[PATCH v1 1/4] xdrgen: Handle a union whose arms are all void

[Chuck Lever <cel@kernel.org>]

_XdrUnion.symbolic_width() assigns its result variable only when
an arm's width exceeds the running maximum, and the maximum starts
at zero. A union whose arms are all void has no such arm, so the
return statement reads a variable that was never bound. The
definitions command then reports "cannot access local variable
'width'" and exits without generating the header. The sibling
max_width() method starts from zero and handles the same union.

Start the symbolic width from an empty list, so an all-void union
reports just the width of its discriminant.

Fixes: ce5a75d9939f ("xdrgen: XDR width for union types")
Signed-off-by: Chuck Lever <cel@kernel.org>
---
 tools/net/sunrpc/xdrgen/xdr_ast.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/net/sunrpc/xdrgen/xdr_ast.py b/tools/net/sunrpc/xdrgen/xdr_ast.py
index 5b2a78ca745c..537f056a0c27 100644
--- a/tools/net/sunrpc/xdrgen/xdr_ast.py
+++ b/tools/net/sunrpc/xdrgen/xdr_ast.py
@@ -546,6 +546,7 @@ class _XdrUnion(_XdrAst):
     def symbolic_width(self) -> List:
         """Return list containing XDR width of type's components"""
         max_width = 0
+        width = []
         for case in self.cases:
             if case.arm.max_width() > max_width:
                 max_width = case.arm.max_width()
-- 
2.56.0