bundle2: fix names for error part handler The name is not very important but copy paste banshee got there. We make distinctive name.

transaction: introduce a transaction ID, to be available to all hooks The transaction ID is built from the object ID and creation time stamp to make sure it is unique.

transaction: actually use tr.hookargs in pretxnclose The 'tr.hookargs' is a dictionary containing all the arguments to be passed to hooks. It is actually used for hooks now...

bundle2: use unbundle source as transaction name This is what a bundle 1 push is doing. This got caught by trying to run the whole test-suite using bundle2 for exchanges.

tags: have a different cache file per filter level Currently whichever filter level asks for tags last will write the data on disk. This create massive issues when tags are read for "visible" and "unfiltered" on large and multi headed repository (like Mozilla central). See issue4550 for details Each filter level recomputes its own cache without direct collaboration but they all share the same 'hgtagsfnodes' cache. And that is where most of the time is spent.

parsers: when available, use a presized dictionary for the file foldmap On a repo with over 300,000 files, this speeds up perffilefoldmap: before: wall 0.178421 comb 0.180000 user 0.160000 sys 0.020000 (best of 55) after: wall 0.164462 comb 0.160000 user 0.140000 sys 0.020000 (best of 59)