Allow changing text and blob size without giving the `limit` option

In MySQL, the text column size is 65,535 bytes by default (1 GiB in
PostgreSQL). It is sometimes too short when people want to use a text
column, so they sometimes change the text size to mediumtext (16 MiB) or
longtext (4 GiB) by giving the `limit` option.

Unlike MySQL, PostgreSQL doesn't allow the `limit` option for a text
column (raises ERROR: type modifier is not allowed for type "text").
So `limit: 4294967295` (longtext) couldn't be used in Action Text.

I've allowed changing text and blob size without giving the `limit`
option, it prevents that migration failure on PostgreSQL.

3 files changed, 35 insertions, 9 deletions

diff --git a/activerecord/test/cases/migration_test.rb b/activerecord/test/cases/migration_test.rb
index 46e2ff79d9..02031e51ef 100644
--- a/activerecord/test/cases/migration_test.rb
+++ b/activerecord/test/cases/migration_test.rb
@@ -626,6 +626,18 @@ class MigrationTest < ActiveRecord::TestCase
     ensure
       Person.connection.drop_table :test_text_limits, if_exists: true
     end
+
+    def test_invalid_text_size_should_raise
+      e = assert_raise(ArgumentError) do
+        Person.connection.create_table :test_text_sizes, force: true do |t|
+          t.text :bigtext, size: 0xfffffffff
+        end
+      end
+
+      assert_match(/#{0xfffffffff} is invalid :size value\. Only :tiny, :medium, and :long are allowed\./, e.message)
+    ensure
+      Person.connection.drop_table :test_text_sizes, if_exists: true
+    end
   end
 
   if ActiveRecord::Base.connection.supports_advisory_locks?
diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
index dda3efa47c..49e9be9565 100644
--- a/activerecord/test/cases/schema_dumper_test.rb
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -245,25 +245,31 @@ class SchemaDumperTest < ActiveRecord::TestCase
 
   if current_adapter?(:Mysql2Adapter)
     def test_schema_dump_includes_length_for_mysql_binary_fields
-      output = standard_dump
+      output = dump_table_schema "binary_fields"
       assert_match %r{t\.binary\s+"var_binary",\s+limit: 255$}, output
       assert_match %r{t\.binary\s+"var_binary_large",\s+limit: 4095$}, output
     end
 
     def test_schema_dump_includes_length_for_mysql_blob_and_text_fields
-      output = standard_dump
-      assert_match %r{t\.blob\s+"tiny_blob",\s+limit: 255$}, output
+      output = dump_table_schema "binary_fields"
+      assert_match %r{t\.binary\s+"tiny_blob",\s+size: :tiny$}, output
       assert_match %r{t\.binary\s+"normal_blob"$}, output
-      assert_match %r{t\.binary\s+"medium_blob",\s+limit: 16777215$}, output
-      assert_match %r{t\.binary\s+"long_blob",\s+limit: 4294967295$}, output
-      assert_match %r{t\.text\s+"tiny_text",\s+limit: 255$}, output
+      assert_match %r{t\.binary\s+"medium_blob",\s+size: :medium$}, output
+      assert_match %r{t\.binary\s+"long_blob",\s+size: :long$}, output
+      assert_match %r{t\.text\s+"tiny_text",\s+size: :tiny$}, output
       assert_match %r{t\.text\s+"normal_text"$}, output
-      assert_match %r{t\.text\s+"medium_text",\s+limit: 16777215$}, output
-      assert_match %r{t\.text\s+"long_text",\s+limit: 4294967295$}, output
+      assert_match %r{t\.text\s+"medium_text",\s+size: :medium$}, output
+      assert_match %r{t\.text\s+"long_text",\s+size: :long$}, output
+      assert_match %r{t\.binary\s+"tiny_blob_2",\s+size: :tiny$}, output
+      assert_match %r{t\.binary\s+"medium_blob_2",\s+size: :medium$}, output
+      assert_match %r{t\.binary\s+"long_blob_2",\s+size: :long$}, output
+      assert_match %r{t\.text\s+"tiny_text_2",\s+size: :tiny$}, output
+      assert_match %r{t\.text\s+"medium_text_2",\s+size: :medium$}, output
+      assert_match %r{t\.text\s+"long_text_2",\s+size: :long$}, output
     end
 
     def test_schema_does_not_include_limit_for_emulated_mysql_boolean_fields
-      output = standard_dump
+      output = dump_table_schema "booleans"
       assert_no_match %r{t\.boolean\s+"has_fun",.+limit: 1}, output
     end
 
diff --git a/activerecord/test/schema/mysql2_specific_schema.rb b/activerecord/test/schema/mysql2_specific_schema.rb
index 61e9bc9af7..b143035213 100644
--- a/activerecord/test/schema/mysql2_specific_schema.rb
+++ b/activerecord/test/schema/mysql2_specific_schema.rb
@@ -27,6 +27,7 @@ ActiveRecord::Schema.define do
   create_table :binary_fields, force: true do |t|
     t.binary :var_binary, limit: 255
     t.binary :var_binary_large, limit: 4095
+
     t.tinyblob   :tiny_blob
     t.blob       :normal_blob
     t.mediumblob :medium_blob
@@ -36,6 +37,13 @@ ActiveRecord::Schema.define do
     t.mediumtext :medium_text
     t.longtext   :long_text
 
+    t.binary :tiny_blob_2, size: :tiny
+    t.binary :medium_blob_2, size: :medium
+    t.binary :long_blob_2, size: :long
+    t.text :tiny_text_2, size: :tiny
+    t.text :medium_text_2, size: :medium
+    t.text :long_text_2, size: :long
+
     t.index :var_binary
   end