deprecate implicit string casting of mapping keys

Author: xabbuh

CHANGELOG.md

@@ -4,6 +4,37 @@ CHANGELOG
 3.3.0
 -----
 
+ * Deprecated support for implicitly parsing non-string mapping keys as strings. Mapping keys that are no strings will
+   lead to a `ParseException` in Symfony 4.0. Use the `PARSE_KEYS_AS_STRINGS` flag to opt-in for keys to be parsed as
+   strings.
+
+   Before:
+
+   ```php
+   $yaml = <<<YAML
+   null: null key
+   true: boolean true
+   1: integer key
+   2.0: float key
+   YAML;
+
+   Yaml::parse($yaml);
+   ```
+
+   After:
+
+   ```php
+
+   $yaml = <<<YAML
+   null: null key
+   true: boolean true
+   1: integer key
+   2.0: float key
+   YAML;
+
+   Yaml::parse($yaml, Yaml::PARSE_KEYS_AS_STRINGS);
+   ```
+
  * Omitted mapping values will be parsed as `null`.
 
  * Omitting the key of a mapping is deprecated and will throw a `ParseException` in Symfony 4.0.

Inline.php

@@ -485,6 +485,14 @@ private static function parseMapping($mapping, $flags, &$i = 0, $references = ar
                 @trigger_error('Omitting the key of a mapping is deprecated and will throw a ParseException in 4.0.', E_USER_DEPRECATED);
             }
 
+            if (!(Yaml::PARSE_KEYS_AS_STRINGS & $flags)) {
+                $evaluatedKey = self::evaluateScalar($key, $flags, $references);
+
+                if ('' !== $key && $evaluatedKey !== $key && !is_string($evaluatedKey)) {
+                    @trigger_error('Implicit casting of incompatible mapping keys to strings is deprecated since version 3.3 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0. Pass the PARSE_KEYS_AS_STRING flag to explicitly enable the type casts.', E_USER_DEPRECATED);
+                }
+            }
+
             if (':' !== $key && (!isset($mapping[$i + 1]) || !in_array($mapping[$i + 1], array(' ', ',', '[', ']', '{', '}'), true))) {
                 @trigger_error('Using a colon that is not followed by an indication character (i.e. " ", ",", "[", "]", "{", "}" is deprecated since version 3.2 and will throw a ParseException in 4.0.', E_USER_DEPRECATED);
             }

Parser.php

@@ -180,14 +180,19 @@ public function parse($value, $flags = 0)
                 Inline::parse(null, $flags, $this->refs);
                 try {
                     Inline::$parsedLineNumber = $this->getRealCurrentLineNb();
-                    $key = Inline::parseScalar($values['key']);
+                    $i = 0;
+                    $key = Inline::parseScalar($values['key'], 0, null, $i, !(Yaml::PARSE_KEYS_AS_STRINGS & $flags));
                 } catch (ParseException $e) {
                     $e->setParsedLine($this->getRealCurrentLineNb() + 1);
                     $e->setSnippet($this->currentLine);
 
                     throw $e;
                 }
 
+                if (!(Yaml::PARSE_KEYS_AS_STRINGS & $flags) && !is_string($key)) {
+                    @trigger_error('Implicit casting of incompatible mapping keys to strings is deprecated since version 3.3 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0. Pass the PARSE_KEYS_AS_STRING flag to explicitly enable the type casts.', E_USER_DEPRECATED);
+                }
+
                 // Convert float keys to strings, to avoid being converted to integers by PHP
                 if (is_float($key)) {
                     $key = (string) $key;

Tests/DumperTest.php

@@ -125,7 +125,7 @@ public function testSpecifications()
                     // TODO
                 } else {
                     eval('$expected = '.trim($test['php']).';');
-                    $this->assertSame($expected, $this->parser->parse($this->dumper->dump($expected, 10)), $test['test']);
+                    $this->assertSame($expected, $this->parser->parse($this->dumper->dump($expected, 10), Yaml::PARSE_KEYS_AS_STRINGS), $test['test']);
                 }
             }
         }

Tests/Fixtures/YtsSpecificationExamples.yml

@@ -556,21 +556,6 @@ php: |
     'fixed' => 1230.15,
   )
 ---
-test: Miscellaneous
-spec: 2.21
-yaml: |
-  null: ~
-  true: true
-  false: false
-  string: '12345'
-php: |
-  array(
-    '' => null,
-    1 => true,
-    0 => false,
-    'string' => '12345'
-  )
----
 test: Timestamps
 todo: true
 spec: 2.22
@@ -1533,18 +1518,6 @@ ruby: |
   }
 
 ---
-test: Boolean
-yaml: |
-   false: used as key
-   logical:  true
-   answer: false
-php: |
-   array(
-     false => 'used as key',
-     'logical' => true,
-     'answer' => false
-   )
----
 test: Integer
 yaml: |
    canonical: 12345

Tests/Fixtures/YtsTypeTransfers.yml

@@ -210,20 +210,6 @@ php: |
       'negative one-thousand' => -1000.0
     )
 ---
-test: Integers as Map Keys
-brief: >
-    An integer can be used a dictionary key.
-yaml: |
-    1: one
-    2: two
-    3: three
-php: |
-    array(
-        1 => 'one',
-        2 => 'two',
-        3 => 'three'
-    )
----
 test: Floats
 dump_skip: true
 brief: >

Tests/Fixtures/booleanMappingKeys.yml

@@ -0,0 +1,11 @@
+--- %YAML:1.0
+test: Miscellaneous
+spec: 2.21
+yaml: |
+  true: true
+  false: false
+php: |
+  array(
+    'true' => true,
+    'false' => false,
+  )

Tests/Fixtures/legacyBooleanMappingKeys.yml

@@ -0,0 +1,23 @@
+--- %YAML:1.0
+test: Miscellaneous
+spec: 2.21
+yaml: |
+  true: true
+  false: false
+php: |
+  array(
+    1 => true,
+    0 => false,
+  )
+---
+test: Boolean
+yaml: |
+   false: used as key
+   logical:  true
+   answer: false
+php: |
+   array(
+     false => 'used as key',
+     'logical' => true,
+     'answer' => false
+   )

Tests/Fixtures/legacyNonStringKeys.yml

@@ -0,0 +1,2 @@
+- legacyBooleanMappingKeys
+- legacyNullMappingKey

Tests/Fixtures/legacyNullMappingKey.yml

@@ -0,0 +1,9 @@
+--- %YAML:1.0
+test: Miscellaneous
+spec: 2.21
+yaml: |
+  null: ~
+php: |
+  array(
+    '' => null,
+  )