Using table name qualified column names unless having SELECT list explicitly

Previously table name qualified `*` is used in that case. If it is not
qualified with a table name, an ambiguous column name error will occur
when using JOINs.

2 files changed, 9 insertions, 5 deletions

diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 6b3ff3d610..2056f9bb73 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -1040,8 +1040,8 @@ module ActiveRecord
       def build_select(arel)
         if select_values.any?
           arel.project(*arel_columns(select_values.uniq))
-        elsif @klass.ignored_columns.any?
-          arel.project(*arel_columns(@klass.column_names.map(&:to_sym)))
+        elsif klass.ignored_columns.any?
+          arel.project(*klass.column_names.map { |field| arel_attribute(field) })
         else
           arel.project(table[Arel.star])
         end
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 7fc4a396e4..b076b452e7 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1498,10 +1498,14 @@ class BasicsTest < ActiveRecord::TestCase
 
   test "column names are quoted when using #from clause and model has ignored columns" do
     refute_empty Developer.ignored_columns
-    query = Developer.from("`developers`").to_sql
-    quoted_id = Developer.connection.quote_table_name("id")
+    query = Developer.from("developers").to_sql
+    quoted_id = "#{Developer.quoted_table_name}.#{Developer.quoted_primary_key}"
 
-    assert_match(/SELECT #{quoted_id}.* FROM `developers`/, query)
+    assert_match(/SELECT #{quoted_id}.* FROM developers/, query)
+  end
+
+  test "using table name qualified column names unless having SELECT list explicitly" do
+    assert_equal developers(:david), Developer.from("developers").joins(:shared_computers).take
   end
 
   test "protected environments by default is an array with production" do