3 files changed, 19 insertions, 0 deletions
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 8efefe9b2e..7f4be54dbb 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   Allow `ActionController::Parameters`-like objects to be passed as
+    values for Postgres HStore columns.
+
+    Fixes #26904.
+
+    *Jon Moss*
+
 *   Added `stat` method to `ActiveRecord::ConnectionAdapters::ConnectionPool`
 
     Example:
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
index a74a044a3a..d629ebca91 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
@@ -24,6 +24,8 @@ module ActiveRecord
           def serialize(value)
             if value.is_a?(::Hash)
               value.map { |k, v| "#{escape_hstore(k)}=>#{escape_hstore(v)}" }.join(", ")
+            elsif value.respond_to?(:to_unsafe_h)
+              serialize(value.to_unsafe_h)
             else
               value
             end
diff --git a/activerecord/test/cases/adapters/postgresql/hstore_test.rb b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
index c9982d3705..1f35300739 100644
--- a/activerecord/test/cases/adapters/postgresql/hstore_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
@@ -10,6 +10,12 @@ if ActiveRecord::Base.connection.supports_extensions?
       store_accessor :settings, :language, :timezone
     end
 
+    class FakeParameters
+      def to_unsafe_h
+        { "hi" => "hi" }
+      end
+    end
+
     def setup
       @connection = ActiveRecord::Base.connection
 
@@ -321,6 +327,10 @@ if ActiveRecord::Base.connection.supports_extensions?
       assert_match %r[t\.hstore "tags",\s+default: {}], output
     end
 
+    def test_supports_to_unsafe_h_values
+      assert_equal("\"hi\"=>\"hi\"", @type.serialize(FakeParameters.new))
+    end
+
     private
       def assert_array_cycle(array)
         # test creation