(fix)db: prevent invalid refs from crashing db update (#1816)

Previously when ROAM_REFS is non-empty, but the refs are invalid, this
will cause an empty SQL expression and crash the db caching. This fixes
that scenario.

CHANGELOG.md

@@ -11,6 +11,7 @@
 - [#1798](https://github.com/org-roam/org-roam/pull/1798) org-roam-node-at-point: do not skip invisible headings
 - [#1807](https://github.com/org-roam/org-roam/pull/1807) capture: always trigger `:if-new` template for existing nodes
 - [#1813](https://github.com/org-roam/org-roam/pull/1813) db: prevent empty ROAM_ALIASES from crashing db updates
+- [#1816](https://github.com/org-roam/org-roam/pull/1816) db: prevent invalid ROAM_REFS from crashing db updates
 
 ## 2.1.0
 ### Added

org-roam-db.el

@@ -418,9 +418,10 @@ If UPDATE-P is non-nil, first remove the file in the database."
                 (push (vector node-id (match-string 2 ref) (match-string 1 ref)) rows))
             (lwarn '(org-roam) :warning
                    "%s:%s\tInvalid ref %s, skipping..." (buffer-file-name) (point) ref))))
-      (org-roam-db-query [:insert :into refs
-                          :values $v1]
-                         rows))))
+      (when rows
+        (org-roam-db-query [:insert :into refs
+                            :values $v1]
+                           rows)))))
 
 (defun org-roam-db-insert-link (link)
   "Insert link data for LINK at current point into the Org-roam cache."