PostgreSQL: Treat infinite values in date like datetime consistently

The values infinity and -infinity are supported by both date and
timestamp types.

https://www.postgresql.org/docs/current/static/datatype-datetime.html#DATATYPE-DATETIME-SPECIAL-TABLE

And also, it can not be known whether a value is infinity correctly
unless cast a value.

I've added `QueryAttribute#infinity?` to handle that case.

Closes #27585.

2 files changed, 63 insertions, 0 deletions

diff --git a/activerecord/test/cases/adapters/postgresql/date_test.rb b/activerecord/test/cases/adapters/postgresql/date_test.rb
new file mode 100644
index 0000000000..1562acdcc3
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/date_test.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/topic"
+
+class PostgresqlDateTest < ActiveRecord::PostgreSQLTestCase
+  def test_load_infinity_and_beyond
+    topic = Topic.find_by_sql("SELECT 'infinity'::date AS last_read").first
+    assert topic.last_read.infinite?, "timestamp should be infinite"
+    assert_operator topic.last_read, :>, 0
+
+    topic = Topic.find_by_sql("SELECT '-infinity'::date AS last_read").first
+    assert topic.last_read.infinite?, "timestamp should be infinite"
+    assert_operator topic.last_read, :<, 0
+  end
+
+  def test_save_infinity_and_beyond
+    topic = Topic.create!(last_read: 1.0 / 0.0)
+    assert_equal(1.0 / 0.0, topic.last_read)
+
+    topic = Topic.create!(last_read: -1.0 / 0.0)
+    assert_equal(-1.0 / 0.0, topic.last_read)
+  end
+end
diff --git a/activerecord/test/cases/adapters/postgresql/infinity_test.rb b/activerecord/test/cases/adapters/postgresql/infinity_test.rb
index 0b18c0c9d7..5e56ce8427 100644
--- a/activerecord/test/cases/adapters/postgresql/infinity_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/infinity_test.rb
@@ -13,6 +13,7 @@ class PostgresqlInfinityTest < ActiveRecord::PostgreSQLTestCase
     @connection.create_table(:postgresql_infinities) do |t|
       t.float :float
       t.datetime :datetime
+      t.date :date
     end
   end
 
@@ -43,11 +44,25 @@ class PostgresqlInfinityTest < ActiveRecord::PostgreSQLTestCase
   end
 
   test "type casting infinity on a datetime column" do
+    record = PostgresqlInfinity.create!(datetime: "infinity")
+    record.reload
+    assert_equal Float::INFINITY, record.datetime
+
     record = PostgresqlInfinity.create!(datetime: Float::INFINITY)
     record.reload
     assert_equal Float::INFINITY, record.datetime
   end
 
+  test "type casting infinity on a date column" do
+    record = PostgresqlInfinity.create!(date: "infinity")
+    record.reload
+    assert_equal Float::INFINITY, record.date
+
+    record = PostgresqlInfinity.create!(date: Float::INFINITY)
+    record.reload
+    assert_equal Float::INFINITY, record.date
+  end
+
   test "update_all with infinity on a datetime column" do
     record = PostgresqlInfinity.create!
     PostgresqlInfinity.update_all(datetime: Float::INFINITY)
@@ -68,4 +83,28 @@ class PostgresqlInfinityTest < ActiveRecord::PostgreSQLTestCase
       PostgresqlInfinity.reset_column_information
     end
   end
+
+  test "where clause with infinite range on a datetime column" do
+    record = PostgresqlInfinity.create!(datetime: Time.current)
+
+    string = PostgresqlInfinity.where(datetime: "-infinity".."infinity")
+    assert_equal record, string.take
+
+    infinity = PostgresqlInfinity.where(datetime: -::Float::INFINITY..::Float::INFINITY)
+    assert_equal record, infinity.take
+
+    assert_equal infinity.to_sql, string.to_sql
+  end
+
+  test "where clause with infinite range on a date column" do
+    record = PostgresqlInfinity.create!(date: Date.current)
+
+    string = PostgresqlInfinity.where(date: "-infinity".."infinity")
+    assert_equal record, string.take
+
+    infinity = PostgresqlInfinity.where(date: -::Float::INFINITY..::Float::INFINITY)
+    assert_equal record, infinity.take
+
+    assert_equal infinity.to_sql, string.to_sql
+  end
 end