tests/test-mq-qpush-exact.t

show: implement "stack" view

People often want to know what they are working on *now*. As part of
this, they also commonly want to know how that work is related to other
changesets in the repo so they can perform common actions like rebase,
histedit, and merge.

`hg show work` made headway into this space. However, it is geared
towards a complete repo view as opposed to just the current line of
work. If you have a lot of in-flight work or the repo has many heads,
the output can be overwhelming. The closest thing Mercurial has to
"show me the current thing I'm working on" that doesn't require custom
revsets is `hg qseries`. And this requires MQ, which completely changes
workflows and repository behavior and has horrible performance on large
repos. But as sub-optimal as MQ is, it does some things right, such as
expose a model of the repo that is easy for people to reason about.
This simplicity is why I think a lot of people prefer to use MQ, despite
its shortcomings.

One common development workflow is to author a series of linear
changesets, using bookmarks, branches, anonymous heads, or even topics
(3rd party extension). I'll call this a "stack." You periodically
rewrite history in place (using `hg histedit`) and reparent the stack
against newer changesets (using `hg rebase`). This workflow can be
difficult because there is no obvious way to quickly see the current
"stack" nor its relation to other changesets. Figuring out arguments to
`hg rebase` can be difficult and may require highlighting and pasting
multiple changeset nodes to construct a command.

The goal of this commit is to make stack based workflows simpler
by exposing a view of the current stack and its relationship to
other releant changesets, notably the parent of the base changeset
in the stack and newer heads that the stack could be rebased or merged
into.

Introduced is the `hg show stack` view. Essentially, it finds all
mutable changesets from the working directory revision in both
directions, stopping at a merge or branch point. This limits the
revisions to a DAG linear range.

The stack is rendered as a concise list of changesets. Alongside the
stack is a visualization of the DAG, similar to `hg log -G`.

Newer public heads from the branch point of the stack are rendered
above the stack. The presence of these heads helps people understand
the DAG model and the relationship between the stack and changes made
since the branch point of that stack. If the "rebase" command is
available, a `hg rebase` command is printed for each head so a user
can perform a simple copy and paste to perform a rebase.

This view is alpha quality. There are tons of TODOs documented
inline. But I think it is good enough for a first iteration.

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

make a test repository that looks like this:

o    2:28bc7b1afd6a
|
| @  1:d7fe2034f71b
|/
o    0/62ecad8b70e5

  $ hg init r0
  $ cd r0
  $ touch f0
  $ hg ci -m0 -Aq
  $ touch f1
  $ hg ci -m1 -Aq

  $ hg update 0 -q
  $ touch f2
  $ hg ci -m2 -Aq
  $ hg update 1 -q

make some patches with a parent: 1:d7fe2034f71b -> p0 -> p1

  $ echo cp0 >> fp0
  $ hg add fp0
  $ hg ci -m p0 -d "0 0"
  $ hg export -r. > p0
  $ hg strip -qn .
  $ hg qimport p0
  adding p0 to series file
  $ hg qpush
  applying p0
  now at: p0

  $ echo cp1 >> fp1
  $ hg add fp1
  $ hg qnew p1 -d "0 0"

  $ hg qpop -aq
  patch queue now empty

qpush --exact when at the parent

  $ hg update 1 -q
  $ hg qpush -e
  applying p0
  now at: p0
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

  $ hg qpush -e p0
  applying p0
  now at: p0
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

  $ hg qpush -e p1
  applying p0
  applying p1
  now at: p1
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

qpush --exact when at another rev

  $ hg update 0 -q
  $ hg qpush -e
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  applying p0
  now at: p0
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

  $ hg update 0 -q
  $ hg qpush -e p0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  applying p0
  now at: p0
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

  $ hg update 0 -q
  $ hg qpush -e p1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  applying p0
  applying p1
  now at: p1
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

  $ hg update 0 -q
  $ hg qpush -ea
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  applying p0
  applying p1
  now at: p1
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

qpush --exact while crossing branches

  $ hg update 2 -q
  $ hg qpush -e
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  applying p0
  now at: p0
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

  $ hg update 2 -q
  $ hg qpush -e p0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  applying p0
  now at: p0
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

  $ hg update 2 -q
  $ hg qpush -e p1
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  applying p0
  applying p1
  now at: p1
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

  $ hg update 2 -q
  $ hg qpush -ea
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  applying p0
  applying p1
  now at: p1
  $ hg parents -qr qbase
  1:d7fe2034f71b
  $ hg qpop -aq
  patch queue now empty

qpush --exact --force with changes to an unpatched file

  $ hg update 1 -q
  $ echo c0 >> f0
  $ hg qpush -e
  abort: local changes found
  [255]
  $ hg qpush -ef
  applying p0
  now at: p0
  $ cat f0
  c0
  $ rm f0
  $ touch f0
  $ hg qpop -aq
  patch queue now empty

  $ hg update 1 -q
  $ echo c0 >> f0
  $ hg qpush -e p1
  abort: local changes found
  [255]
  $ hg qpush -e p1 -f
  applying p0
  applying p1
  now at: p1
  $ cat f0
  c0
  $ rm f0
  $ touch f0
  $ hg qpop -aq
  patch queue now empty

qpush --exact --force with changes to a patched file

  $ hg update 1 -q
  $ echo cp0-bad >> fp0
  $ hg add fp0
  $ hg qpush -e
  abort: local changes found
  [255]
  $ hg qpush -ef
  applying p0
  file fp0 already exists
  1 out of 1 hunks FAILED -- saving rejects to file fp0.rej
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh p0
  [2]
  $ cat fp0
  cp0-bad
  $ cat fp0.rej
  --- fp0
  +++ fp0
  @@ -0,0 +1,1 @@
  +cp0
  $ hg qpop -aqf
  patch queue now empty
  $ rm fp0
  $ rm fp0.rej

  $ hg update 1 -q
  $ echo cp1-bad >> fp1
  $ hg add fp1
  $ hg qpush -e p1
  abort: local changes found
  [255]
  $ hg qpush -e p1 -f
  applying p0
  applying p1
  file fp1 already exists
  1 out of 1 hunks FAILED -- saving rejects to file fp1.rej
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh p1
  [2]
  $ cat fp1
  cp1-bad
  $ cat fp1.rej
  --- fp1
  +++ fp1
  @@ -0,0 +1,1 @@
  +cp1
  $ hg qpop -aqf
  patch queue now empty
  $ hg forget fp1
  $ rm fp1
  $ rm fp1.rej

qpush --exact when already at a patch

  $ hg update 1
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg qpush -e p0
  applying p0
  now at: p0
  $ hg qpush -e p1
  abort: cannot push --exact with applied patches
  [255]
  $ hg qpop -aq
  patch queue now empty

qpush --exact --move should fail

  $ hg qpush -e --move p1
  abort: cannot use --exact and --move together
  [255]

qpush --exact a patch without a parent recorded

  $ hg qpush -q
  now at: p0
  $ grep -v '# Parent' .hg/patches/p0 > p0.new
  $ mv p0.new .hg/patches/p0
  $ hg qpop -aq
  patch queue now empty
  $ hg qpush -e
  abort: p0 does not have a parent recorded
  [255]
  $ hg qpush -e p0
  abort: p0 does not have a parent recorded
  [255]
  $ hg qpush -e p1
  abort: p0 does not have a parent recorded
  [255]
  $ hg qpush -ea
  abort: p0 does not have a parent recorded
  [255]

  $ cd ..