Bypass string_agg on jruby until jdbc-sqlite3 supports it

lib/gemstash/compact_index_builder.rb

@@ -181,6 +181,8 @@ def build_result
     private
 
       def requirements_and_dependencies
+        return requirements_and_dependencies_without_string_agg if RUBY_PLATFORM == "java"
+
         DB::Rubygem.association_left_join(versions: :dependencies).
           where(name: @name).
           where { versions[:indexed] }.
@@ -214,6 +216,40 @@ def requirements_and_dependencies
         end
       end
 
+      def requirements_and_dependencies_without_string_agg
+        results = DB::Rubygem.
+                  association_left_join(:versions).
+                  where(name: @name).
+                  where { versions[:indexed] }.
+                  order { [versions[:created_at], versions[:number], versions[:platform]] }.
+                  select do
+          [versions[:id].as(:version_id), versions[:number], versions[:platform], versions[:sha256], versions[:info_checksum], versions[:required_ruby_version], versions[:required_rubygems_version], versions[:created_at]]
+        end
+
+        version_ids = results.map {|v| v[:version_id] }
+
+        # Without string_agg this is less efficient. Waiting for jdbc-sqlite3 to support string_agg
+        deps = DB::Dependency.
+               where(version_id: version_ids).
+               select(:version_id, :rubygem_name, :requirements).
+               each_with_object({}) do |dep, agg|
+          agg[dep.version_id] ||= []
+          agg[dep.version_id] << CompactIndex::Dependency.new(dep.rubygem_name, dep.requirements)
+        end
+
+        results.map do |row|
+          CompactIndex::GemVersion.new(
+            row[:number],
+            row[:platform],
+            row[:sha256],
+            nil, # info_checksum
+            deps[row[:version_id]] || [],
+            row[:required_ruby_version],
+            row[:required_rubygems_version]
+          )
+        end
+      end
+
       def key
         :info
       end

lib/gemstash/db.rb

@@ -11,7 +11,7 @@ module DB
     Sequel::Model.raise_on_save_failure = true
     Sequel::Model.plugin :timestamps, update_on_create: true
     Sequel::Model.db.extension :error_sql
-    Sequel::Model.db.extension :string_agg
+    Sequel::Model.db.extension :string_agg if RUBY_PLATFORM != "java"
     Sequel::Model.db.extension :schema_dumper
     autoload :Authorization, "gemstash/db/authorization"
     autoload :CachedRubygem, "gemstash/db/cached_rubygem"