identify: add template support

This is based on a patch proposed last year by Mathias De Maré[1], with a few
changes.

  - Tags and bookmarks are now formatted lists, for more flexible queries.
  - The templater is populated whether or not [-nibtB] is specified.  (Plain
    output is unchanged.)  This seems more consistent with other templated
    commands.
  - The 'id' property is a string, instead of a list.
  - The parents of 'wdir()' have their own list of attributes.

I left 'id' as a string because it seems very useful for generating version
info.  It's also a bit strange because the value and meaning changes depending
on whether or not --debug is passed (short vs full hash), whether the revision
is a merge or not (one hash or two, separated by a '+'), the working directory
or not (node vs p1node), and local or not (remote defaults to tip, and never has
'+').  The equivalent string built with {rev} seems much less useful, and I
couldn't think of a reasonable name, so I left it out.

The discussion seemed to be pointing towards having a list of nodes, with more
than one entry for a merge.  It seems simpler to give the nodes a name, and use
{node} for the actual commit probed, especially now that there is a virtual node
for 'wdir()'.

Yuya mentioned using fm.nested() in that thread, so I did for the parent nodes.
I'm not sure if the plan is to fill in all of the context attributes in these
items, or if these nested items should simply be made {p1node} and {p1rev}.

I used ':' as the tag separator for consistency with {tags} in the log
templater.  Likewise, bookmarks are separated by a space for consistency with
the corresponding log template.

[1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2016-August/087039.html

mercurial/commands.py

@@ -2667,7 +2667,7 b' def help_(ui, name=None, **opts):'
     ('b', 'branch', None, _('show branch')),
     ('t', 'tags', None, _('show tags')),
     ('B', 'bookmarks', None, _('show bookmarks')),
-    ] + remoteopts,
+    ] + remoteopts + formatteropts,
     _('[-nibtB] [-r REV] [SOURCE]'),
     optionalrepo=True)
 def identify(ui, repo, source=None, rev=None,
@@ -2726,6 +2726,9 b' def identify(ui, repo, source=None, rev='
         repo = peer.local()
         revs, checkout = hg.addbranchrevs(repo, peer, branches, None)
 
+    fm = ui.formatter('identify', opts)
+    fm.startitem()
+
     if not repo:
         if num or branch or tags:
             raise error.Abort(
@@ -2736,8 +2739,10 b' def identify(ui, repo, source=None, rev='
             rev = "tip"
 
         remoterev = peer.lookup(rev)
+        hexrev = hexfunc(remoterev)
         if default or id:
-            output = [hexfunc(remoterev)]
+            output = [hexrev]
+        fm.data(id=hexrev)
 
         def getbms():
             bms = []
@@ -2749,13 +2754,17 b' def identify(ui, repo, source=None, rev='
 
             return sorted(bms)
 
+        bms = getbms()
         if bookmarks:
-            output.extend(getbms())
+            output.extend(bms)
         elif default and not ui.quiet:
             # multiple bookmarks for a single parent separated by '/'
-            bm = '/'.join(getbms())
+            bm = '/'.join(bms)
             if bm:
                 output.append(bm)
+
+        fm.data(node=hex(remoterev))
+        fm.data(bookmarks=fm.formatlist(bms, name='bookmark'))
     else:
         ctx = scmutil.revsingle(repo, rev, None)
 
@@ -2767,19 +2776,32 b' def identify(ui, repo, source=None, rev='
                 taglist.extend(p.tags())
 
             changed = ""
-            if default or id or num:
-                if (any(repo.status())
-                    or any(ctx.sub(s).dirty() for s in ctx.substate)):
-                    changed = '+'
+            if (any(repo.status())
+                or any(ctx.sub(s).dirty() for s in ctx.substate)):
+                changed = '+'
+            fm.data(changed=changed)
+
+            hexoutput = [hexfunc(p.node()) for p in parents]
             if default or id:
-                output = ["%s%s" %
-                  ('+'.join([hexfunc(p.node()) for p in parents]), changed)]
+                output = ["%s%s" % ('+'.join(hexoutput), changed)]
+            fm.data(id="%s%s" % ('+'.join(hexoutput), changed))
+
             if num:
-                output.append("%s%s" %
-                  ('+'.join(["%d" % p.rev() for p in parents]), changed))
+                numoutput = ["%d" % p.rev() for p in parents]
+                output.append("%s%s" % ('+'.join(numoutput), changed))
+
+            for i, p in enumerate(parents):
+                fn = fm.nested('p%d' % (i + 1))
+                fn.startitem()
+                fn.data(rev=p.rev())
+                fn.data(node=p.hex())
+                fn.end()
         else:
+            hexoutput = hexfunc(ctx.node())
             if default or id:
-                output = [hexfunc(ctx.node())]
+                output = [hexoutput]
+            fm.data(id=hexoutput)
+
             if num:
                 output.append(pycompat.bytestr(ctx.rev()))
             taglist = ctx.tags()
@@ -2808,7 +2830,13 b' def identify(ui, repo, source=None, rev='
             if bookmarks:
                 output.extend(ctx.bookmarks())
 
