Revise 'sqlite3:' URL handling for smoother upgrades

Restore the 4.0 behaviour for 'sqlite3:///', but deprecate it. We'll
change to the absolute-path interpretation in 4.2.

The current "correct" spellings for in-memory, relative, and absolute
URLs, respectively, are:

    sqlite3::memory:
    sqlite3:relative/path
    sqlite3:/full/path

Substantially reverses/defers fbb79b517f3127ba620fedd01849f9628b78d6ce.
Uncovered by @guilleiguaran while investigating #14495, though that
sounds like a different issue.

3 files changed, 26 insertions, 7 deletions

diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index c2a255451e..14aad61ce2 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -31,7 +31,7 @@ module ActiveRecord
         def test_connect_with_url
           original_connection = ActiveRecord::Base.remove_connection
           tf = Tempfile.open 'whatever'
-          url = "sqlite3://#{tf.path}"
+          url = "sqlite3:#{tf.path}"
           ActiveRecord::Base.establish_connection(url)
           assert ActiveRecord::Base.connection
         ensure
@@ -42,7 +42,7 @@ module ActiveRecord
 
         def test_connect_memory_with_url
           original_connection = ActiveRecord::Base.remove_connection
-          url = "sqlite3:///:memory:"
+          url = "sqlite3::memory:"
           ActiveRecord::Base.establish_connection(url)
           assert ActiveRecord::Base.connection
         ensure
diff --git a/activerecord/test/cases/connection_specification/resolver_test.rb b/activerecord/test/cases/connection_specification/resolver_test.rb
index fdd1914cba..a4fe87049a 100644
--- a/activerecord/test/cases/connection_specification/resolver_test.rb
+++ b/activerecord/test/cases/connection_specification/resolver_test.rb
@@ -82,15 +82,34 @@ module ActiveRecord
           assert_equal password, spec["password"]
         end
 
-        def test_url_host_db_for_sqlite3
-          spec = resolve 'sqlite3://foo:bar@dburl:9000/foo_test'
+        def test_url_with_authority_for_sqlite3
+          spec = assert_deprecated { resolve 'sqlite3:///foo_test' }
+          assert_equal('foo_test', spec["database"])
+        end
+
+        def test_url_absolute_path_for_sqlite3
+          spec = resolve 'sqlite3:/foo_test'
           assert_equal('/foo_test', spec["database"])
         end
 
-        def test_url_host_memory_db_for_sqlite3
-          spec = resolve 'sqlite3://foo:bar@dburl:9000/:memory:'
+        def test_url_relative_path_for_sqlite3
+          spec = resolve 'sqlite3:foo_test'
+          assert_equal('foo_test', spec["database"])
+        end
+
+        def test_url_memory_db_for_sqlite3
+          spec = resolve 'sqlite3::memory:'
           assert_equal(':memory:', spec["database"])
         end
+
+        def test_url_sub_key_for_sqlite3
+          spec = resolve :production, 'production' => {"url" => 'sqlite3:foo?encoding=utf8'}
+          assert_equal({
+            "adapter"  => "sqlite3",
+            "database" => "foo",
+            "encoding" => "utf8" }, spec)
+        end
+
       end
     end
   end
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
index 1147418815..cf0235b8c5 100644
--- a/activerecord/test/cases/fixtures_test.rb
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -254,7 +254,7 @@ class FixturesTest < ActiveRecord::TestCase
 
   def test_fixtures_are_set_up_with_database_env_variable
     db_url_tmp = ENV['DATABASE_URL']
-    ENV['DATABASE_URL'] = "sqlite3:///:memory:"
+    ENV['DATABASE_URL'] = "sqlite3::memory:"
     ActiveRecord::Base.stubs(:configurations).returns({})
     test_case = Class.new(ActiveRecord::TestCase) do
       fixtures :accounts