[META] Drupal 8 core must not use any deprecated code, must be enforced by automated testing

Is this a duplicate of #2959269: [meta] Core should not trigger deprecated code except in tests and during updates?

Re: #2: Not all deprecated code calls @trigger_error(), so we can't enforce with testing.

OK is there an issue for that or is the closest #2856742: [meta] Adopt trigger_error() for deprecation messages where it is missing ?

Here's a test where the failing results are classes marked @deprecated but which don't @trigger_error().

It requires symfony/finder. It has a bunch of limitations, and we shouldn't include this in core.

Limiting the discovery to the simpletest module, it shows output like this:

$ ./vendor/bin/phpunit -c core/ core/tests/FindDeprecatedTest.php 
PHPUnit 6.5.13 by Sebastian Bergmann and contributors.

Testing Drupal\Tests\FindDeprecatedTest
FF......................F..........                               35 / 35 (100%)

Time: 14.4 seconds, Memory: 6.00MB

There were 3 failures:

1) Drupal\Tests\FindDeprecatedTest::testEachFile with data set #0 ('/Users/paul/projects/drupal/c...er.php')
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'/Users/paul/projects/drupal/core/modules/simpletest/src/RouteProvider.php'
+''

/Users/paul/projects/drupal/core/tests/FindDeprecatedTest.php:72

2) Drupal\Tests\FindDeprecatedTest::testEachFile with data set #1 ('/Users/paul/projects/drupal/c...rt.php')
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'/Users/paul/projects/drupal/core/modules/simpletest/src/WebAssert.php'
+''

/Users/paul/projects/drupal/core/tests/FindDeprecatedTest.php:72

3) Drupal\Tests\FindDeprecatedTest::testEachFile with data set #24 ('/Users/paul/projects/drupal/c...er.php')
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'/Users/paul/projects/drupal/core/modules/simpletest/src/TestServiceProvider.php'
+''

/Users/paul/projects/drupal/core/tests/FindDeprecatedTest.php:72

FAILURES!
Tests: 35, Assertions: 41, Failures: 3.

Lo and behold those files have deprecated classes which don't @trigger_error().

Uploading this now because it's dinner time and if I run against the full file system it will take all evening. :-)

Really should have posted #8 in #2856744-11: [META] Add trigger_error(..., E_USER_DEPRECATED) to deprecated code

How are global constants going to be enforced with testing, eg

/**
 * Time of the current request in seconds elapsed since the Unix Epoch.
 * ...
 * @deprecated in drupal:8.3.0 and is removed from drupal:9.0.0.
 *   Use \Drupal::time()->getRequestTime();
 *
 * @see https://www.drupal.org/node/2785211
 */
define('REQUEST_TIME', (int) $_SERVER['REQUEST_TIME']);

This would only be a possible with a coverage report?

I don't think there is anything left here except #2959269: [meta] Core should not trigger deprecated code except in tests and during updates, which is basically the same meta with the actual sub-issues, should we promote that and close this?