bug #35332 [Yaml][Inline] Fail properly on empty object tag and empty const tag (fancyweb)

This PR was merged into the 3.4 branch.

Discussion
----------

[Yaml][Inline] Fail properly on empty object tag and empty const tag

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Rework of https://github.com/symfony/symfony/pull/35208 to not end up in `parseScalar` with an empty string or a boolean (and thus, avoid unfriendly error such as `Trying to access array offset on value of type bool`).

Ping @xabbuh

Commits
-------

bdf02c0a7e [Yaml][Inline] Fail properly on empty object tag and empty const tag

src/Symfony/Component/Yaml/Inline.php

@@ -506,7 +506,12 @@ class Inline
 
             if ('!php/const' === $key) {
                 $key .= self::parseScalar($mapping, $flags, [':', ' '], $i, false, [], true);
-                $key = self::evaluateScalar($key, $flags);
+                if ('!php/const:' === $key && ':' !== $mapping[$i]) {
+                    $key = '';
+                    --$i;
+                } else {
+                    $key = self::evaluateScalar($key, $flags);
+                }
             }
 
             if (':' !== $key && false === $i = strpos($mapping, ':', $i)) {
@@ -692,6 +697,10 @@ class Inline
                         return null;
                     case 0 === strpos($scalar, '!php/object'):
                         if (self::$objectSupport) {
+                            if (!isset($scalar[12])) {
+                                return false;
+                            }
+
                             return unserialize(self::parseScalar(substr($scalar, 12)));
                         }
 
@@ -717,6 +726,10 @@ class Inline
                         return null;
                     case 0 === strpos($scalar, '!php/const'):
                         if (self::$constantSupport) {
+                            if (!isset($scalar[11])) {
+                                return '';
+                            }
+
                             $i = 0;
                             if (\defined($const = self::parseScalar(substr($scalar, 11), 0, null, $i, false))) {
                                 return \constant($const);

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

@@ -799,4 +799,47 @@ class InlineTest extends TestCase
             'negative octal number' => [-28, '-034'],
         ];
     }
+
+    /**
+     * @dataProvider phpObjectTagWithEmptyValueProvider
+     */
+    public function testPhpObjectWithEmptyValue($expected, $value)
+    {
+        $this->assertSame($expected, Inline::parse($value, Yaml::PARSE_OBJECT));
+    }
+
+    public function phpObjectTagWithEmptyValueProvider()
+    {
+        return [
+            [false, '!php/object'],
+            [false, '!php/object '],
+            [false, '!php/object  '],
+            [[false], '[!php/object]'],
+            [[false], '[!php/object ]'],
+            [[false, 'foo'], '[!php/object  , foo]'],
+        ];
+    }
+
+    /**
+     * @dataProvider phpConstTagWithEmptyValueProvider
+     */
+    public function testPhpConstTagWithEmptyValue($expected, $value)
+    {
+        $this->assertSame($expected, Inline::parse($value, Yaml::PARSE_CONSTANT));
+    }
+
+    public function phpConstTagWithEmptyValueProvider()
+    {
+        return [
+            ['', '!php/const'],
+            ['', '!php/const '],
+            ['', '!php/const  '],
+            [[''], '[!php/const]'],
+            [[''], '[!php/const ]'],
+            [['', 'foo'], '[!php/const  , foo]'],
+            [['' => 'foo'], '{!php/const: foo}'],
+            [['' => 'foo'], '{!php/const : foo}'],
+            [['' => 'foo', 'bar' => 'ccc'], '{!php/const  : foo, bar: ccc}'],
+        ];
+    }
 }