[PATCH 2 of 2] templates: make divergentnodes in whyunstable keyword be a mappinglist too (RFC)

[Anton Shestakov]

# HG changeset patch
# User Anton Shestakov <av6 at dwimlabs.net>
# Date 1523705764 -28800
#      Sat Apr 14 19:36:04 2018 +0800
# Node ID 6287c68bde7bcdc1dc260da9983ecc7fffc9ee20
# Parent  987c05eac1801d0b919c874280d03f9e8cccb411
templates: make divergentnodes in whyunstable keyword be a mappinglist too (RFC)

I'd like this to work, but it doesn't: "{divergentnodes}" show a178212c3433 as
the divergent node, and not 70d5a63ca112 (so the whole test case fails).

diff --git a/mercurial/templatekw.py b/mercurial/templatekw.py
--- a/mercurial/templatekw.py
+++ b/mercurial/templatekw.py
@@ -800,20 +800,17 @@ def showwhyunstable(context, mapping):
     """
     repo = context.resource(mapping, 'repo')
     ctx = context.resource(mapping, 'ctx')
-
-    def formatnode(ctx):
-        return ' %s (%s)' % (scmutil.formatchangeid(ctx), ctx.phasestr())
-
     entries = obsutil.whyunstable(repo, ctx)
+    mappinglist = templateutil.mappinglist
 
     for entry in entries:
         if entry.get('divergentnodes'):
-            dnodes = entry['divergentnodes']
-            entry['divergentnodes'] = ''.join(formatnode(dnode)
-                                              for dnode in dnodes)
+            dnodes = [{ctx: dnode} for dnode in entry['divergentnodes']]
+            tmpl = ' {rev}:{node|short} ({phase})'
+            entry['divergentnodes'] = mappinglist(dnodes, tmpl=tmpl)
 
     tmpl = '{instability}:{divergentnodes} {reason} {node|short}'
-    return templateutil.mappinglist(entries, tmpl=tmpl, sep='\n')
+    return mappinglist(entries, tmpl=tmpl, sep='\n')
 
 def loadkeyword(ui, extname, registrarobj):
     """Load template keyword from specified registrarobj
diff --git a/tests/test-obsolete-divergent.t b/tests/test-obsolete-divergent.t
--- a/tests/test-obsolete-divergent.t
+++ b/tests/test-obsolete-divergent.t
@@ -725,6 +725,8 @@ Use scmutil.cleanupnodes API to create d
   content-divergent: 4:70d5a63ca112 (draft) predecessor a178212c3433
   $ hg log -r 1a2a9b5b0030 --hidden -T '{whyunstable%"{instability}:{divergentnodes} {reason} {node}\n"}'
   content-divergent: 4:70d5a63ca112 (draft) predecessor a178212c3433c4e77b573f6011e29affb8aefa33
+  $ hg log -r 1a2a9b5b0030 --hidden -T '{whyunstable%"{instability}:{divergentnodes % " {node} ({phase})"} {reason} {node}\n"}'
+  content-divergent: 70d5a63ca112acb3764bc1d7320ca90ea688d671 (draft) predecessor a178212c3433c4e77b573f6011e29affb8aefa33
 
 #if serve