Support strict enforcement of internal dependency constraints

lib/vagrant/bundler.rb

@@ -215,7 +215,11 @@ module Vagrant
       update = {} if !update.is_a?(Hash)
       skips = []
       source_list = {}
+      system_plugins = plugins.map do |plugin_name, plugin_info|
+        plugin_name if plugin_info["system"]
+      end.compact
       installer_set = VagrantSet.new(:both)
+      installer_set.system_plugins = system_plugins
 
       # Generate all required plugin deps
       plugin_deps = plugins.map do |name, info|
@@ -239,7 +243,18 @@ module Vagrant
         Gem::Dependency.new(name, gem_version)
       end
 
-      @logger.debug("Dependency list for installation: #{plugin_deps}")
+      if Vagrant.strict_dependency_enforcement
+        @logger.debug("Enabling strict dependency enforcement")
+        plugin_deps += vagrant_internal_specs.map do |spec|
+          next if system_plugins.include?(spec.name)
+          Gem::Dependency.new(spec.name, spec.version)
+        end.compact
+      else
+        @logger.debug("Disabling strict dependency enforcement")
+      end
+
+      @logger.debug("Dependency list for installation:\n - " \
+        "#{plugin_deps.map{|d| "#{d.name} #{d.requirement}"}.join("\n - ")}")
 
       all_sources = source_list.values.flatten.uniq
       default_sources = DEFAULT_GEM_SOURCES & all_sources
@@ -275,11 +290,6 @@ module Vagrant
       # Create the request set for the new plugins
       request_set = Gem::RequestSet.new(*plugin_deps)
 
-      system_plugins = plugins.map do |plugin_name, plugin_info|
-        plugin_name if plugin_info["system"]
-      end.compact
-      installer_set.system_plugins = system_plugins
-
       installer_set = Gem::Resolver.compose_sets(
         installer_set,
         generate_builtin_set(system_plugins),

lib/vagrant/shared_helpers.rb

@@ -116,4 +116,17 @@ module Vagrant
   def self.prerelease?
     Gem::Version.new(Vagrant::VERSION).prerelease?
   end
+
+  # This allows control over dependency resolution when installing
+  # plugins into vagrant. When true, dependency libraries that Vagrant
+  # core relies upon will be hard constraints.
+  #
+  # @return [Boolean]
+  def self.strict_dependency_enforcement
+    if ENV["VAGRANT_DISABLE_STRICT_DEPENDENCY_ENFORCEMENT"]
+      false
+    else
+      true
+    end
+  end
 end