add --allow-downgrades to apt-get

Signed-off-by: Lamont Granquist <lamont@scriptkiddie.org>

2 files changed, 20 insertions, 8 deletions

diff --git a/lib/chef/provider/package/apt.rb b/lib/chef/provider/package/apt.rb
index bfb24e502d..de1b106d45 100644
--- a/lib/chef/provider/package/apt.rb
+++ b/lib/chef/provider/package/apt.rb
@@ -1,6 +1,6 @@
 #
 # Author:: Adam Jacob (<adam@chef.io>)
-# Copyright:: Copyright 2008-2017, Chef Software Inc.
+# Copyright:: Copyright 2008-2018, Chef Software Inc.
 # License:: Apache License, Version 2.0
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -92,7 +92,8 @@ class Chef
           package_name = name.zip(version).map do |n, v|
             package_data[n][:virtual] ? n : "#{n}=#{v}"
           end
-          run_noninteractive("apt-get", "-q", "-y", config_file_options, default_release_options, options, "install", package_name)
+          dgrade = "--allow-downgrades" if supports_allow_downgrade? && allow_downgrade
+          run_noninteractive("apt-get", "-q", "-y", dgrade, config_file_options, default_release_options, options, "install", package_name)
         end
 
         def upgrade_package(name, version)
@@ -133,6 +134,17 @@ class Chef
 
         private
 
+        # @return [String] version of apt-get which is installed
+        def apt_version
+          @apt_version ||= shell_out("apt-get --version").stdout.match(/^apt (\S+)/)[1]
+        end
+
+        # @return [Boolean] if apt-get supports --allow-downgrades
+        def supports_allow_downgrade?
+          return @supports_allow_downgrade unless @supports_allow_downgrade.nil?
+          @supports_allow_downgrade = ( version_compare(apt_version, "1.1.0") >= 0 )
+        end
+
         # compare 2 versions to each other to see which is newer.
         # this differs from the standard package method because we
         # need to be able to parse debian version strings which contain
diff --git a/spec/unit/provider/package/apt_spec.rb b/spec/unit/provider/package/apt_spec.rb
index 05be08f332..7df1a8f3a6 100644
--- a/spec/unit/provider/package/apt_spec.rb
+++ b/spec/unit/provider/package/apt_spec.rb
@@ -259,7 +259,7 @@ describe Chef::Provider::Package::Apt do
     describe "install_package" do
       it "should run apt-get install with the package name and version" do
         expect(@provider).to receive(:shell_out_compacted!). with(
-          "apt-get", "-q", "-y", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "install", "irssi=0.8.12-7",
+          "apt-get", "-q", "-y", "--allow-downgrades", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "install", "irssi=0.8.12-7",
           env: { "DEBIAN_FRONTEND" => "noninteractive" },
           timeout: @timeout
         )
@@ -268,7 +268,7 @@ describe Chef::Provider::Package::Apt do
 
       it "should run apt-get install with the package name and version and options if specified" do
         expect(@provider).to receive(:shell_out_compacted!).with(
-          "apt-get", "-q", "-y", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "--force-yes", "install", "irssi=0.8.12-7",
+          "apt-get", "-q", "-y", "--allow-downgrades", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "--force-yes", "install", "irssi=0.8.12-7",
           env: { "DEBIAN_FRONTEND" => "noninteractive" },
           timeout: @timeout
         )
@@ -284,7 +284,7 @@ describe Chef::Provider::Package::Apt do
         @provider.new_resource = @new_resource
 
         expect(@provider).to receive(:shell_out_compacted!).with(
-          "apt-get", "-q", "-y", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "-o", "APT::Default-Release=lenny-backports", "install", "irssi=0.8.12-7",
+          "apt-get", "-q", "-y", "--allow-downgrades", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "-o", "APT::Default-Release=lenny-backports", "install", "irssi=0.8.12-7",
           env: { "DEBIAN_FRONTEND" => "noninteractive" },
           timeout: @timeout
         )
@@ -294,7 +294,7 @@ describe Chef::Provider::Package::Apt do
 
       it "should run apt-get install with the package name and quotes options if specified" do
         expect(@provider).to receive(:shell_out_compacted!).with(
-          "apt-get", "-q", "-y", "--force-yes", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confnew", "install", "irssi=0.8.12-7",
+          "apt-get", "-q", "-y", "--allow-downgrades", "--force-yes", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confnew", "install", "irssi=0.8.12-7",
           env: { "DEBIAN_FRONTEND" => "noninteractive" },
           timeout: @timeout
         )
@@ -451,7 +451,7 @@ describe Chef::Provider::Package::Apt do
       it "should install the package without specifying a version" do
         @provider.package_data["libmysqlclient15-dev"][:virtual] = true
         expect(@provider).to receive(:shell_out_compacted!).with(
-          "apt-get", "-q", "-y", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "install", "libmysqlclient15-dev",
+          "apt-get", "-q", "-y", "--allow-downgrades", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "install", "libmysqlclient15-dev",
           env: { "DEBIAN_FRONTEND" => "noninteractive" },
           timeout: @timeout
         )
@@ -487,7 +487,7 @@ describe Chef::Provider::Package::Apt do
       it "can install a virtual package followed by a non-virtual package" do
         # https://github.com/chef/chef/issues/2914
         expect(@provider).to receive(:shell_out_compacted!).with(
-          "apt-get", "-q", "-y", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "install", "libmysqlclient15-dev", "irssi=0.8.12-7",
+          "apt-get", "-q", "-y", "--allow-downgrades", "-o", "Dpkg::Options::=--force-confdef", "-o", "Dpkg::Options::=--force-confold", "install", "libmysqlclient15-dev", "irssi=0.8.12-7",
           env: { "DEBIAN_FRONTEND" => "noninteractive" },
           timeout: @timeout
         )