commit: fix display of 'created new head' message (issue2186)

To avoid recurrent fixes for the display of this message, a summary table with
all case combinations has been added to the code.
Basically, there is two condition for the message to be printed:
* this is not an initial (named branch or topo) root
* none of the parents are in the current branch heads

mercurial/commands.py

@@ -766,9 +766,37 b' def commit(ui, repo, *pats, **opts):'
     ctx = repo[node]
     parents = ctx.parents()
 
-    if bheads and [x for x in parents
-                   if x.node() not in bheads and x.branch() == branch]:
+    if bheads and not [x for x in parents
+                       if x.node() in bheads and x.branch() == branch]:
         ui.status(_('created new head\n'))
+        # The message is not printed for initial roots. For the other
+        # changesets, it is printed in the following situations:
+        #
+        # Par column: for the 2 parents with ...
+        #   N: null or no parent
+        #   B: parent is on another named branch
+        #   C: parent is a regular non head changeset
+        #   H: parent was a branch head of the current branch
+        # Msg column: whether we print "created new head" message
+        # In the following, it is assumed that there already exists some
+        # initial branch heads of the current branch, otherwise nothing is
+        # printed anyway.
+        #
+        # Par Msg Comment
+        # NN   y  additional topo root
+        #
+        # BN   y  additional branch root
+        # CN   y  additional topo head
+        # HN   n  usual case
+        #
+        # BB   y  weird additional branch root
+        # CB   y  branch merge
+        # HB   n  merge with named branch
+        #
+        # CC   y  additional head from merge
+        # CH   n  merge with a head
+        #
+        # HH   n  head merge: head count decreases
 
     if not opts.get('close_branch'):
         for r in parents:

tests/test-backout.out

@@ -73,6 +73,7 b' adding file1'
 marked working directory as branch branch2
 adding file2
 removing file1
+created new head
 changeset 3:d4e8f6db59fb backs out changeset 1:bf1602f437f3
 the backout changeset is a new head - do not forget to merge
 (use "backout --merge" if you want to auto-merge)

tests/test-branch-option.out

@@ -17,6 +17,7 b' 1 files updated, 0 files merged, 0 files'
 marked working directory as branch æ
 1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 marked working directory as branch b
+created new head
 in rev c branch a
 1:dd6e60a716c6
 2:f25d57ab0566

tests/test-fetch.out

@@ -182,6 +182,7 b' marked working directory as branch secon'
 adding b
 marked working directory as branch default
 adding c
+created new head
 updating to branch default
 3 files updated, 0 files merged, 0 files removed, 0 files unresolved
 % fetch should succeed

tests/test-newbranch.out

@@ -4,6 +4,7 b' marked working directory as branch bar'
 % branch shadowing
 abort: a branch of the same name already exists (use 'hg update' to switch to it)
 marked working directory as branch default
+created new head
 % there should be only one default branch head
 changeset:   3:bf1bc2f45e83
 tag:         tip

tests/test-push-warn.out

@@ -279,8 +279,10 b' updating to branch B'
 1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 1 files updated, 0 files merged, 1 files removed, 0 files unresolved
 marked working directory as branch B
+created new head
 1 files updated, 0 files merged, 1 files removed, 0 files unresolved
 marked working directory as branch A
+created new head
 %% glog of local
 @  5: A b3
 |

tests/test-subrepo.out

@@ -90,7 +90,6 b' path t'
  source   t
  revision 6747d179aa9a688023c4b0cad32e4c92bb7f34ad
 committing subrepository t
-created new head
   searching for copies back to rev 2
 resolving manifests
  overwrite None partial False