rust-revlog: add invalidation detection to `NodeTree` class
This will be useful for callers, such as `scmutil` who reuse a
`NodeTree` instance as a cache. They would otherwise get hard
errors if any mutation of the index occurred since instantiation.
This is something the C index does not provide.
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}