Correctly handle infinity value in PostgreSQL range type

An empty string is an invalid value in Ruby's range class.
So need to handle `Float::INFINITY` as it is and cast it in
`encode_range`.

Fixes #31612

2 files changed, 10 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
index a89aa5ea09..6edb7cfd3c 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
@@ -60,7 +60,7 @@ module ActiveRecord
             end
 
             def type_cast_single_for_database(value)
-              infinity?(value) ? "" : @subtype.serialize(value)
+              infinity?(value) ? value : @subtype.serialize(value)
             end
 
             def extract_bounds(value)
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
index 9fdeab06c1..e75202b0be 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
@@ -138,7 +138,7 @@ module ActiveRecord
           end
 
           def encode_range(range)
-            "[#{type_cast(range.first)},#{type_cast(range.last)}#{range.exclude_end? ? ')' : ']'}"
+            "[#{type_cast_range_value(range.first)},#{type_cast_range_value(range.last)}#{range.exclude_end? ? ')' : ']'}"
           end
 
           def determine_encoding_of_strings_in_array(value)
@@ -154,6 +154,14 @@ module ActiveRecord
             else _type_cast(values)
             end
           end
+
+          def type_cast_range_value(value)
+            infinity?(value) ? "" : type_cast(value)
+          end
+
+          def infinity?(value)
+            value.respond_to?(:infinite?) && value.infinite?
+          end
       end
     end
   end