show: fix corrupt json output with no bookmarks

hgext/show.py

@@ -1,136 +1,140 b''
 # show.py - Extension implementing `hg show`
 #
 # Copyright 2017 Gregory Szorc <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 """unified command to show various repository information (EXPERIMENTAL)
 
 This extension provides the :hg:`show` command, which provides a central
 command for displaying commonly-accessed repository data and views of that
 data.
 """
 
 from __future__ import absolute_import
 
 from mercurial.i18n import _
 from mercurial import (
     cmdutil,
     commands,
     error,
+    formatter,
     pycompat,
     registrar,
 )
 
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'ships-with-hg-core'
 
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 
 class showcmdfunc(registrar._funcregistrarbase):
     """Register a function to be invoked for an `hg show <thing>`."""
 
     # Used by _formatdoc().
     _docformat = '%s -- %s'
 
     def _extrasetup(self, name, func, fmtopic=None):
         """Called with decorator arguments to register a show view.
 
         ``name`` is the sub-command name.
 
         ``func`` is the function being decorated.
 
         ``fmtopic`` is the topic in the style that will be rendered for
         this view.
         """
         func._fmtopic = fmtopic
 
 showview = showcmdfunc()
 
 @command('show', commands.formatteropts, _('VIEW'))
 def show(ui, repo, view=None, template=None):
     """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:
 
     """
     if ui.plain() and not template:
         hint = _('invoke with -T/--template to control output format')
         raise error.Abort(_('must specify a template in plain mode'), hint=hint)
 
     views = showview._table
 
     if not view:
         ui.pager('show')
         # TODO consider using formatter here so available views can be
         # rendered to custom format.
         ui.write(_('available views:\n'))
         ui.write('\n')
 
         for name, func in sorted(views.items()):
             ui.write(('%s\n') % func.__doc__)
 
         ui.write('\n')
         raise error.Abort(_('no view requested'),
                           hint=_('use "hg show VIEW" to choose a view'))
 
     # TODO use same logic as dispatch to perform prefix matching.
     if view not in views:
         raise error.Abort(_('unknown view: %s') % view,
                           hint=_('run "hg show" to see available views'))
 
     template = template or 'show'
     fmtopic = 'show%s' % views[view]._fmtopic
 
     ui.pager('show')
     with ui.formatter(fmtopic, {'template': template}) as fm:
         return views[view](ui, repo, fm)
 
 @showview('bookmarks', fmtopic='bookmarks')
 def showbookmarks(ui, repo, fm):
     """bookmarks and their associated changeset"""
     marks = repo._bookmarks
     if not len(marks):
-        # TODO json output is corrupted; consider using formatter
+        # This is a bit hacky. Ideally, templates would have a way to
+        # specify an empty output, but we shouldn't corrupt JSON while
+        # waiting for this functionality.
+        if not isinstance(fm, formatter.jsonformatter):
         ui.write(_('(no bookmarks set)\n'))
         return
 
     active = repo._activebookmark
     longestname = max(len(b) for b in marks)
     # TODO consider exposing longest shortest(node).
 
     for bm, node in sorted(marks.items()):
         fm.startitem()
         fm.context(ctx=repo[node])
         fm.write('bookmark', '%s', bm)
         fm.write('node', fm.hexfunc(node), fm.hexfunc(node))
         fm.data(active=bm == active,
                 longestbookmarklen=longestname)
 
 # Adjust the docstring of the show command so it shows all registered views.
 # This is a bit hacky because it runs at the end of module load. When moved
 # into core or when another extension wants to provide a view, we'll need
 # to do this more robustly.
 # TODO make this more robust.
 longest = max(map(len, showview._table.keys()))
 for key in sorted(showview._table.keys()):
     cmdtable['show'][0].__doc__ += pycompat.sysstr(' %s   %s\n' % (
         key.ljust(longest), showview._table[key]._origdoc))

tests/test-show.t

@@ -1,117 +1,125 b''
   $ 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
   
   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
   
   (use 'hg help -e show' to show help for the show extension)
   
   options:
   
   (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    7b570
     book1                b757f
 
 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"
    },
    {
     "active": false,
     "bookmark": "book1",
     "longestbookmarklen": 17,
     "node": "b757f780b8ffd71267c6ccb32e0882d9d32a8cc0"
    }
   ]
 
+JSON works with no bookmarks
+
+  $ hg book -d a-longer-bookmark
+  $ hg book -d book1
+  $ hg show bookmarks -T json
+  [
+  ]
+
   $ cd ..