CHEF-20278: Enhance windows_uuid_from_wmic to use /value flag for reliable UUID retrieval

lib/train/platforms/detect/helpers/os_windows.rb

@@ -146,10 +146,44 @@ def windows_uuid_from_wmic_or_cim
  end
 
  def windows_uuid_from_wmic
- result = @backend.run_command("wmic csproduct get UUID")
+ # Switched from `wmic csproduct get UUID` to `wmic csproduct get UUID /value`
+ # to make the parsing of the UUID more reliable and consistent.
+ #
+ # When using the original `wmic csproduct get UUID` command, the output includes
+ # a header line and spacing that can vary depending on the system, making it harder
+ # to reliably extract the UUID. In some cases, splitting by line and taking the last
+ # element returns an empty string, even when exit_status is 0.
+ #
+ # Example:
+ #
+ # (byebug) result = @backend.run_command("wmic csproduct get UUID")
+ # #<struct Train::Extras::CommandResult stdout="UUID \r\r\nEC20EBD7-8E03-06A8-645F-2D22E5A3BA4B \r\r\n\r\r\n", stderr="", exit_status=0>
+ # (byebug) result.stdout
+ # "UUID \r\r\nEC20EBD7-8E03-06A8-645F-2D22E5A3BA4B \r\r\n\r\r\n"
+ # (byebug) result.exit_status
+ # 0
+ # (byebug) result.stdout.split("\r\n")[-1].strip
+ # ""
+ #
+ # In contrast, `wmic csproduct get UUID /value` returns a consistent `UUID=<value>` format,
+ # which is more suitable for regex matching.
+ #
+ # Example:
+ #
+ # byebug) result = @backend.run_command("wmic csproduct get UUID /value")
+ # #<struct Train::Extras::CommandResult stdout="\r\r\n\r\r\nUUID=EC20EBD7-8E03-06A8-645F-2D22E5A3BA4B\r\r\n\r\r\n\r\r\n\r\r\n", stderr="", exit_status=0>
+ # (byebug) result.stdout
+ # "\r\r\n\r\r\nUUID=EC20EBD7-8E03-06A8-645F-2D22E5A3BA4B\r\r\n\r\r\n\r\r\n\r\r\n"
+ # (byebug) result.stdout&.match(/UUID=([A-F0-9\-]+)/i)&.captures&.first
+ # "EC20EBD7-8E03-06A8-645F-2D22E5A3BA4B"
+ #
+ # This change improves parsing reliability and handles edge cases where the previous
+ # approach would return `nil` or raise errors on empty output lines.
+
+ result = @backend.run_command("wmic csproduct get UUID /value")
  return unless result.exit_status == 0
 
- result.stdout.split("\r\n")[-1].strip
+ result.stdout&.match(/UUID=([A-F0-9\-]+)/i)&.captures&.first
  end
 
  def windows_uuid_from_registry

test/unit/platforms/detect/os_windows_test.rb

@@ -196,3 +196,34 @@ def initialize
  _(detector.platform[:arch]).must_equal("x86_64")
  end
 end
+
+describe "windows_uuid_from_wmic when wmic csproduct get UUID /value returns a valid UUID in stdout" do
+ let(:detector) do
+ detector = OsDetectWindowsTester.new
+ detector.backend.mock_command("wmic csproduct get UUID /value", "\r\r\n\r\r\nUUID=EC20EBD7-8E03-06A8-645F-2D22E5A3BA4B\r\r\n\r\r\n\r\r\n\r\r\n", "", 0)
+ detector
+ end
+
+ it "retrieves the correct UUID from wmic" do
+ _(detector.windows_uuid_from_wmic).must_equal("EC20EBD7-8E03-06A8-645F-2D22E5A3BA4B")
+ end
+end
+
+describe "windows_uuid_from_wmic when stdout is empty even though wmic csproduct get UUID /value exits successfully" do
+
+ # This is a highly unlikely scenario, but there have been cases where customers
+ # observed an empty stdout from `wmic csproduct get UUID` despite a successful exit status.
+ # This test case is to ensure that we handle this gracefully.
+ # In such cases, we should return nil (which is expected) instead of raising an error.
+
+ let(:detector) do
+ detector = OsDetectWindowsTester.new
+ detector.backend.mock_command("wmic csproduct get UUID /value", "", "", 0)
+ detector
+ end
+
+ it "retrieves the correct UUID from wmic" do
+ assert_nil(detector.windows_uuid_from_wmic)
+ end
+end
+

test/unit/platforms/detect/uuid_test.rb

@@ -85,7 +85,7 @@ def mock_platform(name, commands = {}, files = {}, plat_options = {})
  end
 
  it "finds a windows uuid from wmic" do
- commands = { "wmic csproduct get UUID" => "UUID\r\nd400073f-0920-41aa-8dd3-2ea59b18f5ce\r\n", "wmic /?" => "" } # Mocking wmic command to simulate its availability
+ commands = { "wmic csproduct get UUID /value" => "\r\r\n\r\r\nUUID=d400073f-0920-41aa-8dd3-2ea59b18f5ce\r\r\n\r\r\n\r\r\n\r\r\n", "wmic /?" => "" } # Mocking wmic command to simulate its availability
  plat = mock_platform("windows", commands)
  _(plat.uuid).must_equal "d400073f-0920-41aa-8dd3-2ea59b18f5ce"
  end