forms: Properly export choices lists

Previously, this was not ported properly now that multiple selections are
supported in the choice field and derivatives.

include/class.dynamic_forms.php

@@ -1126,16 +1126,18 @@ class SelectionField extends FormField {
             $value = JsonDataParser::parse($value) ?: $value;
 
         if (!is_array($value)) {
-            $config = $this->getConfiguration();
-            if (!$config['multiselect']) {
-                // CDATA may be built with comma-list
-                list($value,) = explode(',', $value, 2);
-            }
+            $values = array();
             $choices = $this->getChoices();
-            if (isset($choices[$value]))
-                $value = array($value => $choices[$value]);
-            elseif ($id && isset($choices[$id]))
-                $value = array($id => $choices[$id]);
+            foreach (explode(',', $value) as $V) {
+                if (isset($choices[$V]))
+                    $values[$V] = $choices[$V];
+            }
+            if ($id && isset($choices[$id]))
+                $values[$id] = $choices[$id];
+
+            if ($values)
+                return $values;
+            // else return $value unchanged
         }
         // Don't set the ID here as multiselect prevents using exactly one
         // ID value. Instead, stick with the JSON value only.
@@ -1253,13 +1255,6 @@ class SelectionField extends FormField {
         return $selection;
     }
 
-    function export($value) {
-        if ($value && is_numeric($value)
-                && ($item = DynamicListItem::lookup($value)))
-            return $item->toString();
-        return $value;
-    }
-
     function getFilterData() {
         $data = array(parent::getFilterData());
         if (($v = $this->getClean()) instanceof DynamicListItem) {

include/class.forms.php

@@ -946,27 +946,33 @@ class ChoiceField extends FormField {
 
     function to_php($value) {
         if (is_string($value))
-            $array = JsonDataParser::parse($value) ?: $value;
-        else
-            $array = $value;
-        $config = $this->getConfiguration();
-        if (!$config['multiselect']) {
-            if (is_array($array) && count($array) < 2) {
-                reset($array);
-                return key($array);
-            }
-            if (is_string($array) && strpos($array, ',') !== false) {
-                list($array,) = explode(',', $array, 2);
+            $value = JsonDataParser::parse($value) ?: $value;
+
+        // CDATA table may be built with comma-separated key,value,key,value
+        if (is_string($value)) {
+            $values = array();
+            $choices = $this->getChoices();
+            foreach (explode(',', $value) as $V) {
+                if (isset($choices[$V]))
+                    $values[$V] = $choices[$V];
             }
+            if (array_filter($values))
+                $value = $values;
         }
-        return $array;
+        $config = $this->getConfiguration();
+        if (!$config['multiselect'] && is_array($value) && count($value) < 2) {
+            reset($value);
+            return key($value);
+        }
+        return $value;
     }
 
     function toString($value) {
-        $selection = $this->getChoice($value);
-        return is_array($selection)
-            ? (implode(', ', array_filter($selection)) ?: $value)
-            : (string) $selection;
+        if (!is_array($value))
+            $value = $this->getChoice($value);
+        if (is_array($value))
+            return implode(', ', $value);
+        return (string) $value;
     }
 
     function getChoice($value) {