commands: don't do too much work for error messages

mercurial/commands.py

@@ -1422,26 +1422,27 b' def heads(ui, repo, *branchrevs, **opts)'
         heads = repo.heads(start)
 
     else:
+
         if hideinactive:
             dagheads = repo.heads(start)
         decode, encode = encoding.fromlocal, encoding.tolocal
         branches = set(repo[decode(br)].branch() for br in branchrevs)
         heads = []
-        visitedset = set()
+
         for b in branches:
             bheads = repo.branchheads(b, start, closed=closed)
-            if not bheads:
-                encodedbranch = encode(b)
-                if not opts.get('rev'):
-                    ui.warn(_("no open branch heads on branch %s\n")
-                            % encodedbranch)
-                else:
-                    ui.warn(_("no changes on branch %s are reachable from %s\n")
-                            % (encodedbranch, opts.get('rev')))
             if hideinactive:
                 bheads = [bhead for bhead in bheads if bhead in dagheads]
             heads.extend(bheads)
 
+        haveheads = set(repo[h].branch() for h in heads)
+        if branches - haveheads:
+            headless = ', '.join(encode(b) for b in branches - haveheads)
+            msg = _('no open branch heads found on branches %s')
+            if opts.get('rev'):
+                msg += _(' (started at %s)' % opts['rev'])
+            ui.warn((msg + '\n') % headless)
+
     if not heads:
         return 1
 

tests/test-bheads.out

@@ -56,7 +56,7 b' 1: Adding a branch'
 -------
 7: Adding c branch
 =======
-no changes on branch c are reachable from 3
+no open branch heads found on branches c (started at 3)
 1
 -------
 7: Adding c branch
@@ -72,7 +72,7 b' 6: Merging b branch head 2 and b branch '
 3: Adding b branch head 1
 0
 -------
-no changes on branch b are reachable from 7
+no open branch heads found on branches b (started at 7)
 1
 =======
 0 files updated, 0 files merged, 2 files removed, 0 files unresolved

tests/test-branches.out

@@ -117,7 +117,7 b' c 6:589736a'
 a                              5:d8cbc61dbaa6 (inactive)
 default                        0:19709c5a4e75 (inactive)
 a branch name much longer than the default justification used by branches 7:10ff5895aa57
-no open branch heads on branch b
+no open branch heads found on branches b
 changeset:   12:2da6583810df
 branch:      b
 tag:         tip
@@ -169,6 +169,7 b' user: test'
 date:        Thu Jan 01 00:00:04 1970 +0000
 summary:     Adding b branch head 2
 
+no open branch heads found on branches a
 % branch b
 changeset:   13:6ac12926b8c3
 branch:      b