Auto merge of #4917 - bundler:seg-settings-temporary, r=indirect

[Settings] Allow temporarily overriding settings in-memory

lib/bundler/cli.rb

@@ -184,11 +184,9 @@ def check
     map "i" => "install"
     def install
       require "bundler/cli/install"
-      no_install = Bundler.settings[:no_install]
-      Bundler.settings[:no_install] = false if no_install == true
-      Install.new(options.dup).run
-    ensure
-      Bundler.settings[:no_install] = no_install unless no_install.nil?
+      Bundler.settings.temporary(:no_install => false) do
+        Install.new(options.dup).run
+      end
     end
 
     desc "update [OPTIONS]", "update the current environment"

lib/bundler/settings.rb

@@ -42,11 +42,18 @@ def initialize(root = nil)
       @local_config    = load_config(local_config_file)
       @global_config   = load_config(global_config_file)
       @cli_flags_given = false
+      @temporary       = {}
     end
 
     def [](name)
       key = key_for(name)
-      value = (@local_config[key] || ENV[key] || @global_config[key] || DEFAULT_CONFIG[name])
+      value = @temporary.fetch(name) do
+              @local_config.fetch(key) do
+              ENV.fetch(key) do
+              @global_config.fetch(key) do
+              DEFAULT_CONFIG.fetch(name) do
+                nil
+              end end end end end
 
       if value.nil?
         nil
@@ -77,6 +84,17 @@ def []=(key, value)
       set_key(key, value, @local_config, local_config_file)
     end
 
+    def temporary(update)
+      existing = Hash[update.map {|k, _| [k, @temporary[k]] }]
+      @temporary.update(update)
+      return unless block_given?
+      begin
+        yield
+      ensure
+        existing.each {|k, v| v.nil? ? @temporary.delete(k) : @temporary[k] = v }
+      end
+    end
+
     alias_method :set_local, :[]=
 
     def delete(key)