hgweb: display fate of obsolete changesets Operations that obsolete changesets store enough metadata to explain what happened after the fact. One way to get that metadata is showsuccsandmarkers function, which returns a list of successors of a particular changeset and appropriate obsolescence markers. Templates have a set of experimental functions that have names starting with obsfate. This patch uses some of these functions to interpret output of succsandmarkers() and produce human-friendly messages that describe what happened to an obsolete changeset, e.g. "pruned" or "rewritten as 6:3de5eca88c00". In commonentry(), succsandmarkers property is made callable so it's only executed on demand; this saves time when changeset is not obsolete, and also in e.g. /shortlog view, where there are a lot of changesets, but we don't need to show each and every one in detail. In spartan theme, succsandmarkers is used instead of the simple "obsolete: yes", in other themes a new line is added to /rev page.

--- a/mercurial/hgweb/webutil.py	Sat Dec 16 18:58:02 2017 -0500
+++ b/mercurial/hgweb/webutil.py	Tue Nov 21 17:03:41 2017 +0800
@@ -32,6 +32,7 @@
     pathutil,
     pycompat,
     templatefilters,
+    templatekw,
     ui as uimod,
     util,
 )
@@ -351,6 +352,9 @@
 def formatlinerange(fromline, toline):
     return '%d:%d' % (fromline + 1, toline)
 
+def succsandmarkers(repo, ctx):
+    return templatekw.showsuccsandmarkers(repo, ctx)
+
 def commonentry(repo, ctx):
     node = ctx.node()
     return {
@@ -362,6 +366,7 @@
         'extra': ctx.extra(),
         'phase': ctx.phasestr(),
         'obsolete': ctx.obsolete(),
+        'succsandmarkers': lambda **x: succsandmarkers(repo, ctx),
         'instabilities': [{"instability": i} for i in ctx.instabilities()],
         'branch': nodebranchnodefault(ctx),
         'inbranch': nodeinbranch(repo, ctx),