Catch missing configuration row for external choices

collect_app/src/main/java/org/odk/collect/android/dynamicpreload/ExternalDataUtil.java

@@ -167,6 +167,10 @@ public static ArrayList<SelectChoice> populateExternalChoices(FormEntryPrompt fo
             XPathFuncExpr xpathfuncexpr, FormController formController) throws FileNotFoundException {
         try {
             List<SelectChoice> selectChoices = formEntryPrompt.getSelectChoices();
+            if (containsConfigurationChoice(selectChoices)) {
+                String filePath = getFilePath(xpathfuncexpr, formController);
+                throw new FileNotFoundException(filePath);
+            }
             ArrayList<SelectChoice> returnedChoices = new ArrayList<>();
             for (SelectChoice selectChoice : selectChoices) {
                 String value = selectChoice.getValue();
@@ -212,14 +216,7 @@ public static ArrayList<SelectChoice> populateExternalChoices(FormEntryPrompt fo
             }
             return returnedChoices;
         } catch (Exception e) {
-            String fileName = String.valueOf(xpathfuncexpr.args[0].eval(null, null));
-            if (!fileName.endsWith(".csv")) {
-                fileName = fileName + ".csv";
-            }
-            String filePath = fileName;
-            if (formController != null) {
-                filePath = formController.getMediaFolder() + File.separator + fileName;
-            }
+            String filePath = getFilePath(xpathfuncexpr, formController);
             if (!new File(filePath).exists()) {
                 throw new FileNotFoundException(filePath);
             }
@@ -345,4 +342,30 @@ public static boolean isAnInteger(String value) {
             return false;
         }
     }
+
+    /**
+     * The config row is a special row in the choices worksheet that defines how
+     * choices are mapped from an external .csv file with list_name, name and label,
+     * where these correspond to columns in the .csv file.
+     */
+    private static boolean containsConfigurationChoice(List<SelectChoice> selectChoices) {
+        for (SelectChoice choice : selectChoices) {
+            if (!isAnInteger(choice.getValue())) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private static String getFilePath(XPathFuncExpr xpathfuncexpr, FormController formController) {
+        String fileName = String.valueOf(xpathfuncexpr.args[0].eval(null, null));
+        if (!fileName.endsWith(".csv")) {
+            fileName = fileName + ".csv";
+        }
+        String filePath = fileName;
+        if (formController != null) {
+            filePath = formController.getMediaFolder() + File.separator + fileName;
+        }
+        return filePath;
+    }
 }