Fix tx template delete query.

i18n/en.json

@@ -502,7 +502,7 @@
     "subscribers.status.unconfirmed": "Unconfirmed",
     "subscribers.status.unsubscribed": "Unsubscribed",
     "subscribers.subscribersDeleted": "{num} subscriber(s) deleted",
-    "templates.cantDeleteDefault": "Cannot delete default template",
+    "templates.cantDeleteDefault": "Cannot delete non-existent or default template",
     "templates.default": "Default",
     "templates.dummyName": "Dummy campaign",
     "templates.dummySubject": "Dummy campaign subject",

internal/core/templates.go

@@ -1,6 +1,7 @@
 package core
 
 import (
+	"database/sql"
 	"net/http"
 
 	"github.com/knadh/listmonk/models"
@@ -74,8 +75,7 @@ func (c *Core) SetDefaultTemplate(id int) error {
 // DeleteTemplate deletes a given template.
 func (c *Core) DeleteTemplate(id int) error {
 	var delID int
-	if err := c.q.DeleteTemplate.Get(&delID, id); err != nil {
-		// TODO: Fix this. Deletes but always throws a "no result set" error.
+	if err := c.q.DeleteTemplate.Get(&delID, id); err != nil && err != sql.ErrNoRows {
 		return echo.NewHTTPError(http.StatusInternalServerError,
 			c.i18n.Ts("globals.messages.errorDeleting", "name", "{globals.terms.template}", "error", pqErrMsg(err)))
 	}

queries.sql

@@ -776,10 +776,12 @@ WITH tpl AS (
     DELETE FROM templates WHERE id = $1 AND (SELECT COUNT(id) FROM templates) > 1 AND is_default = false RETURNING id
 ),
 def AS (
-    SELECT id FROM templates WHERE is_default = true LIMIT 1
-)
+    SELECT id FROM templates WHERE is_default = true AND type='campaign' LIMIT 1
+),
+up AS (
     UPDATE campaigns SET template_id = (SELECT id FROM def) WHERE (SELECT id FROM tpl) > 0 AND template_id = $1
-    RETURNING (SELECT id FROM tpl);
+)
+SELECT id FROM tpl;
 
 
 -- media