blackbox: adds a blackbox extension Adds a blackbox extension that listens to ui.log() and writes the messages to .hg/blackbox.log. Future commits will use ui.log() to log commands, unhandled exceptions, incoming changes, and hooks. The extension defaults to logging everything, but can be configured via blackbox.track to only log certain events. Log lines are of the format: "date time user> message" Example log line: 2013/02/09 08:35:19 durham> 1 incoming changes - new heads: d84ced58aaa

scmutil: create directories in a race-safe way during update With the new parallel update code, it is possible for multiple workers to try to create a hierarchy of directories at the same time. This is hard to trigger in general, but most likely during initial checkout. To deal with these races, we introduce a new ensuredirs function whose contract is to ensure that a directory hierarchy exists - it will ignore a failure that implies that the desired directory already exists.

Merge