fsmonitor: use stringutil.forcebytestr() instead of str() on an exception Similar to 5fa8ac91190e / D7206, should get test-install.t passing on py3. Differential Revision: https://phab.mercurial-scm.org/D7218

py3: add a __str__ method to Abort This improves the rendering of some exceptions by avoiding raw bytestrings, especially when using --traceback option.

py3: add Python 3 exception output to test-lfs-serve-access.t Similar to a973a75e92bf or 3e9c6cef949b.

automation: install black This should unblock us from running the code formatting test in our automated environment. Differential Revision: https://phab.mercurial-scm.org/D7197

py3: use %d to format an int Avoids a TypeError under py3. Fortunately this is very much an edge case since it requires the user to have deliberately created a local tag of the form 'D\d+' that isn't truthful. Differential Revision: https://phab.mercurial-scm.org/D7215

fsmonitor: normalize exception types to bytes Unavailable.msg should now always be bytes. We also rename Unavailable.__str__ to __bytes__ as it always returns bytes. We make __str__ a simple wrapper that decodes that result to str. There's probably some excessive strutil.forcebytestr() in fsmonitor/__init__.py now. But at least the exceptions around type coercion should now be gone. Differential Revision: https://phab.mercurial-scm.org/D7214

fsmonitor: normalize clock value to bytes We normalize the value returned by watchman because we perform a number of compares with this value in code. So the easiest path forward is to normalize to bytes so we don't have to update many call sites. With this commit, the fsmonitor extension appears to be working with Python 3! Although there are still some failures in edge cases... Differential Revision: https://phab.mercurial-scm.org/D7213

fsmonitor: use next() instead of .next() This is needed for Python 3 compatibility. Differential Revision: https://phab.mercurial-scm.org/D7212

fsmonitor: normalize Watchman paths to bytes Otherwise it will be a str on Python 3 and operations below which operate in the bytes domain will fail. Differential Revision: https://phab.mercurial-scm.org/D7211

fsmonitor: handle unicode keys in tuples In Python 3, keys in the bset tuple are typically str, not bytes. PyBytes_AsString() would return NULL. But we weren't checking the return value and this would lead to a segfault. This commit makes the code type and Python version aware. The Python version specific code is to allow us to utilize a modern API for converting str -> char* without having to allocate an extra PyObject. FWIW I wanted to assume that keys were always str. However, there appear to be some bytes keys in some cases. I haven't debugged this further. Differential Revision: https://phab.mercurial-scm.org/D7210