index: move raise_revlog_error() further up I will add another caller below it. Differential Revision: https://phab.mercurial-scm.org/D4119

index: make node tree a Python object Differential Revision: https://phab.mercurial-scm.org/D4118

index: rename _fix_index() since it no longer fixes the index Since c0d411ea6639 (index: drop support for negative indexes into the index, 2018-07-20), it always returns the input (unless it raises). Differential Revision: https://phab.mercurial-scm.org/D4334

index: don't include nullid in boundary check in pure code Yet another change that should probably have been part of a3dacabd476b (index: don't allow index[len(index)] to mean nullid, 2018-07-20). Differential Revision: https://phab.mercurial-scm.org/D4333

fastannotate: address pyflakes concerns Two unused imports, one unused local variable assignment. Differential Revision: https://phab.mercurial-scm.org/D4337

fastannotate: move some global state mutation to extsetup() Differential Revision: https://phab.mercurial-scm.org/D4202