error: store filename and message on LookupError for later It may be useful to be able to get to the failed path and the underlying error message when catching a LookupError, so let's make them accessible.

bundle2.unbundlepart: implement seek() This implements a seek() method for unbundlepart. This allows on-disk bundle2 parts to behave enough like files for bundlerepo to handle them. A future patch will add support for bundlerepo to read the bundle2 files that are written when the experimental.strip-bundle2-version config option is used.

bundle2.unbundlepart: tell() implementation Keep track of how many bytes we've returned from read(); fairly straightforward.

bundle2.unbundlepart: keep an index of chunks and their locations In order to make unbundlepart seekable, we need to keep a record of where the chunks are so that we can go back to the correct point.

bundle2.unbundlepart: raise payloadchunks from a closure to a method In a future patch, seek() will need to make a new chunk iterator for the stream; this places it somewhere it can be called multiple times.

manifest: make lru size configurable On machines with lots of ram, it's beneficial to increase the lru size of the manifest cache. On a large repo, configuring the lru to be size 10 can shave a large rebase (~12 commits) down from 95s to 70s.

parsers: use k instead of n for PyArg_ParseTuple because python 2.4 is awful