dirstate-v2: Reuse existing nodes when appending to a data file
When writing a dirstate in v2 format by appending to an existing data file,
nodes that are still "unparsed" from the previous on-disk representation
have been unchanged and can therefore be reused.
This makes the new data point to previously-existing data for tree nodes.
Differential Revision: https://phab.mercurial-scm.org/D11095
{
// 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)
}