tests/test-show.t

files: speed up `hg files` when no flags change display

It's not the first time I see slowness from this command slow down
tools built on top of hg.

The majority of the time is spent merely printing the result before
this change, which is clearly not how it should be (especially since
the computation of the result also looks slow).

Running `hg files` in mozilla-central:

parent revision: 1,260s
this commit: 0,683s
this commit without batching ui.write: 0,931s
this commit replacing the body of the loop with `pass`: 0,566s

This looks like a prime candidate for a rust fast path, but until
then, it seems reasonable to optimize the python.

Differential Revision: https://phab.mercurial-scm.org/D8586

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > show =
  > EOF

No arguments shows available views

  $ hg init empty
  $ cd empty
  $ hg show
  available views:
  
  bookmarks -- bookmarks and their associated changeset
  stack -- current line of work
  work -- changesets that aren't finished
  
  abort: no view requested
  (use "hg show VIEW" to choose a view)
  [255]

`hg help show` prints available views

  $ hg help show
  hg show VIEW
  
  show various repository information
  
      A requested view of repository data is displayed.
  
      If no view is requested, the list of available views is shown and the
      command aborts.
  
      Note:
         There are no backwards compatibility guarantees for the output of this
         command. Output may change in any future Mercurial release.
  
         Consumers wanting stable command output should specify a template via
         "-T/--template".
  
      List of available views:
  
      bookmarks   bookmarks and their associated changeset
  
      stack       current line of work
  
      work        changesets that aren't finished
  
  (use 'hg help -e show' to show help for the show extension)
  
  options:
  
   -T --template TEMPLATE display with template
  
  (some details hidden, use --verbose to show complete help)

Unknown view prints error

  $ hg show badview
  abort: unknown view: badview
  (run "hg show" to see available views)
  [255]

HGPLAIN results in abort

  $ HGPLAIN=1 hg show bookmarks
  abort: must specify a template in plain mode
  (invoke with -T/--template to control output format)
  [255]

But not if a template is specified

  $ HGPLAIN=1 hg show bookmarks -T '{bookmark}\n'
  (no bookmarks set)

  $ cd ..

bookmarks view with no bookmarks prints empty message

  $ hg init books
  $ cd books
  $ touch f0
  $ hg -q commit -A -m initial

  $ hg show bookmarks
  (no bookmarks set)

bookmarks view shows bookmarks in an aligned table

  $ echo book1 > f0
  $ hg commit -m 'commit for book1'
  $ echo book2 > f0
  $ hg commit -m 'commit for book2'

  $ hg bookmark -r 1 book1
  $ hg bookmark a-longer-bookmark

  $ hg show bookmarks
  * a-longer-bookmark    7b57
    book1                b757

A custom bookmarks template works

  $ hg show bookmarks -T '{node} {bookmark} {active}\n'
  7b5709ab64cbc34da9b4367b64afff47f2c4ee83 a-longer-bookmark True
  b757f780b8ffd71267c6ccb32e0882d9d32a8cc0 book1 False

bookmarks JSON works

  $ hg show bookmarks -T json
  [
   {
    "active": true,
    "bookmark": "a-longer-bookmark",
    "longestbookmarklen": 17,
    "node": "7b5709ab64cbc34da9b4367b64afff47f2c4ee83",
    "nodelen": 4
   },
   {
    "active": false,
    "bookmark": "book1",
    "longestbookmarklen": 17,
    "node": "b757f780b8ffd71267c6ccb32e0882d9d32a8cc0",
    "nodelen": 4
   }
  ]

JSON works with no bookmarks

  $ hg book -d a-longer-bookmark
  $ hg book -d book1
  $ hg show bookmarks -T json
  [
  ]

commands.show.aliasprefix aliases values to `show <view>`

  $ hg --config commands.show.aliasprefix=s sbookmarks
  (no bookmarks set)

  $ hg --config commands.show.aliasprefix=sh shwork
  @  7b57 commit for book2
  o  b757 commit for book1
  o  ba59 initial

  $ hg --config commands.show.aliasprefix='s sh' swork
  @  7b57 commit for book2
  o  b757 commit for book1
  o  ba59 initial

  $ hg --config commands.show.aliasprefix='s sh' shwork
  @  7b57 commit for book2
  o  b757 commit for book1
  o  ba59 initial

The aliases don't appear in `hg config`

  $ hg --config commands.show.aliasprefix=s config alias
  [1]

Doesn't overwrite existing alias

  $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s swork
  changeset:   2:7b5709ab64cb
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit for book2
  

  $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s config alias
  alias.swork=log -r .

  $ cd ..