obsolete: add an allprecursors method mirroring allsuccessors one. Detection of bumped changeset should use `allprecursors(<mutable>)` instead or `allsuccessors(<immutable>)` so we need the all precursors function to exists.

perf: fix perfvolatilesets The repoview's `filteredrevs` has been renamed to `filterrevs` at some point. perf was never informed.

obsolete: improve allsuccessors doc string The fact original nodes are also yield is not obvious. We update the docstring to highlight it.

obsolete: fix bad comment We cannot afford such extra "with" they are far too pricy.

util: remove unused realpath (issue4063) util.realpath was in use for only 5 days from dbdb777502dc until it was backed out in c519cd8f0169 because it caused issue3077 and issue3071.

import-checker: suppress check-code about any() ast is a new enough module that this script can't work on any version of Python without any(), so we'll just use it.

import-checker: use any() and a genexp to avoid awkward for/else construction

import-checker: backout 40f79b9a2cc8 (issue4129) This patch backs out 40f79b9a2cc8, which caused test-module-imports.t to be skipped when the test was run using virtualenv. Since the test now passes when using virtualenv, the skip is no longer necessary.