Lexer: fix handling of cut off json where string don't terminate

Author: glaubinix

src/Seld/JsonLint/Lexer.php

@@ -112,7 +112,11 @@ public function getFullUpcomingInput()
         $next = $this->match;
         if (substr($next, 0, 1) === '"' && substr_count($next, '"') === 1) {
             $len = \strlen($this->input);
-            $strEnd = min(strpos($this->input, '"', $this->offset + 1) ?: $len, strpos($this->input, "\n", $this->offset + 1) ?: $len);
+            if ($len === $this->offset) {
+                $strEnd = $len;
+            } else {
+                $strEnd = min(strpos($this->input, '"', $this->offset + 1) ?: $len, strpos($this->input, "\n", $this->offset + 1) ?: $len);
+            }
             $next .= substr($this->input, $this->offset, $strEnd - $this->offset);
         } elseif (\strlen($next) < 20) {
             $next .= substr($this->input, $this->offset, 20 - \strlen($next));

tests/JsonParserTest.php

@@ -269,4 +269,15 @@ public function testLongString()
         $json = '{"k":"' . str_repeat("a\\n",10000) . '"}';
         $this->assertEquals(json_decode($json), $parser->parse($json));
     }
+
+    public function testParseNoneTerminatingString()
+    {
+        $parser = new JsonParser();
+
+        try {
+            $this->assertEquals('', $parser->parse('{"'));
+        } catch (ParsingException $e) {
+            $this->assertContains('Invalid string, it appears you forgot to terminate a string', $e->getMessage());
+        }
+    }
 }