Use File::NULL instead of /dev/null

Some platforms (namely, Windows) use a path other than `/dev/null` to
point to the null device.  Ruby provides the `File::NULL` constant to
specify that path in a cross-platform way.

Author: jonathanhefner

activerecord/lib/active_record/tasks/postgresql_database_tasks.rb

@@ -81,7 +81,7 @@ def structure_dump(filename, extra_flags)
       end
 
       def structure_load(filename, extra_flags)
-        args = ["--set", ON_ERROR_STOP_1, "--quiet", "--no-psqlrc", "--output", "/dev/null", "--file", filename]
+        args = ["--set", ON_ERROR_STOP_1, "--quiet", "--no-psqlrc", "--output", File::NULL, "--file", filename]
         args.concat(Array(extra_flags)) if extra_flags
         args << db_config.database
         run_cmd("psql", args, "loading")

activerecord/test/cases/tasks/postgresql_rake_test.rb

@@ -531,7 +531,7 @@ def test_structure_load
         assert_called_with(
           Kernel,
           :system,
-          [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", "/dev/null", "--file", filename, @configuration["database"]],
+          [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", File::NULL, "--file", filename, @configuration["database"]],
           returns: true
         ) do
           ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
@@ -540,7 +540,7 @@ def test_structure_load
 
       def test_structure_load_with_extra_flags
         filename = "awesome-file.sql"
-        expected_command = [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", "/dev/null", "--file", filename, "--noop", @configuration["database"]]
+        expected_command = [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", File::NULL, "--file", filename, "--noop", @configuration["database"]]
 
         assert_called_with(Kernel, :system, expected_command, returns: true) do
           with_structure_load_flags(["--noop"]) do
@@ -552,7 +552,7 @@ def test_structure_load_with_extra_flags
       def test_structure_load_with_env
         filename = "awesome-file.sql"
         expected_env = { "PGHOST" => "my.server.tld", "PGPORT" => "2345", "PGUSER" => "jane", "PGPASSWORD" => "s3cr3t" }
-        expected_command = [expected_env, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", "/dev/null", "--file", filename, "--noop", @configuration["database"]]
+        expected_command = [expected_env, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", File::NULL, "--file", filename, "--noop", @configuration["database"]]
 
         assert_called_with(Kernel, :system, expected_command, returns: true) do
           with_structure_load_flags(["--noop"]) do
@@ -567,7 +567,7 @@ def test_structure_load_with_env
       def test_structure_load_with_ssl_env
         filename = "awesome-file.sql"
         expected_env = { "PGSSLMODE" => "verify-full", "PGSSLCERT" => "client.crt", "PGSSLKEY" => "client.key", "PGSSLROOTCERT" => "root.crt" }
-        expected_command = [expected_env, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", "/dev/null", "--file", filename, "--noop", @configuration["database"]]
+        expected_command = [expected_env, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", File::NULL, "--file", filename, "--noop", @configuration["database"]]
 
         assert_called_with(Kernel, :system, expected_command, returns: true) do
           with_structure_load_flags(["--noop"]) do
@@ -581,7 +581,7 @@ def test_structure_load_with_ssl_env
 
       def test_structure_load_with_hash_extra_flags_for_a_different_driver
         filename = "awesome-file.sql"
-        expected_command = [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", "/dev/null", "--file", filename, @configuration["database"]]
+        expected_command = [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", File::NULL, "--file", filename, @configuration["database"]]
 
         assert_called_with(Kernel, :system, expected_command, returns: true) do
           with_structure_load_flags({ mysql2: ["--noop"] }) do
@@ -592,7 +592,7 @@ def test_structure_load_with_hash_extra_flags_for_a_different_driver
 
       def test_structure_load_with_hash_extra_flags_for_the_correct_driver
         filename = "awesome-file.sql"
-        expected_command = [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", "/dev/null", "--file", filename, "--noop", @configuration["database"]]
+        expected_command = [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", File::NULL, "--file", filename, "--noop", @configuration["database"]]
 
         assert_called_with(Kernel, :system, expected_command, returns: true) do
           with_structure_load_flags({ postgresql: ["--noop"] }) do
@@ -606,7 +606,7 @@ def test_structure_load_accepts_path_with_spaces
         assert_called_with(
           Kernel,
           :system,
-          [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", "/dev/null", "--file", filename, @configuration["database"]],
+          [{}, "psql", "--set", "ON_ERROR_STOP=1", "--quiet", "--no-psqlrc", "--output", File::NULL, "--file", filename, @configuration["database"]],
           returns: true
         ) do
           ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)