I hit this AssertionError using git hyper-blame.

Version: depot_tools 0b65e732b44fbbbd4e40062b4581c47a95afb36d
OS: Linux

git hyper-blame -i 4d59fb59 -i 0f782e18 af4e3c54 -- third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in

Traceback (most recent call last):
  File "git_hyper_blame.py", line 391, in <module>
    sys.exit(main(sys.argv[1:], stdout=less_input))
  File "git_hyper_blame.py", line 385, in main
    return hyper_blame(ignored, filename, args.revision, out=stdout, err=stderr)
  File "git_hyper_blame.py", line 311, in hyper_blame
    assert 1 <= lineno_previous <= len(parent_blame)
AssertionError