-    ui.write("%s\n" % ' '.join(output))
+        fm.data(node=ctx.hex())
+        fm.data(branch=ctx.branch())
+        fm.data(tags=fm.formatlist(taglist, name='tag', sep=':'))
+        fm.data(bookmarks=fm.formatlist(ctx.bookmarks(), name='bookmark'))
+
+    fm.plain("%s\n" % ' '.join(output))
+    fm.end()
 
 @command('import|patch',
     [('p', 'strip', 1,

tests/test-completion.t

@@ -295,7 +295,7 b' Show all commands + options'
   grep: print0, all, text, follow, ignore-case, files-with-matches, line-number, rev, user, date, template, include, exclude
   heads: rev, topo, active, closed, style, template
   help: extension, command, keyword, system
-  identify: rev, num, id, branch, tags, bookmarks, ssh, remotecmd, insecure
+  identify: rev, num, id, branch, tags, bookmarks, ssh, remotecmd, insecure, template
   import: strip, base, edit, force, no-commit, bypass, partial, exact, prefix, import-branch, message, logfile, date, user, similarity
   incoming: force, newest-first, bundle, rev, bookmarks, branch, patch, git, limit, no-merges, stat, graph, style, template, ssh, remotecmd, insecure, subrepos
   locate: rev, print0, fullpath, include, exclude

tests/test-hook.t

@@ -95,7 +95,7 b' pretxncommit and commit hooks can see bo'
 test generic hooks
 
   $ hg id
-  pre-identify hook: HG_ARGS=id HG_HOOKNAME=pre-identify HG_HOOKTYPE=pre-identify HG_OPTS={'bookmarks': None, 'branch': None, 'id': None, 'insecure': None, 'num': None, 'remotecmd': '', 'rev': '', 'ssh': '', 'tags': None} HG_PATS=[]
+  pre-identify hook: HG_ARGS=id HG_HOOKNAME=pre-identify HG_HOOKTYPE=pre-identify HG_OPTS={'bookmarks': None, 'branch': None, 'id': None, 'insecure': None, 'num': None, 'remotecmd': '', 'rev': '', 'ssh': '', 'tags': None, 'template': ''} HG_PATS=[]
   abort: pre-identify hook exited with status 1
   [255]
   $ hg cat b

tests/test-identify.t

@@ -43,12 +43,36 b' with options'
   cb9a9f314b8b
   $ hg id -n -t -b -i
   cb9a9f314b8b 0 default tip
+  $ hg id -Tjson
+  [
+   {
+    "bookmarks": [],
+    "branch": "default",
+    "changed": "",
+    "id": "cb9a9f314b8b",
+    "node": "ffffffffffffffffffffffffffffffffffffffff",
+    "p1": [{"node": "cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b", "rev": 0}],
+    "tags": ["tip"]
+   }
+  ]
 
 with modifications
 
   $ echo b > a
   $ hg id -n -t -b -i
   cb9a9f314b8b+ 0+ default tip
+  $ hg id -Tjson
+  [
+   {
+    "bookmarks": [],
+    "branch": "default",
+    "changed": "+",
+    "id": "cb9a9f314b8b+",
+    "node": "ffffffffffffffffffffffffffffffffffffffff",
+    "p1": [{"node": "cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b", "rev": 0}],
+    "tags": ["tip"]
+   }
+  ]
 
 other local repo
 

tests/test-merge-default.t

@@ -49,6 +49,19 b' Should succeed:'
   $ hg merge 2
   0 files updated, 1 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
+  $ hg id -Tjson
+  [
+   {
+    "bookmarks": [],
+    "branch": "default",
+    "changed": "+",
+    "id": "f25cbe84d8b3+2d95304fed5d+",
+    "node": "ffffffffffffffffffffffffffffffffffffffff",
+    "p1": [{"node": "f25cbe84d8b320e298e7703f18a25a3959518c23", "rev": 4}],
+    "p2": [{"node": "2d95304fed5d89bc9d70b2a0d02f0d567469c3ab", "rev": 2}],
+    "tags": ["tip"]
+   }
+  ]
   $ hg commit -mm1
 
 Should succeed - 2 heads:
@@ -65,6 +78,17 b' Should succeed - 2 heads:'
   (branch merge, don't forget to commit)
   $ hg commit -mm2
 
+  $ hg id -r 1 -Tjson
+  [
+   {
+    "bookmarks": [],
+    "branch": "default",
+    "id": "1846eede8b68",
+    "node": "1846eede8b6886d8cc8a88c96a687b7fe8f3b9d1",
+    "tags": []
+   }
+  ]
+
 Should fail because at tip:
 
   $ hg merge