[PATCH] debugobsolete: add an option to show marker index

[Kostia Balytskyi]

# HG changeset patch
# User Kostia Balytskyi <ikostia at fb.com>
# Date 1458715471 25200
#      Tue Mar 22 23:44:31 2016 -0700
# Node ID d15ea5b6dec8d82ae8e1d48d640b3be39c1ca81b
# Parent  c11f0992d1246286a6a0b2531ff5f31948abcf58
debugobsolete: add an option to show marker index

A bigger picture is the ability to be delete an arbitrary marker form the
repo's obsstore. This is a useful debug ability and it needs a way to indentify
the marker one wants to delete. Having a marker's index provides such an
ability.

diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -1597,10 +1597,12 @@ def show_changeset(ui, repo, opts, buffe
         raise error.Abort(inst.args[0])
     return t
 
-def showmarker(ui, marker):
+def showmarker(ui, marker, index=None):
     """utility function to display obsolescence marker in a readable way
 
     To be used by debug function."""
+    if index is not None:
+        ui.write("%i " % index)
     ui.write(hex(marker.precnode()))
     for repl in marker.succnodes():
         ui.write(' ')
diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -3029,6 +3029,7 @@ def debuglocks(ui, repo, **opts):
          ('', 'record-parents', False,
           _('record parent information for the precursor')),
          ('r', 'rev', [], _('display markers relevant to REV')),
+         ('', 'index', False, _('display index of the marker')),
         ] + commitopts2,
          _('[OBSOLETED [REPLACEMENT ...]]'))
 def debugobsolete(ui, repo, precursor=None, *successors, **opts):
@@ -3091,8 +3092,9 @@ def debugobsolete(ui, repo, precursor=No
         else:
             markers = obsolete.getmarkers(repo)
 
-        for m in markers:
-            cmdutil.showmarker(ui, m)
+        for i, m in enumerate(markers):
+            ind = i if opts.get('index') else None
+            cmdutil.showmarker(ui, m, index=ind)
 
 @command('debugpathcomplete',
          [('f', 'full', None, _('complete an entire path')),
diff --git a/tests/test-debugcommands.t b/tests/test-debugcommands.t
--- a/tests/test-debugcommands.t
+++ b/tests/test-debugcommands.t
@@ -126,3 +126,18 @@ Test internal debugstacktrace command
    debugstacktrace.py:7 *in * (glob)
    debugstacktrace.py:6 *in g (glob)
    */util.py:* in debugstacktrace (glob)
+
+Test that debugobsolete command supports --intex option
+  $ cd ..
+  $ echo "[experimental]" >> $HGRCPATH
+  $ echo "evolution=createmarkers" >> $HGRCPATH
+  $ hg init obsrepo
+  $ cd obsrepo
+  $ echo a > a && hg ci -Am a
+  adding a
+  $ hg ci --amend -m b
+  $ hg debugobsolete
+  cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b 0e141029c361d35262b35cc605f6f1e5e999c7f8 0 (Wed Mar 23 06:44:19 2016 +0000) {'user': 'test'}
+  $ hg debugobsolete --index
+  0 cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b 0e141029c361d35262b35cc605f6f1e5e999c7f8 0 (Wed Mar 23 06:44:19 2016 +0000) {'user': 'test'}
+