Issue #1876832: Fix pdftk path check.

fillpdf.admin.inc

@@ -36,7 +36,7 @@ function fillpdf_settings($form, &$form_state) {
   }
 
   // Check for pdftk.
-  $status = fillpdf_pdftk_check(variable_get('fillpdf_pdftk_path', 'pdftk'));
+  $status = fillpdf_pdftk_check(fillpdf_pdftk_path());
   if ($status === FALSE) {
     $options['pdftk'] .= '<div class="messages warning">' . t('pdftk is not properly installed.') . '</div>';
   }

fillpdf.module

@@ -710,7 +710,7 @@ function fillpdf_execute_merge($method, $fields, $fillpdf, $mode = 'url', $flatt
       $xfdffile = file_save_data($xfdf, $xfdfname, FILE_EXISTS_RENAME);
 
       // Now feed this to pdftk and save the result to a variable
-      $path_to_pdftk = variable_get('fillpdf_pdftk_path', 'pdftk');
+      $path_to_pdftk = fillpdf_pdftk_path();
       ob_start();
       passthru($path_to_pdftk . ' ' . escapeshellarg(drupal_realpath($filename)) . ' fill_form ' . escapeshellarg(drupal_realpath($xfdffile->uri)) . ' output - ' . ($flatten ? 'flatten ' : '') . 'drop_xfa');
       $data = ob_get_clean();
@@ -807,7 +807,7 @@ function fillpdf_execute_parse($method, $fillpdf, $mode = 'url') {
       break;
   }
 
-  $path_to_pdftk = variable_get('fillpdf_pdftk_path', 'pdftk');
+  $path_to_pdftk = fillpdf_pdftk_path();
   $status = fillpdf_pdftk_check($path_to_pdftk);
   if ($status === FALSE) {
     drupal_set_message(t('pdftk not properly installed.'), 'error');
@@ -1014,3 +1014,13 @@ function fillpdf_pdftk_check($pdftk_path = 'pdftk') {
   return TRUE;
 }
 
+// This is a convenience wrapper around variable_get(). It lets us **also**
+// return "pdftk" if the variable is empty, not just unset.
+function fillpdf_pdftk_path() {
+  $path_to_pdftk = variable_get('fillpdf_pdftk_path', 'pdftk');
+  if ($path_to_pdftk) {
+    return $path_to_pdftk;
+  }
+  return 'pdftk';
+}
+