logged errors: do not crash if formdef has been removed (#17036)

tests/test_backoffice_pages.py

@@ -3492,3 +3492,21 @@ def test_backoffice_logged_errors(pub):
     assert LoggedError.select()[0].acked is True
     resp = resp.click('Delete').follow()
     assert LoggedError.count() == 0
+
+    app = get_app(pub)
+    resp = app.get('/test/')
+    resp = resp.form.submit('submit').follow()
+    resp = resp.form.submit('submit')
+    assert LoggedError.count() == 1
+
+    app = login(get_app(pub))
+    resp = app.get('/backoffice/workflows/%s/' % workflow.id)
+    assert 'ZeroDivisionError' in resp.body
+    resp2 = resp.click('1 error')
+    resp = resp2.click('ZeroDivisionError')
+    assert 'href="http://example.net/backoffice/management/test/' in resp.body
+
+    # remove formdef
+    FormDef.wipe()
+    resp = resp2.click('ZeroDivisionError')
+    assert not 'href="http://example.net/backoffice/management/test/' in resp.body

wcs/admin/logged_errors.py

@@ -57,14 +57,15 @@ class LoggedErrorDirectory(Directory):
             r += htmltext('  <li>%s <a href="/backoffice/workflows/%s/">%s</a></li>') % (
                     _('Workflow: '), workflow.id, workflow.name)
 
-        formdata = self.error.get_formdata()
-        if formdata:
-            r += htmltext('  <li>%s <a href="%s">%s</a>') % (
-                    _('Data: '), formdata.get_url(backoffice=True),
-                    formdata.get_display_name())
-            r += htmltext(' (<a href="%sinspect">%s</a>)') % (
-                    formdata.get_url(backoffice=True), _('inspector'))
-            r += htmltext('</li>')
+        if formdef:
+            formdata = self.error.get_formdata()
+            if formdata:
+                r += htmltext('  <li>%s <a href="%s">%s</a>') % (
+                        _('Data: '), formdata.get_url(backoffice=True),
+                        formdata.get_display_name())
+                r += htmltext(' (<a href="%sinspect">%s</a>)') % (
+                        formdata.get_url(backoffice=True), _('inspector'))
+                r += htmltext('</li>')
 
         r += htmltext('</ul>')
         parts = (N_('Exception'), N_('Stack trace (most recent call first)'),