test-transaction-safety: document the test schedule This helps reader to understand how the test work and actually helped me to detect a missing synchronisation step. Differential Revision: https://phab.mercurial-scm.org/D11215

rhg: Propagate permission errors when finding a repository The Rust standard library has a `Path::is_dir` method that returns false for any I/O error (such as a permission error), not just "No such file or directory". Instead add an `is_dir` function that returns false for non-directories and for "No such file or directory" errors, but propagates other I/O errors. Differential Revision: https://phab.mercurial-scm.org/D11230

rhg: Add build and config instructions to the README file This adds documentation explaining how to compile, configure, and use rhg as well as how the fallback mechanism works. Differential Revision: https://phab.mercurial-scm.org/D11229

dirstate: use `add` in the deprecation message about `add` The previous message was talking about `remove`. Differential Revision: https://phab.mercurial-scm.org/D11224

help: correct config.profiling.freq name (frequency->freq) Differential Revision: https://phab.mercurial-scm.org/D11217

run-tests: use a small timeout for chg instance There is case where the test runner fails to clean up the temporary files in that case, spawned chg instance can stay around for 1 hours. Getting them to shut down sooner cannot hurt. (We should also use a more robust approach for this cleanup) Differential Revision: https://phab.mercurial-scm.org/D11227

run-tests: do not inherit file descriptor when running a command This is one of the difference between python2 and python3 and could have been a reason why test hang with python2 + chg. This does not seems to help the hanging issue at all… However, now that this is written lets reduce the difference between python2 and python3. Differential Revision: https://phab.mercurial-scm.org/D11226