CHANGELOG: add an entry about next and prev being interactive

prev: show changeset hash in --dry-run instead of rev numbers rev numbers can change, so it's better to show changeset hash.

prev: prompt user to choose parent in case of multiple parents This patch adds functionality to `hg prev` to prompt user to choose one parent to update when multiple parents exist. Surprisingly there were no tests for this case before this patch, I added one with this patch.

next: cleanup logic around return by returning early In the cmdnext function, there are some conditionals which returns early and some which sets a result value to be returned later. Let's return from all the conditionals early. There are if, elif and else involved, so it's sure we will end up in one of the conditional, each conditional will return, so it's guranteed that we are returning the correct value and returning everytime.

next: prompt user to choose child in ambiguity in `hg next --evolve` This patch makes `hg next --evolve` prompt user to choose a child to evolve and update when multiple of them exists. This is improvement over previous behavior where we used to error out saying ambiguous next unstable changeset and told user to manually use `hg evolve -r rev`. While writing this patch, I am personally very happy to have this feature as I have encountered this stage many times and I wanted `next --evolve` to take care of that. It uses the revselectionprompt thing added in earlier patches.

next: move logic to evolve the children to it's own function This patch moves the logic which evolves the children and updates to it in `hg next --evolve` to it's own function as we want to use that again.

next: prompt user to choose a children in case of ambiguity This patch adds functionality to prompt user and ask the children to which next should move to incase of multiple childrens. This is a very nice UI because otherwise user has to lookup changeset hash, and then manually do `hg update` to that. In this case we show hash and description so user can choose which one to update easily. It is using the interactive revision choosing functionality added in a previous patch.

next: show changeset hash in `--dry-run` instead of rev numbers Rev numbers can change, hence we should show rev hash instead of rev numbers in dry-run.

evolve: make sure we consider all cases in if-else The part of code which is touched decides on evolution of merge changeset. We need proper handling of each case there, so before adding logic, let's add conditional for each case so that upcoming patches are easy to understand.

tests: add more cases about stabilization of an orphaned merge commit This patch adds three more cases related to stabilization of orphaned merge commits.

evolve: fix missing negation Spotted by Pulkit Goyal.

evolve: clarify message for ambiguous destination from split Message is a bit long, but should be less scary.

evolve: prompt user to select destination for stabilization in case of split This patch adds functionality to prompt user to select a revision when there exists multiple stabilization destination because of split on multiple branches. Test are also added for the feature. I am not sure whether this is the best message which we can show, if people have suggestions I will like to improve the messages shown in prompt.

tests: remove some tests which are moved to dedicated files The tests in test-unstable.t files are now moved to their dedicated file with all the cases to that in that file. Let's delete them from here.

next: factor out the logic to update to changeset in another function This patch moves the logic to update to children changeset during `hg next` in a separate function because we want to re-use the logic when we will prompt user to choose a changeset in case of multiple childrens.

utility: add a function to prompt user to choose a revision This patch adds a utility function to interactively prompt user to choose a revision to proceed in cases when there are multiple revisions which are candidates. The function will be used in `hg evolve`, `hg next`, `hg prev` etc. If user feedback will be good, I plan to move it to core and use it at more possible places.

tests: add a test about evolve stabilizing orphan caused by splits There are some similar tests lying around in the test suite but they are not well arranged. I wanted the test suite to be a goto reference for all the behaviors till the time we get all of them documented.

test: fix output after rev-branch-cache has been merged Mercurial core 2090044a288d added a new revbranchcache part which changed some exchange-related outputs. Glob them to ease merging with old Mercurial versions branches.

cleanup: remove duplicate import of "obsolete"

previous: fix behavior on obsolete cset when topic is involved (issue5708) This patch fixes the behavior of `hg previous` when done on an obsolete changeset having a successor of different topic. The underlying code is bit messed up, I wanted to split the topic handling to topic extension but I have postponed it to next bug.

previous: add test case when it's broken on obsolete cset This patch adds couple of tests showing `hg previous` is broken on obsolete changeset when the successor has different topic. Upcoming patch will fix this.

prev: fix the breakage of `hg previous` from obsolete cset This patch fix the breakage of `hg prev` from obsolete changeset when topic is involved. We get the topicidx of it's succesor and proceed.

prev: add a test case which shows traceback when doing prev on obsolete cset This patch adds a test which shows how `hg prev` is borken when called from a obsolete changeset and there is an active topic. The next patch will fix that.

tests: add more tests related to stabilization of orphaned merge commit This patch more tests related to stabilization of orphaned merge commit. Stabilization of a merge changeset with both the parents is not supported right now and prints a message on how to do that. Maybe we should do that internally as a part of `hg evolve` but I need to think about this.

evolve: fix stabilization of orphan merge changesets in case of conflicts As demonstrated by tests added in previous patch, if one of the parent of a merge changeset has a new version and merge changeset gets, running `hg evolve` to stabilize that if results in conflicts will lead to lose of other parent of that merge changeset when we resolve conflicts and do `hg evolve --continue`. This patch fixes the behavior, by checking whether we are continuing evolving a merge changeset and if yes, setting the dirstate parents according to that.

tests: add a test file of resolving orphaness of merge changesets This patch adds a new test file named test-evolve-orphan-merge.t which contains test cases when `hg evolve` try to stabilize a merge changeset which was orphan. This file contains 20-30% of all the cases as we have got something to fix before we add tests for rest of the cases. Going by this approach will make sure we don't live unfixed cases in the test file and the test files does not become a pile of hacks which are used to get in state when we fix the bugs.

grab: gracefully handle the case when we try to grab parent of wdir Before this patch, we go all the way down to obsmarker creation logic and gets an error saying that changeset cannot obsolete itself. We should be more smart here and error out early saying we cannot grab that changeset.

grab: move the initialization of pctx variable outside of if-else The pctx variable is used outside of the if-else but it was initialized under the conditional statements. Added test for the case when the initialization inside the if-else broke `hg grab --continue`.