bug symfony#23342 [Dotenv] parse escaped quotes in unquoted env var values (xabbuh)

This PR was merged into the 3.3 branch.

Discussion
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[Dotenv] parse escaped quotes in unquoted env var values

| Q             | A
| ------------- | ---
| Branch?       | 3.3
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Commits
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66a4fd7 parse escaped quotes in unquoted env var values

Author: fabpot

src/Symfony/Component/Dotenv/Dotenv.php

@@ -215,6 +215,10 @@ private function lexValue()
             $notQuoted = true;
             $prevChr = $this->data[$this->cursor - 1];
             while ($this->cursor < $this->end && "\n" !== $this->data[$this->cursor] && !((' ' === $prevChr || "\t" === $prevChr) && '#' === $this->data[$this->cursor])) {
+                if ('\\' === $this->data[$this->cursor] && isset($this->data[$this->cursor + 1]) && ('"' === $this->data[$this->cursor + 1] || "'" === $this->data[$this->cursor + 1])) {
+                    ++$this->cursor;
+                }
+
                 $value .= $prevChr = $this->data[$this->cursor];
                 ++$this->cursor;
             }

src/Symfony/Component/Dotenv/Tests/DotenvTest.php

@@ -94,6 +94,9 @@ public function getEnvData()
             array('FOO="  "', array('FOO' => '  ')),
             array('PATH="c:\\\\"', array('PATH' => 'c:\\')),
             array("FOO=\"bar\nfoo\"", array('FOO' => "bar\nfoo")),
+            array('FOO=BAR\\"', array('FOO' => 'BAR"')),
+            array("FOO=BAR\\'BAZ", array('FOO' => "BAR'BAZ")),
+            array('FOO=\\"BAR', array('FOO' => '"BAR')),
 
             // concatenated values