run-tests: remove unnecessary variable initialisation ret is always set before it is used, so remove ret = 0

histedit: clarify description of fold command N and (N-1) didn't add any information to description of fold. More useful is refering to the commit list as it is displayed in editor.

discovery: make "note: unsynced remote changes!" less serious than a warning This situation is not necessarily a problem and do not deserve a warning. It is just some information that can guide the user in understanding what is going on. Making it 'debug' would usually not give the hint when it is relevant so we make it a 'status' message.

discovery: improve "note: unsynced remote changes!" warning This message frequently caused confusion. "unsynced" is not a well established user-facing concept in Mercurial and the message was not very specific or helpful. Instead, show a message like: remote has heads on branch 'default' that are not known locally: 6c0482d977a3 This message will also (when relevant) be shown before aborting on "push creates new remote head". A similar (but actually very different) message was addressed in 6b618aa08b6e.

import: move tryone closure in cmdutil We extract the `tryone` function into the `cmdutil` module. A lot of the command context have to be passed to the utility function, but having and explicit declaration will allow extension to wrap it. This will allows use to make changeset evolution related experiment in dedicated extension. Improving the API of this function is noble goal but outside of the scope of this patches.

revset: optimize missing ancestor expressions A missing ancestor expression is any expression of the form (::x - ::y) or equivalent. Such expressions are remarkably common, and so far have involved multiple walks down the DAG, followed by a set difference operation. With this patch, such expressions will be transformed into uses of the fast algorithm at ancestor.missingancestor. For a repository with over 600,000 revisions, perfrevset for '::tip - ::-10000' returns: Before: ! wall 3.999575 comb 4.000000 user 3.910000 sys 0.090000 (best of 3) After: ! wall 0.132423 comb 0.130000 user 0.130000 sys 0.000000 (best of 75)

revset: add an undocumented _missingancestors function This will be used in an upcoming patch to optimize expressions of the form (::x - ::y).

commands.debugrevspec: add an option to print the optimized expression tree This will be used in an upcoming patch to test that the optimizer works.

tests: killdaemons.py for windows distinguishes access violation and terminated To distinguish between access violaition (process belonging to another user) and a terminated process, PROCESS_QUERY_INFORMATION must be enabled. But TerminateProcess still raises error 5 in both cases. Therefore check before if the process has already terminated.

tests: killdaemons.py for checks reason when getting no process handle