revset-only: use `subset &` instead of filtering The & version is more likely to be optimised. only(.) before) wall 0.003216 comb 0.000000 user 0.000000 sys 0.000000 (best of 768) after) wall 0.001086 comb 0.000000 user 0.000000 sys 0.000000 (best of 2231) only(default, stable) before) wall 0.018469 comb 0.020000 user 0.020000 sys 0.000000 (best of 138) after) wall 0.015888 comb 0.010000 user 0.010000 sys 0.000000 (best of 156)

revset-_ancestor: use & instead of filter The & operation is more likely optimised. ::10 before) wall 0.028189 comb 0.030000 user 0.030000 sys 0.000000 (best of 100) after) wall 0.001050 comb 0.000000 user 0.000000 sys 0.000000 (best of 2326) ::tip before) wall 0.081132 comb 0.080000 user 0.080000 sys 0.000000 (best of 100) after) wall 0.055418 comb 0.050000 user 0.050000 sys 0.000000 (best of 100)

obsstore: record data as floating point in fm0 format For python struct module, "d" is double. But for python string formating, "d" is integer. We want to preserve the floating point nature of the data, so we store it in the metadata as floating point. We use "%r" to make sure we get as many significant digitis as necessary to restore the float to the exact same value on the other side. The fm1 is transmitting the information as float. The lack of this made fm1-stored markers not survive a round-trip to fm0 leading to duplicated markers (or two markers very alike).

bundle2: add a comment about addchangegroup source and url

pull: call the `b2x-transactionclose` hook when closing the transaction We need a wider set of hooks to process all the changes that happened during the pull transaction. We reuse the experimental `b2x-transactionclose` hook set from server's unbundle for consistency. This hook is experimental and will not remains as-is forever, but this will open the door for experimentation in 3.2.

revset-only: use __nonzero__ to check if a revset is empty For some smartsets, computing length is more expensive than checking if the set is empty.