parsed plist dictionary.
-        # @raise [FastlaneCore::Interface::FastlaneError] If the file is missing or is not a plist dictionary.
+        # @raise [FastlaneCore::Interface::FastlaneError] If the file is missing, is not a plist
+        #   dictionary, or contains an entry whose value is not a dictionary.
         def self.read(path:)
           UI.user_error!("Stringsdict file not found: #{path}") unless File.exist?(path)
 
           data = Plist.parse_xml(path)
           UI.user_error!("Invalid stringsdict file (expected a plist dictionary at the root): #{path}") unless data.is_a?(Hash)
 
+          data.each do |key, value|
+            UI.user_error!("Invalid stringsdict file (entry '#{key}' is not a dictionary): #{path}") unless value.is_a?(Hash)
+          end
+
           data
         end
 

spec/ios_stringsdict_helper_spec.rb

@@ -53,6 +53,19 @@ def convert_po_to_stringsdict(po_content, template:, locale:)
       expect { described_class.read(path: 'does-not-exist.stringsdict') }
         .to raise_error(FastlaneCore::Interface::FastlaneError, /Stringsdict file not found/)
     end
+
+    it 'raises a clear error when an entry is not a dictionary' do
+      in_tmp_dir do |dir|
+        bad = File.join(dir, 'bad.stringsdict')
+        File.write(bad, <<~XML)
+          <?xml version="1.0" encoding="UTF-8"?>
+          <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+          <plist version="1.0"><dict><key>oops</key><string>not a dictionary</string></dict></plist>
+        XML
+        expect { described_class.read(path: bad) }
+          .to raise_error(FastlaneCore::Interface::FastlaneError, /entry 'oops' is not a dictionary/)
+      end
+    end
   end
 
   describe 'round-trip write/read' do