comparison mercurial/util.py @ 43494:5d40317d42b7

dirs: reject consecutive slashes in paths

We shouldn't ever see those, and the fuzzer go really excited that if
it gives us a 65k string with 55k slashes in it we use a lot of RAM.

This is a better fix than what I tried in D7105. It was suggested by
Yuya, and I verified it does in fact cause the fuzzer to not OOM.

This is a revision of D7234, but with the missing set of an error
added. I added a unit test of the dirs behavior because I needed to
reason more carefully about the failure modes around consecutive
slashes.

Differential Revision: https://phab.mercurial-scm.org/D7252

43493:3a463e5e470b

                addpath(f)

    def addpath(self, path):
        dirs = self._dirs
        for base in finddirs(path):
            if base in dirs:
                dirs[base] += 1
                return
            dirs[base] = 1

43494:5d40317d42b7

                addpath(f)

    def addpath(self, path):
        dirs = self._dirs
        for base in finddirs(path):
            if base.endswith(b'/'):
                raise ValueError(
                    "found invalid consecutive slashes in path: %r" % base
                )
            if base in dirs:
                dirs[base] += 1
                return
            dirs[base] = 1