[Yaml] Deprecate using the non-specific tag

UPGRADE-3.4.md

@@ -10,7 +10,7 @@ Finder
 ------
 
  * The `Symfony\Component\Finder\Iterator\FilterIterator` class has been
-   deprecated and will be removed in 4.0 as it used to fix a bug which existed 
+   deprecated and will be removed in 4.0 as it used to fix a bug which existed
    before version 5.5.23/5.6.7.
 
 Validator
@@ -18,3 +18,9 @@ Validator
 
  * Not setting the `strict` option of the `Choice` constraint to `true` is
    deprecated and will throw an exception in Symfony 4.0.
+
+Yaml
+----
+
+ * Using the non-specific tag `!` is deprecated and will have a different
+   behavior in 4.0. Use a plain integer or `!!float` instead.

UPGRADE-4.0.md

@@ -685,3 +685,6 @@ Yaml
 
  * The constructor arguments `$offset`, `$totalNumberOfLines` and
    `$skippedLineNumbers` of the `Parser` class were removed.
+
+ * The behavior of the non-specific tag `!` is changed and now forces
+   non-evaluating your values.

src/Symfony/Component/Yaml/CHANGELOG.md

@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+3.4.0
+-----
+
+ * Deprecated using the non-specific tag `!` as its behavior will change in 4.0.
+   It will force non-evaluating your values in 4.0. Use plain integers or `!!float` instead.
+
 3.3.0
 -----
 

src/Symfony/Component/Yaml/Inline.php

@@ -611,6 +611,8 @@ class Inline
                     case 0 === strpos($scalar, '!str'):
                         return (string) substr($scalar, 5);
                     case 0 === strpos($scalar, '! '):
+                        @trigger_error('Using the non-specific tag "!" is deprecated since version 3.4 as its behavior will change in 4.0. It will force non-evaluating your values in 4.0. Use plain integers or !!float instead.', E_USER_DEPRECATED);
+
                         return (int) self::parseScalar(substr($scalar, 2), $flags);
                     case 0 === strpos($scalar, '!php/object:'):
                         if (self::$objectSupport) {

src/Symfony/Component/Yaml/Tests/Fixtures/YtsSpecificationExamples.yml

@@ -928,6 +928,7 @@ documents: 2
 
 ---
 test: Explicit typing
+deprecated: Using the non-specific tag "!" is deprecated since version 3.4 as its behavior will change in 4.0.
 yaml: |
    integer: 12
    also int: ! "12"

src/Symfony/Component/Yaml/Tests/ParserTest.php

@@ -61,7 +61,7 @@ class ParserTest extends TestCase
             restore_error_handler();
 
             $this->assertCount(1, $deprecations);
-            $this->assertContains('Using the comma as a group separator for floats is deprecated since version 3.2 and will be removed in 4.0.', $deprecations[0]);
+            $this->assertContains(true !== $deprecated ? $deprecated : 'Using the comma as a group separator for floats is deprecated since version 3.2 and will be removed in 4.0.', $deprecations[0]);
         }
     }