Correctly respect subtypes for PG arrays and ranges

The type registration was simply looking for the OID, and eagerly
fetching/constructing the sub type when it was registered. However,
numeric types have additional parameters which are extracted from the
actual SQL string of the type during lookup, and can have their behavior
change based on the result.

We simply need to use the block form of registration, and look up the
subtype lazily instead.

Fixes #17935

2 files changed, 25 insertions, 10 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
index 35e699eeda..9b3de41fab 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
@@ -39,14 +39,14 @@ module ActiveRecord
           end
 
           def register_array_type(row)
-            if subtype = @store.lookup(row['typelem'].to_i)
-              register row['oid'], OID::Array.new(subtype, row['typdelim'])
+            register_with_subtype(row['oid'], row['typelem'].to_i) do |subtype|
+              OID::Array.new(subtype, row['typdelim'])
             end
           end
 
           def register_range_type(row)
-            if subtype = @store.lookup(row['rngsubtype'].to_i)
-              register row['oid'], OID::Range.new(subtype, row['typname'].to_sym)
+            register_with_subtype(row['oid'], row['rngsubtype'].to_i) do |subtype|
+              OID::Range.new(subtype, row['typname'].to_sym)
             end
           end
 
@@ -64,9 +64,13 @@ module ActiveRecord
             end
           end
 
-          def register(oid, oid_type)
-            oid = assert_valid_registration(oid, oid_type)
-            @store.register_type(oid, oid_type)
+          def register(oid, oid_type = nil, &block)
+            oid = assert_valid_registration(oid, oid_type || block)
+            if block_given?
+              @store.register_type(oid, &block)
+            else
+              @store.register_type(oid, oid_type)
+            end
           end
 
           def alias_type(oid, target)
@@ -74,6 +78,14 @@ module ActiveRecord
             @store.alias_type(oid, target)
           end
 
+          def register_with_subtype(oid, target_oid)
+            if @store.key?(target_oid)
+              register(oid) do |_, *args|
+                yield @store.lookup(target_oid, *args)
+              end
+            end
+          end
+
           def assert_valid_registration(oid, oid_type)
             raise ArgumentError, "can't register nil type for OID #{oid}" if oid_type.nil?
             oid.to_i
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 3a60de1f28..6ef47d8a11 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -516,9 +516,12 @@ module ActiveRecord
 
         def extract_limit(sql_type) # :nodoc:
           case sql_type
-          when /^bigint/i;    8
-          when /^smallint/i;  2
-          else super
+          when /^bigint/i, /^int8/i
+            8
+          when /^smallint/i
+            2
+          else
+            super
           end
         end