amend: fix amend with copies in extras
If copy information is stored only in the commit extras and not in
filelogs, then they get lost on amend if the file wasn't also modified
in the working copy. That's because we create `filectx` object from
the old commit in those cases, and the `.copysource()` of such objects
read only from the filelog. This patch fixes it by always creating a
new `memfilectx` in these cases, passing the calculated copy
information to it.
Differential Revision: https://phab.mercurial-scm.org/D12387
{
// 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)
}