phases: remove trace of addednodes in the 'phase-heads' handling updatephases have no use of the 'addednodes' parameter since 50243c975fc2. However caller are still passing it for nothing, remove the parameter and remove computing of the added nodes in caller.

phases: test phases tracking at the transaction level Now that we have all tracking in place, the data in `tr.changes['phases']` dictionary should be correct and we should test it. It is a bit late in the cycle to discuss to add any public API (eg: hooks) that expose the data to the user, so we just add a small test extension displaying the data. It is enabled for the phases tests. New output have been manually checked for consistency.

phases: track phase changes from 'retractboundary' We adds new computation to find and record the revision affected by the boundary retraction. This add more complication to the function but this seems fine since it is only used in a couple of rare and explicit cases (`hg phase --force` and `hg qimport`). Having strong tracking of phase changes is worth the effort.

phases: detect when boundaries has been actually retracted It is useful to detect noop and avoid expensive operations in this case. We return the information to inform the caller of a possible update. Top level function might need to react to the phase update (eg: invalidating some caches, tracking phase change).

phases: rework phase movement code in 'cg.apply' to use 'registernew' We rework the code to call 'registernew' before any other phase advancement. This make 'changegroup.apply' register correct phase movement for the added and bundled nodes.

convert: use the new 'phase.registernew' function

localrepo: use the 'registernew' function to set the phase of new commit

phases: add a 'registernew' method to set new phases This new function will be used by code that adds new changesets. It ajusts the phase boundary to make sure added changesets are at least in their target phase (they end up in an higher phase if their parents are in a higher phase). Having a dedicated function also simplify the phases tracking. All the new nodes are passed as argument, so we know that all of them needs to have their new phase registered. We also know that no other nodes will be affected, so no extra computation are needed. This function differ from 'retractboundary' where some nodes might change phase while some other might not. It can also affect nodes not passed as parameters. These simplification also apply to the computation itself. For now we use '_retractboundary' there by convenience, but we may introduces simpler code later. While registering new revisions, we still need to check the actual phases of the added node because it might be higher than the target phase (eg: target is draft but parent is secret). We will migrate users over the next changesets.

phases: extract the core of boundary retraction in '_retractboundary' At the moment the 'retractboundary' function is called for multiple reasons: First, actually retracting boundaries. There are only two cases for theses: 'hg phase --force' and 'hg qimport'. This will need extra graph computation to retrieve the phase changes. Second, setting the phases of newly added changesets. In this case we already know all the affected nodes and we just needs to register different information (old phase is None). Third, when reducing the set of roots when advancing phase. The phase are already properly tracked so we do not needs anything else in this case. To deal with this difference in phase tracking, we extract the core logic into a private method that all three cases can use.

phases: track phase movements in 'advanceboundary' Makes advanceboundary record the phase movement of affected revisions in tr.changes['phases']. The tracking is not usable yet because the 'retractboundary' function can also affect phases. We'll improve that in the coming changesets.