store: Skip null values in fulltext field reconstruction

When inserting rows with fulltext search columns, null source field
values caused "fulltext fields must be strings but got Null" errors.
Filter out null values the same way missing fields are already
filtered, since a null field shouldn't contribute to the fulltext
index.

Author: lutter

store/postgres/src/relational_queries.rs

@@ -2318,7 +2318,7 @@ impl<'a> InsertRow<'a> {
             let iv = if let Some(fields) = column.fulltext_fields.as_ref() {
                 let fulltext_field_values: Vec<_> = fields
                     .iter()
-                    .filter_map(|field| row.entity.get(field))
+                    .filter_map(|field| row.entity.get(field).filter(|v| !v.is_null()))
                     .map(|value| match value {
                         Value::String(s) => Ok(s),
                         _ => Err(internal_error!(
@@ -2378,6 +2378,7 @@ impl<'a> InsertRow<'a> {
                                     .iter()
                                     .find(|(w, _)| w.as_str() == src_col.name.as_str())
                                     .map(|(_, v)| v)
+                                    .filter(|v| !v.is_null())
                             })
                     })
                     .map(|value| match value {