treemanifest: add simple test for tree repack

Summary:
This adds a simple test that verifies hg repack will pack two tree manifest
packs into one.

It caught a bug where creating a treemanifest for a commit with a null parent
produced incorrect output because it constructed an empty tree and tried to use
it's node as the parent of the delta, when there should not have been any delta
in the first place. This is fixed by this diff as well.

Test Plan: Ran the new test

Reviewers: #mercurial, dsyang, rmcelroy

Reviewed By: rmcelroy

Subscribers: rmcelroy, mjpieters

Differential Revision: https://phabricator.intern.facebook.com/D4261591

Signature: t1:4261591:1480705822:ef21fb8cebd8b89f92f58f11bb1dab59bf97664d

ctreemanifest/py-treemanifest.cpp

@@ -1090,16 +1090,21 @@ void writestore(Manifest *mainManifest, const std::vector<char*> &cmpNodes,
 static PyObject *treemanifest_write(py_treemanifest *self, PyObject *args,
                                     PyObject *kwargs) {
   PyObject* packObj;
-  py_treemanifest* p1tree = NULL;
+  PyObject* p1treeObj = NULL;
   PyObject* useDeltaObj = NULL;
 
   static char const *kwlist[] = {"pack", "p1tree", "useDeltas", NULL};
 
   if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O|OO", (char**)kwlist,
-                                   &packObj, &p1tree, &useDeltaObj)) {
+                                   &packObj, &p1treeObj, &useDeltaObj)) {
     return NULL;
   }
 
+  py_treemanifest *p1tree = NULL;
+  if (p1treeObj && p1treeObj != Py_None) {
+    p1tree = (py_treemanifest*)p1treeObj;
+  }
+
   // ParseTuple doesn't increment the ref, but the PythonObj will decrement on
   // destruct, so let's increment now.
   Py_INCREF(packObj);

tests/test-treemanifest-repack.t

@@ -0,0 +1,69 @@
+  $ . "$TESTDIR/library.sh"
+
+  $ PYTHONPATH=$TESTDIR/..:$PYTHONPATH
+  $ export PYTHONPATH
+
+  $ cat >> $HGRCPATH <<EOF
+  > [extensions]
+  > fastmanifest=
+  > treemanifest=
+  > 
+  > [remotefilelog]
+  > usefastdatapack=True
+  > reponame=master
+  > 
+  > [fastmanifest]
+  > usetree=True
+  > usecache=False
+  > EOF
+
+  $ hg init master
+  $ hg clone -q master client
+
+  $ cd master
+  $ echo a > a && hg commit -Aqm 'add a'
+  $ mkdir dir && echo b > dir/b && hg commit -Aqm 'add dir/b'
+
+  $ cd ../client
+  $ cat >> .hg/hgrc <<EOF
+  > [treemanifest]
+  > autocreatetrees=True
+  > EOF
+
+# Test repacking manifest packs
+  $ hg pull -q -r 0
+  $ hg pull -q -r 1
+  $ ls -l $CACHEDIR/master/packs/manifests | grep datapack
+  *  100 * 65df85879cdd898607ee3f323a0b61edc7de25b8.datapack (glob)
+  *  214 * ed42c8e98d598b7c9de7c2660f2a833bb5198b54.datapack (glob)
+
+  $ hg debugdatapack $CACHEDIR/master/packs/manifests/65df85879cdd898607ee3f323a0b61edc7de25b8
+  
+  
+  Node          Delta Base    Delta Length
+  a0c8bcbbb45c  000000000000  43
+
+  $ hg debugdatapack $CACHEDIR/master/packs/manifests/ed42c8e98d598b7c9de7c2660f2a833bb5198b54
+  
+  dir/
+  Node          Delta Base    Delta Length
+  23226e7a252c  000000000000  43
+  
+  
+  Node          Delta Base    Delta Length
+  1832e0765de9  a0c8bcbbb45c  58
+  $ hg repack
+
+  $ ls -l $CACHEDIR/master/packs/manifests | grep datapack
+  *  313 * c217b22cf43133a289290b6ac32d95f2b5a8361e.datapack (glob)
+
+  $ hg debugdatapack $CACHEDIR/master/packs/manifests/c217b22cf43133a289290b6ac32d95f2b5a8361e
+  
+  
+  Node          Delta Base    Delta Length
+  1832e0765de9  a0c8bcbbb45c  58
+  a0c8bcbbb45c  000000000000  43
+  
+  dir/
+  Node          Delta Base    Delta Length
+  23226e7a252c  000000000000  43

treemanifest/__init__.py

@@ -130,7 +130,9 @@ def recordmanifest(pack, repo, oldtip, newtip):
         p1 = mfrevlog.parentrevs(rev)[0]
         p1node = mfrevlog.node(p1)
 
-        if p1node in builttrees:
+        if p1node == nullid:
+            origtree = ctreemanifest.treemanifest(repo.svfs.manifestdatastore)
+        elif p1node in builttrees:
             origtree = builttrees[p1node]
         else:
             origtree = mfl[p1node].read()._treemanifest()
@@ -207,7 +209,7 @@ def recordmanifest(pack, repo, oldtip, newtip):
             newtree.set(fname, fnode, fflags)
 
         newtree.write(InterceptedMutablePack(pack, mfrevlog.node(rev), p1node),
-                      origtree)
+                      origtree if p1node != nullid else None)
 
         if ui.configbool('treemanifest', 'verifyautocreate', True):
             diff = newtree.diff(origtree)