Merge instead of rebasing upstream changes in `gclient sync` when --merge is given.

tests/gclient_scm_test.py

Index: tests/gclient_scm_test.py
diff --git a/tests/gclient_scm_test.py b/tests/gclient_scm_test.py
index 5607f85dda123b20633d3daaf9003d91e43fda66..c6038779556f877293099a21ea0c21a929160728 100755
--- a/tests/gclient_scm_test.py
+++ b/tests/gclient_scm_test.py
@@ -752,6 +752,20 @@ from :3
 M 100644 :4 a
 M 100644 :5 b
 
+blob
+mark :7
+data 5
+Mooh
+
+commit refs/heads/feature
+mark :8
+author Bob <bob@example.com> 1390311986 -0000
+committer Bob <bob@example.com> 1390311986 -0000
+data 6
+Add C
+from :3
+M 100644 :7 c
+
 reset refs/heads/master
 from :3
 """
@@ -967,6 +981,50 @@ class ManagedGitWrapperTestCase(BaseGitWrapperTestCase):
                       'a7142dc9f0009350b96a11f372b6ea658592aa95')
     sys.stdout.close()
 
+  def testUpdateMerge(self):
+    if not self.enabled:
+      return
+    options = self.Options()
+    options.merge = True
+    scm = gclient_scm.CreateSCM(url=self.url, root_dir=self.root_dir,
+                                relpath=self.relpath)
+    scm._Run(['checkout', '-q', 'feature'], options)
+    rev = scm.revinfo(options, (), None)
+    file_list = []
+    scm.update(options, (), file_list)
+    self.assertEquals(file_list, [join(self.base_path, x)
+                                  for x in ['a', 'b', 'c']])
+    # The actual commit that is created is unstable, so we verify its tree and
+    # parents instead.
+    self.assertEquals(scm._Capture(['show', '--format=%T', '-s']),
+                      'd2e35c10ac24d6c621e14a1fcadceb533155627d')

[iannucci, 2014/01/21 21:40:47]

Isn't this the same as `git rev-parse HEAD:`?

[Bernhard Bauer, 2014/01/21 23:03:54]

No, this is the tree (i.e. without the commit metadata).

[iannucci, 2014/01/21 23:23:29]

Right, hence the trailing colon :)

HEAD:path refers to tree object in a given commit, and : without the path is the
root tree object.

[Bernhard Bauer, 2014/01/22 15:59:50]

Ooh, that's neat! Done.

+    self.assertEquals(scm._Capture(['rev-parse', 'HEAD^1']), rev)
+    self.assertEquals(scm._Capture(['rev-parse', 'HEAD^2']),
+                      scm._Capture(['rev-parse', 'origin/master']))
+    sys.stdout.close()
+
+  def testUpdateRebase(self):
+    if not self.enabled:
+      return
+    options = self.Options()
+    scm = gclient_scm.CreateSCM(url=self.url, root_dir=self.root_dir,
+                                relpath=self.relpath)
+    scm._Run(['checkout', '-q', 'feature'], options)
+    rev = scm.revinfo(options, (), None)
+    file_list = []
+    # Fake a 'y' key press.
+    __builtin__.raw_input = lambda x: 'y'

[iannucci, 2014/01/21 21:40:47]

scary :). Does this automatically get set back to what it was? Can we use mox to
do this?

[Bernhard Bauer, 2014/01/21 23:03:54]

I have to admit, I stole this from updateConflict below... :) I'll try to make
it a bit less scary tomorrow.

[iannucci, 2014/01/21 23:23:29]

Heh, fair enough... as long as they're both the same hack... This is just not
threadsafe as-is (not that unittests parallelizes tests by default).

[Bernhard Bauer, 2014/01/22 15:59:50]

OK, I made it a method on |scm| which I can override.

+    scm.update(options, (), file_list)
+    self.assertEquals(file_list, [join(self.base_path, x)
+                                  for x in ['a', 'b', 'c']])
+    # The actual commit that is created is unstable, so we verify its tree and
+    # parent instead.
+    self.assertEquals(scm._Capture(['show', '--format=%T', '-s']),
+                      'd2e35c10ac24d6c621e14a1fcadceb533155627d')
+    self.assertEquals(scm._Capture(['rev-parse', 'HEAD^']),
+                      scm._Capture(['rev-parse', 'origin/master']))
+    sys.stdout.close()
+
   def testUpdateReset(self):
     if not self.enabled:
       return