context: make unknown/ignored/clean of cached status empty for equivalence Before this patch, "workingctx.status" caches the result of "dirstate.status" directly into "self._status". But "dirstate.status" is invoked with False "list*" arguments in normal "self._status" accessing route, and this makes "unknown"/"ignored"/"clean" of status empty. This may cause unexpected result of code paths internally accessing to them (accessors for external usage are already removed by previous patch). This patch makes "unknown"/"ignored"/"clean" of cached status empty for equivalence. Making them empty is executed only when at least one of "unknown", "ignored" or "clean" has files, for efficiency.

templatefilters.json: stabilize output The json filter was previously iterating over keys in an object in an undefined order. Let's throw a sorted() in there so output is consistent. It's somewhat frightening that there are no tests for the json filter. Subsequent commits will add them, so we pass on the opportunity to add them here.

templatefilters.json: call functions The "changeset" template from hgweb is using a lambda in the "diffsummary" key. In preparation for enabling JSON output from hgweb, teach the json filter how to call functions.

merge with stable