Yuya Nishihara <yuya@tcha.org> [Sun, 09 Aug 2015 16:09:41 +0900] rev 25996
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
Yuya Nishihara <yuya@tcha.org> [Sun, 09 Aug 2015 16:06:36 +0900] rev 25995
revset: prevent crash caused by empty group expression while optimizing "and"
An empty group expression "()" generates None in AST, so the optimizer have
to test it before destructuring a tuple. The error message, "missing argument",
is somewhat obscure, but it should be better than crash.