treemanifest: test for pulling normal scratch branch into treeonly repo

Adds a test and improves output for dealing pulling a normal scratch branch into
a treeonly repo (so the manifest doesn't exist).

In the future we could fix this by having the server generate the trees on the
fly for infinitepush branches that don't already have them.

Differential Revision: https://phab.mercurial-scm.org/D1268

tests/test-treemanifest-infinitepush.t

@@ -193,6 +193,19 @@ Pull a treeonly scratch branch into a treeonly client
   -rw-r--r--       0 undo.phaseroots
 
 Pull a normal scratch branch into a treeonly client
+  $ hg pull -r scratch/nontree
+  pulling from ssh://user@dummy/master
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files (+1 heads)
+  new changesets 42ec76eb772a
+  (run 'hg heads' to see heads, 'hg merge' to merge)
+  $ hg log -r 42ec76eb772a -T ' ' --stat
+  abort: unable to download the following trees from the server:
+  bf0601d5cb94247e00d0bdd1d8327f0dd36f54e9
+  [255]
   $ cd ..
 
 Verify its not on the server

treemanifest/__init__.py

@@ -679,9 +679,8 @@ def _unpackmanifestscg1(orig, self, repo, *args, **kwargs):
 
     if repo.ui.configbool('treemanifest', 'treeonly'):
         self.manifestheader()
-        chain = None
-        for chunkdata in iter(lambda: self.deltachunk(chain), {}):
-            chain = chunkdata['node']
+        for chunkdata in self.deltaiter():
+            pass
         return
 
     mfrevlog = repo.manifestlog._revlog
@@ -1008,8 +1007,13 @@ def _prefetchtrees(repo, rootdir, mfnodes, basemfnodes, directories):
             raise error.Abort(_("unable to download %d trees (%s,...)") %
                                (len(missingnodes), list(missingnodes)[0]))
     except bundle2.AbortFromPart as exc:
-        repo.ui.status(_('remote: abort: %s\n') % exc)
-        raise error.Abort(_('pull failed on remote'), hint=exc.hint)
+        repo.ui.debug('remote: abort: %s\n' % exc)
+        hexnodes = list(hex(mfnode) for mfnode in mfnodes)
+        nodestr = '\n'.join(hexnodes[:10])
+        if len(hexnodes) > 10:
+            nodestr += '\n...'
+        raise error.Abort(_('unable to download the following trees from the '
+                            'server:\n%s') % nodestr, hint=exc.hint)
     except error.BundleValueError as exc:
         raise error.Abort(_('missing support for %s') % exc)
     finally: