Do not autocomplete if only whitespace precedes cursor

src/Psy/TabCompletion/AutoCompleter.php

@@ -62,6 +62,10 @@ public function processCallback($input, $index, $info = array())
             $line = $input;
         }
 
+        if ($this->shouldInsertOnlyTab($line, $info['point'])) {
+            return array("\t");
+        }
+
         $tokens = token_get_all('<?php ' . $line);
 
         // remove whitespaces
@@ -81,13 +85,30 @@ public function processCallback($input, $index, $info = array())
         return !empty($matches) ? $matches : array('');
     }
 
+    /**
+     * @param string $line  Readline current line
+     * @param int    $point The cursor position on the line
+     *
+     * @return bool true if the characters before $point are only whitespace
+     *
+     * @internal param int $index Current word index
+     */
+    private function shouldInsertOnlyTab($line, $point)
+    {
+        $precedingInput = substr($line, 0, $point);
+
+        $trimmedInput = trim($precedingInput);
+
+        return $trimmedInput === '';
+    }
+
     /**
      * The readline_completion_function callback handler.
      *
      * @see processCallback
      *
-     * @param $input
-     * @param $index
+     * @param string $input
+     * @param int    $index
      *
      * @return array
      */

test/Psy/Test/TabCompletion/AutoCompleterTest.php

@@ -61,7 +61,8 @@ public function testClassesCompletion($line, $mustContain, $mustNotContain)
 
         $code = $tabCompletion->processCallback('', 0, array(
            'line_buffer' => $line,
-           'point'       => 0,
+           'start'       => 0,
+           'point'       => strlen($line),
            'end'         => strlen($line),
         ));