[PATCH 3 of 3] commands: add template support for config

[Mathias De Maré]

# HG changeset patch
# User Mathias De Maré <mathias.demare at gmail.com>
# Date 1472447235 -7200
#      Mon Aug 29 07:07:15 2016 +0200
# Node ID dd7b8ff51af615e1a44d32b103d23e8cd34d5dd9
# Parent  e348c87b33d73a590bee53b74def915b1ce8c6fe
commands: add template support for config

V2:
- Limit escaping to plain formatting only
- Use the formatter consistently (no more ui.debug)
- Always include 'name' and 'value'

Example output:
[
 {
  "name": "ui.username",
  "source": "/home/mathias/.hgrc:2",
  "value": "Mathias De Maré <mathias.demare at gmail.com>"
 }
]

diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -1788,7 +1788,7 @@
     [('u', 'untrusted', None, _('show untrusted configuration options')),
      ('e', 'edit', None, _('edit user config')),
      ('l', 'local', None, _('edit repository config')),
-     ('g', 'global', None, _('edit global config'))],
+     ('g', 'global', None, _('edit global config'))] + formatteropts,
     _('[-u] [NAME]...'),
     optionalrepo=True)
 def config(ui, repo, *values, **opts):
@@ -1849,8 +1849,10 @@
                   onerr=error.Abort, errprefix=_("edit failed"))
         return
 
-    for f in scmutil.rcpath():
-        ui.debug('read config from: %s\n' % f)
+    fm = ui.formatter('config', opts)
+    if ui.debugflag:
+        for f in scmutil.rcpath():
+            fm.plain('read config from: %s\n' % f)
     untrusted = bool(opts.get('untrusted'))
     if values:
         sections = [v for v in values if '.' not in v]
@@ -1859,25 +1861,31 @@
             raise error.Abort(_('only one config item permitted'))
     matched = False
     for section, name, value in ui.walkconfig(untrusted=untrusted):
-        value = str(value).replace('\n', '\\n')
-        sectname = section + '.' + name
+        if fm.isplain():
+            value = str(value).replace('\n', '\\n')
+        entryname = section + '.' + name
         if values:
             for v in values:
                 if v == section:
-                    ui.debug('%s: ' %
+                    fm.startitem()
+                    fm.condwrite(ui.debugflag, 'source', '%s: ',
                              ui.configsource(section, name, untrusted))
-                    ui.write('%s=%s\n' % (sectname, value))
+                    fm.write('name value', '%s=%s\n', entryname, value)
                     matched = True
-                elif v == sectname:
-                    ui.debug('%s: ' %
+                elif v == entryname:
+                    fm.startitem()
+                    fm.condwrite(ui.debugflag, 'source', '%s: ',
                              ui.configsource(section, name, untrusted))
-                    ui.write(value, '\n')
+                    fm.write('value', '%s\n', value)
+                    fm.data(name=entryname)
                     matched = True
         else:
-            ui.debug('%s: ' %
+            fm.startitem()
+            fm.condwrite(ui.debugflag, 'source', '%s: ',
                      ui.configsource(section, name, untrusted))
-            ui.write('%s=%s\n' % (sectname, value))
+            fm.write('name value', '%s=%s\n', entryname, value)
             matched = True
+    fm.end()
     if matched:
         return 0
     return 1
diff --git a/tests/test-completion.t b/tests/test-completion.t
--- a/tests/test-completion.t
+++ b/tests/test-completion.t
@@ -232,7 +232,7 @@
   branches: active, closed, template
   bundle: force, rev, branch, base, all, type, ssh, remotecmd, insecure
   cat: output, rev, decode, include, exclude
-  config: untrusted, edit, local, global
+  config: untrusted, edit, local, global, template
   copy: after, force, include, exclude, dry-run
   debugancestor: 
   debugapplystreamclonebundle: 
diff --git a/tests/test-config.t b/tests/test-config.t
--- a/tests/test-config.t
+++ b/tests/test-config.t
@@ -54,6 +54,20 @@
   Section.KeY=Case Sensitive
   Section.key=lower case
 
+  $ hg showconfig Section -Tjson
+  [
+   {
+    "name": "Section.KeY",
+    "source": "*.hgrc:16", (glob)
+    "value": "Case Sensitive"
+   },
+   {
+    "name": "Section.key",
+    "source": "*.hgrc:17", (glob)
+    "value": "lower case"
+   }
+  ]
+
 Test "%unset"
 
   $ cat >> $HGRCPATH <<EOF