Rewrite candidate_version determination for increased speed, reduced

sensitivity to upstream changes, reduced complexity. Currently Chef
determines this by parsing 'emerge'. This change results in a large
speed increase for Gentoo-based systems.

Reference: https://github.com/chef/chef/issues/7026

Signed-off-by: Gordon Malm <gmalm+github-chef-chef-2018@engineyard.com>

1 files changed, 26 insertions, 32 deletions

diff --git a/lib/chef/provider/package/portage.rb b/lib/chef/provider/package/portage.rb
index e43e71f210..936707911e 100644
--- a/lib/chef/provider/package/portage.rb
+++ b/lib/chef/provider/package/portage.rb
@@ -59,46 +59,40 @@ class Chef
           current_resource
         end
 
-        def parse_emerge(package, txt)
-          availables = {}
-          found_package_name = nil
-
-          txt.each_line do |line|
-            if line =~ /\*\s+#{PACKAGE_NAME_PATTERN}/
-              found_package_name = $&.delete("*").strip
-              if package =~ /\// # the category is specified
-                if found_package_name == package
-                  availables[found_package_name] = nil
-                end
-              else # the category is not specified
-                if found_package_name.split("/").last == package
-                  availables[found_package_name] = nil
-                end
+        def raise_error_for_query(msg)
+          raise Chef::Exceptions::Package, "Query for '#{new_resource.package_name}' #{msg}"
+        end
+
+        def candidate_version
+          return @candidate_version if @candidate_version
+
+          pkginfo = shell_out_compact("portageq", "best_visible", "/", new_resource.package_name)
+
+          if pkginfo.exitstatus != 0
+            pkginfo.stderr.each_line do |line|
+              if line =~ /[Uu]nqualified atom .*match.* multiple/
+                raise_error_for_query("matched multiple packages (please specify a category):\n#{pkginfo.inspect}")
               end
             end
 
-            if line =~ /Latest version available: (.*)/ && availables.key?(found_package_name)
-              availables[found_package_name] = $1.strip
+            if pkginfo.stdout.strip.empty?
+              raise_error_for_query("did not find a matching package:\n#{pkginfo.inspect}")
             end
-          end
 
-          if availables.size > 1
-            # shouldn't happen if a category is specified so just use `package`
-            raise Chef::Exceptions::Package, "Multiple emerge results found for #{package}: #{availables.keys.join(' ')}. Specify a category."
+            raise_error_for_query("resulted in an unknown error:\n#{pkginfo.inspect}")
           end
 
-          availables.values.first
-        end
-
-        def candidate_version
-          return @candidate_version if @candidate_version
-
-          status = shell_out_compact("emerge", "--color", "n", "--nospinner", "--search", new_resource.package_name.split("/").last)
-          available, installed = parse_emerge(new_resource.package_name, status.stdout)
-          @candidate_version = available
+          if pkginfo.stdout.lines.count > 1
+            raise_error_for_query("produced unexpected output (multiple lines):\n#{pkginfo.inspect}")
+          end
 
-          unless status.exitstatus == 0
-            raise Chef::Exceptions::Package, "emerge --search failed - #{status.inspect}!"
+          pkginfo.stdout.chomp!
+          if pkginfo.stdout =~ /-r[[:digit:]]+$/
+            # Latest/Best version of the package is a revision (-rX).
+            @candidate_version = pkginfo.stdout.split(/(?<=-)/).last(2).join
+          else
+            # Latest/Best version of the package is NOT a revision (-rX).
+            @candidate_version = pkginfo.stdout.split('-').last
           end
 
           @candidate_version