cmdutil: use '[committemplate]' section like as map file for style definition

Before this patch, each template definitions for 'changeset*' in
'[committemplate]' section have to be written fully from scratch,
even though many parts of them may be common.

This patch uses '[committemplate]' section like as the map file for
the style definition. All items other than 'changeset' can be referred
from others.

This can reduce total cost of template customization in
 '[committemplate]' section.

When the commit template other than '[committemplate] changeset'
is chosen by 'editform', putting '[committemplate] changeset'
value into the cache of the templater causes unexpected result,
because the templater stores the specified (= chosen) template
definition into own cache as 'changeset' at construction time.

This is the reason why '[committemplate] changeset' can't be referred
from others.

mercurial/cmdutil.py

@@ -2228,6 +2228,10 b' def buildcommittemplate(repo, ctx, subs,'
     except SyntaxError, inst:
         raise util.Abort(inst.args[0])
 
+    for k, v in repo.ui.configitems('committemplate'):
+        if k != 'changeset':
+            t.t.cache[k] = v
+
     if not extramsg:
         extramsg = '' # ensure that extramsg is string
 

mercurial/help/config.txt

@@ -419,6 +419,17 b' For example, ``changeset.tag.remove`` cu'
 only for :hg:`tag --remove`, but ``changeset.tag`` customizes the
 commit message for :hg:`tag` regardless of ``--remove`` option.
 
+In this section, items other than ``changeset`` can be referred from
+others. For example, the configuration to list committed files up
+below can be referred as ``{listupfiles}``::
+
+    [committemplate]
+    listupfiles = {file_adds %
+       "HG: added {file}\n"     }{file_mods %
+       "HG: changed {file}\n"   }{file_dels %
+       "HG: removed {file}\n"   }{if(files, "",
+       "HG: no files changed\n")}
+
 ``decode/encode``
 -----------------
 

tests/test-mq-qrefresh-replace-log-message.t

@@ -32,17 +32,19 b" template keyword 'extramsg' work well)"
 
   $ cat >> .hg/hgrc <<EOF
   > [committemplate]
+  > listupfiles = {file_adds %
+  >    "HG: added {file}\n"     }{file_mods %
+  >    "HG: changed {file}\n"   }{file_dels %
+  >    "HG: removed {file}\n"   }{if(files, "",
+  >    "HG: no files changed\n")}
+  > 
   > changeset = HG: this is customized commit template
   >     {desc}\n\n
   >     HG: Enter commit message.  Lines beginning with 'HG:' are removed.
   >     HG: {extramsg}
   >     HG: --
   >     HG: user: {author}
-  >     HG: branch '{branch}'\n{file_adds %
-  >    "HG: added {file}\n"     }{file_mods %
-  >    "HG: changed {file}\n"   }{file_dels %
-  >    "HG: removed {file}\n"   }{if(files, "",
-  >    "HG: no files changed\n")}
+  >     HG: branch '{branch}'\n{listupfiles}
   > EOF
 
   $ echo bbbb > file