Reworked what happens in install hooks. Coder.

islandora_basic_image/islandora_basic_image.install

@@ -9,6 +9,8 @@
  * Implements hook_install().
  */
 function islandora_basic_image_install() {
+  module_load_include('inc', 'islandora', 'include/fields.inc');
+
   // Ensure the basic image node type is available.
   node_types_rebuild();
 
@@ -35,16 +37,5 @@ function islandora_basic_image_install() {
     drupal_set_message($t('Field %name was created successfully', array('%name' => ISLANDORA_BASIC_IMAGE_MEDIUM_SIZE_FIELD)));
   }
 
-  if (field_info_field(ISLANDORA_TN_FIELD)) {
+  islandora_add_fields_to_bundle(ISLANDORA_BASIC_IMAGE_CONTENT_TYPE);
-    $tn_field_instance = array(
-      'field_name' => ISLANDORA_TN_FIELD,
-      'entity_type' => 'node',
-      'bundle' => ISLANDORA_BASIC_IMAGE_CONTENT_TYPE,
-      'label' => $t("Thumbnail"),
-      'description' => $t("A thumbnail for the Fedora resource"),
-      'required' => FALSE,
-    );
-    field_create_instance($tn_field_instance);
-    drupal_set_message($t('Field %name was created successfully', array('%name' => ISLANDORA_TN_FIELD)));
-  }
 }

islandora_collection/include/fields.inc

@@ -1,41 +0,0 @@
-<?php
-
-/**
- * @file
- * Utility functions for attaching default fields to collections.
- */
-
-/**
- * Attaches default fields for this module's content type.
- */
-function islandora_collection_attach_default_fields() {
-  $t = get_t();
-
-  // Add thumbnail field.
-  if (field_info_field(ISLANDORA_TN_FIELD)) {
-    $tn_field_instance = array(
-      'field_name' => ISLANDORA_TN_FIELD,
-      'entity_type' => 'node',
-      'bundle' => ISLANDORA_COLLECTION_CONTENT_TYPE,
-      'label' => $t("Thumbnail"),
-      'description' => $t("A thumbnail for the Fedora resource"),
-      'required' => FALSE,
-    );
-    field_create_instance($tn_field_instance);
-    drupal_set_message($t('Field %name was created successfully', array('%name' => ISLANDORA_TN_FIELD)));
-  }
-
-  // Add MODS field.
-  if (field_info_field(ISLANDORA_MODS_FIELD)) {
-    $mods_field_instance = array(
-      'field_name' => ISLANDORA_MODS_FIELD,
-      'entity_type' => 'node',
-      'bundle' => ISLANDORA_COLLECTION_CONTENT_TYPE,
-      'label' => $t("MODS"),
-      'description' => $t("A MODS record for the Fedora resource"),
-      'required' => FALSE,
-    );
-    field_create_instance($mods_field_instance);
-    drupal_set_message($t('Field %name was created successfully', array('%name' => ISLANDORA_MODS_FIELD)));
-  }
-}

islandora_collection/islandora_collection.install

@@ -9,14 +9,14 @@
  * Implements hook_install().
  */
 function islandora_collection_install() {
-  module_load_include('inc', 'islandora_collection', 'include/fields');
+  module_load_include('inc', 'islandora', 'include/fields.inc');
   module_load_include('inc', 'islandora_collection', 'include/relations');
 
   // Ensure the collection node type is available.
   node_types_rebuild();
 
-  // Create the islandora:collection content type.
+  // Add default Islandora fields.
-  islandora_collection_attach_default_fields();
+  islandora_add_fields_to_bundle(ISLANDORA_BASIC_IMAGE_CONTENT_TYPE);
 
   // Create the pcdm:hasMember relation.
   islandora_collection_define_relations();