view tests/test-wireproto.py.out @ 25996:b12e00a05d57 stable

revset: prevent crash caused by empty group expression while optimizing "or"

An empty group expression "()" generates None in AST, so it should be tested
before destructuring a tuple.

"A | ()" is still evaluated to an error because I'm not sure whether "()"
represents an empty set or an empty expression (= a unit value). They are
identical in "or" operation, but they should be evaluated differently in
"and" operation.

  expression  empty set  unit value
  ----------  ---------  ----------
  ()          {}         A
  A & ()      {}         A
  A | ()      A          A

Hello, Foobar
['Hello, Fo, =;:<o', 'Hello, Bar']