Make powershell version detection timeout configurable

Allows custom configuration of the powershell timeout and bumps
the default timeout from 10 seconds to 30 seconds.

Fixes #9629

lib/vagrant/util/powershell.rb

@@ -11,6 +11,8 @@ module Vagrant
     class PowerShell
       # NOTE: Version checks are only on Major
       MINIMUM_REQUIRED_VERSION = 3
+      # Number of seconds to wait while attempting to get powershell version
+      DEFAULT_VERSION_DETECTION_TIMEOUT = 30
       LOGGER = Log4r::Logger.new("vagrant::util::powershell")
 
       # @return [String|nil] a powershell executable, depending on environment
@@ -101,8 +103,15 @@ module Vagrant
           ].flatten
 
           version = nil
+          timeout = ENV["VAGRANT_POWERSHELL_VERSION_DETECTION_TIMEOUT"].to_i
+          if timeout < 1
+            timeout = DEFAULT_VERSION_DETECTION_TIMEOUT
+          end
           begin
-            r = Subprocess.execute(*command, notify: [:stdout, :stderr], timeout: 10) {|io_name,data| version = data}
+            r = Subprocess.execute(*command,
+              notify: [:stdout, :stderr],
+              timeout: timeout,
+            ) {|io_name,data| version = data}
           rescue Vagrant::Util::Subprocess::TimeoutExceeded
             LOGGER.debug("Timeout exceeded while attempting to determine version of Powershell.")
           end
@@ -183,6 +192,13 @@ module Vagrant
           Subprocess::Result.new(code, r_stdout, r_stderr)
         end
       end
+
+      # @private
+      # Reset the cached values for platform. This is not considered a public
+      # API and should only be used for testing.
+      def self.reset!
+        instance_variables.each(&method(:remove_instance_variable))
+      end
     end
   end
 end

test/unit/vagrant/util/powershell_test.rb

@@ -0,0 +1,44 @@
+require File.expand_path("../../../base", __FILE__)
+
+require 'vagrant/util/powershell'
+
+describe Vagrant::Util::PowerShell do
+  include_context "unit"
+  describe ".version" do
+    before do
+      allow(described_class).to receive(:executable)
+        .and_return("powershell")
+      allow(Vagrant::Util::Subprocess).to receive(:execute)
+    end
+
+    after do
+      described_class.version
+      described_class.reset!
+    end
+
+    it "should execute powershell command" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with("powershell", any_args)
+    end
+
+    it "should use the default timeout" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with(any_args, hash_including(
+        timeout: Vagrant::Util::PowerShell::DEFAULT_VERSION_DETECTION_TIMEOUT))
+    end
+
+    it "should use environment variable provided timeout" do
+      with_temp_env("VAGRANT_POWERSHELL_VERSION_DETECTION_TIMEOUT" => "1") do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with(any_args, hash_including(
+          timeout: 1))
+        described_class.version
+      end
+    end
+
+    it "should use default timeout when environment variable value is invalid" do
+      with_temp_env("VAGRANT_POWERSHELL_VERSION_DETECTION_TIMEOUT" => "invalid value") do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with(any_args, hash_including(
+          timeout: Vagrant::Util::PowerShell::DEFAULT_VERSION_DETECTION_TIMEOUT))
+        described_class.version
+      end
+    end
+  end
+end