Fix geometry type: perf, nil-limit crash, adapter pollution, and DDL hardening

- Build the RGeo factory, WKB/WKT parsers, and WKB generator once in the
  Geometry type's initializer instead of rebuilding them on every cast/
  serialize. A GEOS factory was previously allocated per value read; it is
  invariant per column. Eager construction (vs. lazy memoization) is also
  required because AR freezes Type instances after initialization.
- Guard the nil-limit path: a bare `geometry` column (no type/srid modifier)
  has no limit, so `limit[:srid]` raised NoMethodError on read. Add a `srid`
  helper defaulting to 0 (PostGIS "unknown SRID").
- type_to_sql: coerce srid with `to_i` so it cannot carry arbitrary text into
  the geometry() type modifier.
- Use `merge` instead of `merge!` for NATIVE_DATABASE_TYPES so the parent
  PostgreSQLAdapter's type map is not mutated with :geometry.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: waratuman

lib/active_record/connection_adapters/postgis/oid/geometry.rb

@@ -8,6 +8,19 @@ module OID
         class Geometry < Type::Value
           include ActiveModel::Type::Helpers::Mutable
 
+          # Build the RGeo factory, parsers and generator once, up front. The
+          # SRID is fixed for the column, so these are invariant for the life of
+          # the type instance. Doing it here (rather than lazily on each cast)
+          # avoids rebuilding a GEOS factory on every value read, and is
+          # required because Type instances are frozen after initialization.
+          def initialize(...)
+            super
+            @rgeo_factory = RGeo::Geos.factory(srid: srid)
+            @wkb_parser = RGeo::WKRep::WKBParser.new(@rgeo_factory, support_ewkb: true, default_srid: srid)
+            @wkt_parser = RGeo::WKRep::WKTParser.new(@rgeo_factory, support_ewkt: true, default_srid: srid)
+            @wkb_generator = RGeo::WKRep::WKBGenerator.new(hex_format: true, type_format: :ewkb, emit_ewkb_srid: true)
+          end
+
           def type
             :geometry
           end
@@ -20,9 +33,9 @@ def cast(value)
               value
             when ::String # HEXEWKB
               if value[0,1] == "\x00" || value[0,1] == "\x01" || value[0,4] =~ /[0-9a-fA-F]{4}/
-                RGeo::WKRep::WKBParser.new(rgeo_factory_generator, support_ewkb: true, default_srid: limit[:srid]).parse(value)
+                @wkb_parser.parse(value)
               else
-                RGeo::WKRep::WKTParser.new(rgeo_factory_generator, support_ewkt: true, default_srid: limit[:srid]).parse(value)
+                @wkt_parser.parse(value)
               end
             else
               raise ArgumentError, "Unsupported argument type (#{value.class})"
@@ -32,7 +45,7 @@ def cast(value)
           def serialize(value)
             case value
             when  RGeo::Feature::Instance
-              ::RGeo::WKRep::WKBGenerator.new(hex_format: true, type_format: :ewkb, emit_ewkb_srid: true).generate(value)
+              @wkb_generator.generate(value)
             else
               value
             end
@@ -44,8 +57,8 @@ def changed_in_place?(raw_old_value, new_value)
 
           private
 
-          def rgeo_factory_generator
-            RGeo::Geos.factory(srid: limit[:srid].to_i)
+          def srid
+            limit ? limit[:srid].to_i : 0
           end
 
         end

lib/active_record/connection_adapters/postgis/schema_statements.rb

@@ -14,7 +14,7 @@ def type_to_sql(sql_type, limit: nil, precision: nil, scale: nil, array: nil, ty
               type ||= 'Geometry'
               srid ||= 4326
             end
-            "geometry(#{type},#{srid})"
+            "geometry(#{type},#{srid.to_i})"
           else
             super
           end

lib/active_record/connection_adapters/postgis_adapter.rb

@@ -12,7 +12,7 @@ module ConnectionAdapters
     class PostGISAdapter < PostgreSQLAdapter
       ADAPTER_NAME = 'PostGIS'.freeze
 
-      NATIVE_DATABASE_TYPES = PostgreSQLAdapter::NATIVE_DATABASE_TYPES.merge!({
+      NATIVE_DATABASE_TYPES = PostgreSQLAdapter::NATIVE_DATABASE_TYPES.merge({
         geometry: { name: "geometry" },
       })