phases: use a Struct object for binary encoding and decoding We will move the binary encoding and decoding code to 'phases.py' in order to make it easier to reuse. First, let's cleanup it a bit.

discovery: avoid dropping remote heads hidden locally An extra post processing was added to recognize remote heads that are hidden locally as "common" instead of "unknown". However, this processing was removing such hidden heads from the remote heads sets. It had no impact because we used to pull phase information from all remote heads. This series will replace the phase pulling operation to a more efficient process but requires the unmodified pulled set information.

test-patchbomb: use mocktime The test was using system time for displaying ETAs, which could be flaky if the sysload is high. This patch extracts mocktime.py from test-progress.t to make sure test-patchbomb.t is unaffected by system time. Differential Revision: https://phab.mercurial-scm.org/D844

test-patchbomb: fix the test With the experimental config `progress.estimate` removed, the progress output in `test-patchbomb.t` has a minor change: it shows ETA since the beginning. (This could be folded into f428c3)

progress: make ETA only consider progress made in the last minute This patch limits the estimate time interval to roughly the last minute (configurable by `estimateinterval`) to be more practical. See the test change for why this is better. .. feature:: Estimated time is more accurate with non-linear progress Differential Revision: https://phab.mercurial-scm.org/D820

progress: remove progress.estimate config It was introduced by 98e4d39 ("progress: add speed format" 2011-5-9) and was intended to hide ETA information for the first few seconds. Later 5d261fd ("progress: add a changedelay to prevent parallel topics from flapping (issue2698)" 2011-6-23) introduced `changedelay` config which hides the entire progress bar for the first few seconds. So `progress.estimate` seems somehow duplicated feature-wise. Since it's experimental and duplicated, let's just remove it. This makes the next patch simpler - it no longer needs to make sure `starttimes` is the real start time. Differential Revision: https://phab.mercurial-scm.org/D828

progress: demonstrate non-linear progress has a bad ETA experience Previously, the ETA and speed assumes the progress is linear. Often, due to network or other issues, it could be fast for the most time, and suddenly slow down: [====================================================> ] \___________________________________________/\______/ very fast suddenly much slower This patch adds a test demonstrating the ETA could be way off in those cases. Differential Revision: https://phab.mercurial-scm.org/D819

copytrace: add a a new config to limit the number of drafts in heuristics The heuristics options tries to the default full copytracing algorithm if both the source and destination branches contains of non-public changesets only. But this can be slow in cases when we have a lot of drafts. This patch adds a new config option experimental.copytrace.sourcecommitlimit which defaults to 100. This value will be the limit of number of drafts from c1 to base. Incase there are more changesets even though they are draft, the heuristics algorithm will be used. Differential Revision: https://phab.mercurial-scm.org/D763