repair: mark the critical section of strip() as unsafe When our experimental nointerrupt feature is enabled, this will help prevent users from corrupting their repo during a strip. Differential Revision: https://phab.mercurial-scm.org/D3717

ui: add an uninterruptable context manager that can block SIGINT The blocking of SIGINT is not done by default, but my hope is that we will one day. This was inspired by Facebook's "nointerrupt" extension, which is a bit more heavy-handed than this (whole commands are treated as unsafe to interrupt). A future patch will enable this for varying bits of Mercurial that are performing unsafe operations. It's intentional that the KeyboardInterrupt is raised as the context manager exits: during the span of the context manager interrupting Mercurial could lead to data loss, but typically those spans are fairly narrow, so we can let the unsafe block complete and then terminate hg (which will leave the repo in a consistent state, even if it's not the user's desired state). .. api:: New context manager ``ui.uninterruptable()`` to mark portions of a command as potentially unsafe places to interrupt Mercurial with Control-C or similar. Differential Revision: https://phab.mercurial-scm.org/D3716

merge with stable

revset: add partial support for ancestor(wdir()) It's easy, so let's make it happen. I'm not certain if 'wdir() &' should be required. ancestors(wdir()) works without it, but ancestor(wdir()) doesn't as of now. That's the issue of fullreposet.__contains__() vs __and__().

context: also accept diff option directly For now we accept both diff option and dictionary. This will let us upgrade internal users gradually before we drop the old API at the end of this series.

context: also take all other arguments than `patch.diff` accept This is needed to use `context.diff` as a full replacement of `patch.diff`

context: explicitly take diffopts in `context.diff` (API) To provide a proper replacement for the `patch.diff(…)` function, the `context.diff(…)` method needs to be able to take more parameters. To distinguish the diff options from the new other arguments, we upgrade the diff options to its own explicit argument.

rebase: check whether the rebasestate exists or not a bit early Converted the else part into `if True` because that part will soon be under a except part. Differential Revision: https://phab.mercurial-scm.org/D3876