largefiles: adapt remotestore._getfile to batched statlfile 9e1616307c4c introduced batching of statlfile, but not all codepaths got converted. _getfile gave _stat garbage and got garbage back. The garbage didn't match the expected error codes and was thus interpreted as success. It could thus end up trying to fetch a largefile that didn't exist. Instead we now pass _stat valid input and handle both correct and invalid output correctly. This makes the code work as intended ... but it would probably be better if it didn't abort on missing largefiles, just like it happened to do before.

largefiles: don't allow corruption to propagate after detection basestore.get uses util.atomictempfile when checking and receiving a new largefile ... but the close/discard logic was too clever for largefiles. Largefiles relied on being able to discard the file and thus prevent it from being written to the store. That was however too brittle. lfutil.copyandhash closes the infile after writing to it ... with a 'blecch' comment. The discard was thus a silent noop, and as a result of that corruption would be detected ... and then the corrupted files would be used anyway. Instead we now use a tmp file and rename or unlink it after validating it. A better solution should be implemented ... but not now.

largefiles: adapt verify to batched remote statlfile (issue3780) 9e1616307c4c introduced batching of statlfile, but not all codepaths got converted. 'hg verify' with a remotestore could thus crash with TypeError: 'builtin_function_or_method' object is not iterable Also, the 'hash' variable was used without assigning to it. Don't use variable names that collide with Python built-in functions. Instead we use 'expecthash' as in localstore. The tests for this issue covers an untested area. The tests happens to also reveal incorrect attempts at getting non-existing largefiles, bad server side handling of that, and corruption issues - all to be fixed later.

largefiles: let wirestore._stat return stats as expected by remotestore verify - preparing for fixing verify crash.