diff --git a/hgext3rd/sparse.py b/hgext3rd/sparse.py
index 48290139d8..5a06f28586 100644
--- a/hgext3rd/sparse.py
+++ b/hgext3rd/sparse.py
@@ -24,7 +24,8 @@ cwdrealtivepatkinds = ('glob', 'relpath')
 
 def _fbsparseexists(ui):
     # internal config: extensions.fbsparse
-    return not ui.config('extensions', 'fbsparse', '!').startswith('!')
+    with self.ui.configoverride({("devel", "all-warnings"): False}):
+        return not ui.config('extensions', 'fbsparse', '!').startswith('!')
 
 def uisetup(ui):
     if _fbsparseexists(ui):