dirstate: add a `update_file` function This function is the other side of the `set_tracked`/`set_untracked` API revamp. It is to be used when the dirstate is changing its parents during and update or a merge. It states all the information we know about the file so that the dirstate can update its internal data. Unlike the `set_tracked`/`set_untracked` it has not regards for the information previously tracked in the tristate. Differential Revision: https://phab.mercurial-scm.org/D11075

resolve: use the `parentchange` context manager to apply merge action In an ideal world, we would not have to do that. However, we are miles away from being ready to not have to do it. So we add this context manager alongside a long comment. This will help use to get to the point were have two distinct API with strict rules about when to call them. Differential Revision: https://phab.mercurial-scm.org/D11074

sparse: adjust the temporary includes within a `parentchange` context This is related to dirstate adjustment. Differential Revision: https://phab.mercurial-scm.org/D11033

amend: adjust the dirstate within a `parentchange` context The adjustment in the direct consequence of the amend and the associated parents change. Differential Revision: https://phab.mercurial-scm.org/D11032

dirstate: use the right internal API in a test script The goal of the script it to perform arbitrary internal operation to create incorrect state, so lets make it clear. Differential Revision: https://phab.mercurial-scm.org/D11031

sparse: clear rules in the context of a `parentchanges` context This is the same logic as the change we did for narrow. Differential Revision: https://phab.mercurial-scm.org/D11029

sparse: make sure we adjust the dirstate at the same time as the parent This is more correct and help our API split. Differential Revision: https://phab.mercurial-scm.org/D11028

narrow: update narrow spec within a dirstate.parentchange context Even if the parents does not changes, the parents' content we consider is changed. So this seems legitimate. Differential Revision: https://phab.mercurial-scm.org/D11027

revert: use `set_untracked` instead of `drop` when applicable This is the new shiny API. Differential Revision: https://phab.mercurial-scm.org/D11026

revert: use `set_untracked` when performing a revert This is the new shiny API. Differential Revision: https://phab.mercurial-scm.org/D11022

mq: use `set_untracked` in `qrename` This is the new shiny API. Differential Revision: https://phab.mercurial-scm.org/D11021

context: use `dirstate.set_untracked` in `context.forget` This is the new shiny API. Differential Revision: https://phab.mercurial-scm.org/D11020

dirstate: add a `set_untracked` method for "hg remove"-like usage This is a step further toward clarifying the semantic of various dirstate call. See the justification for adding `set_tracked` for details. Differential Revision: https://phab.mercurial-scm.org/D11019

mq: use `set_tracked` in `qrename` This is the new shiny API. Differential Revision: https://phab.mercurial-scm.org/D11018

mq: update the dirstate and its parent within a `parentchange` context This is more correct, and move our plan of separated API for different dirstate usage forward. note: maybe the `parentchange` context manager should replace the dirstateguard entirely ? (in this case we should probably deprecated dirstateguard). Differential Revision: https://phab.mercurial-scm.org/D11017

context: use `dirstate.set_tracked` for `revert` This is the new shiny API. Differential Revision: https://phab.mercurial-scm.org/D11016

context: use `dirstate.set_tracked` in context.copy This is the new shiny API. Differential Revision: https://phab.mercurial-scm.org/D11015

context: use `dirstate.set_tracked` in `context.add` This is the new shiny API. Differential Revision: https://phab.mercurial-scm.org/D11014

dirstate: add a `set_tracked` method for "hg add"-like usage This is a step further toward clarifying the semantic of various dirstate call. Having a dedicated function comes with a couple of benefits: 1) we can move duplicated logic about how to handle the previous state within the dirstate. Since we are sure this is always called in the same situation, we can implement that logic once in the dirstate. 2) having a dedicated method for this case unlock also having a dedicated method for the other case and recording more information at that time. All this leading having more code within the dirstate and higher level API that are less error prone. Differential Revision: https://phab.mercurial-scm.org/D11013

dirstate: add a function to update tracking status while "moving" parents The `scmutil.dirstateparent` is moving the dirstate parent without touching the working copy. It is used by history-rewriting operations like amending of folding. The function was directly doing the "low level" computation and dirstate change. All that logic belong to the dirstate and should be moved there. For this purpose we introduce a new function that does just that and use it. Differential Revision: https://phab.mercurial-scm.org/D11012

dirstate: introduce an internal `_drop` method We want to split current user of `dirstate.drop` between `hg rm`-like cases and update of the dirstate coming from update/merge. To do this we will introduce new API. The first step is to introduces an internal function that these new API migh use (or not use) to distinct between the migrated users and the others. Differential Revision: https://phab.mercurial-scm.org/D11023

dirstate: introduce an internal `_remove` method We want to split current user of `dirstate.remove` between `hg rm`-like cases and update of the dirstate coming from update/merge. To do this we will introduce new API. The first step is to introduces an internal function that these new API migh use (or not use) to distinct between the migrated users and the others. Differential Revision: https://phab.mercurial-scm.org/D11011

dirstate: introduce an internal `_add` method We want to split current user of `dirstate.add` between `hg add`-like cases and update of the dirstate coming from update/merge. To do this we will introduce new API. The first step is to introduces an internal function that these new API migh use (or not use) to distinct between the migrated users and the others. Differential Revision: https://phab.mercurial-scm.org/D11010

run-tests: rely on an actual executable in PATH instead of alias for `hg` The alias approach is poorly inherited by other process that the test might spawn. To solve this we use the same approach as for `python`/`python3` we write an executable file explicitly. Doing this fixes `which hg` invocation that now returns the same location as `hg`. Using chg server side has some minor effect on some stdout/stderr ordering when using `chg` as the server too. Differential Revision: https://phab.mercurial-scm.org/D11053