Merge lp:~jameinel/bzr/preview-pull-760152 into lp:bzr/2.3

[John A Meinel]

Bug #760152, 'bzr merge --preview --pull' should not change the last-revision (be equivalent to "bzr merge --preview")

This is a small tweak to the merge code.

Basically, if you use "bzr merge --preview" it shows you the diff, without changing the WorkingTree. It turns out that "bzr merge --pull --preview" would apply "--pull" and change the branch's last-revision even though it really should just "--preview"

I'm targeting 2.3, though we could easily backport this as far back as we want. (The initial change is on the 2.1 branch, but the NEWS update is obviously on 2.3)

[Jelmer Vernooij (jelmer)]

On Wed, 2011-04-20 at 09:54 +0000, John A Meinel wrote:
> John A Meinel has proposed merging lp:~jameinel/bzr/preview-pull-760152 into lp:bzr/2.3.
>
> Requested reviews:
> bzr-core (bzr-core)
> Related bugs:
> Bug #760152 in Bazaar: "bzr merge --pull --preview BRANCH does not always honor the --preview option"
> https://bugs.launchpad.net/bzr/+bug/760152
>
> For more details, see:
> https://code.launchpad.net/~jameinel/bzr/preview-pull-760152/+merge/58460
>
> This is a small tweak to the merge code.

   review approve

> I'm targeting 2.3, though we could easily backport this as far back as we want. (The initial change is on the 2.1 branch, but the NEWS update is obviously on 2.3)
Since this was only reported recently I wonder many people will actually
be affected by this and so how useful it would be to backport further
than 2.3. On the other hand, it also doesn't look like a very risky
change.

Cheers,

Jelmer

review: Approve

[John A Meinel (jameinel)]

sent to pqm by email

=== modified file 'bzrlib/builtins.py'
--- bzrlib/builtins.py	2011-01-12 01:01:53 +0000
+++ bzrlib/builtins.py	2011-04-20 09:55:15 +0000
@@ -3948,7 +3948,7 @@
             merger.other_rev_id is not None):
             note('Nothing to do.')
             return 0
-        if pull:
+        if pull and not preview:
             if merger.interesting_files is not None:
                 raise errors.BzrCommandError('Cannot pull individual files')
             if (merger.base_rev_id == tree.last_revision()):

=== modified file 'bzrlib/tests/blackbox/test_merge.py'
--- bzrlib/tests/blackbox/test_merge.py	2010-12-02 10:41:05 +0000
+++ bzrlib/tests/blackbox/test_merge.py	2011-04-20 09:55:15 +0000
@@ -19,8 +19,11 @@
 """Black-box tests for bzr merge.
 """
 
+import doctest
 import os
 
+from testtools import matchers
+
 from bzrlib import (
     branch,
     branchbuilder,
@@ -352,13 +355,13 @@
 
     def pullable_branch(self):
         tree_a = self.make_branch_and_tree('a')
-        self.build_tree(['a/file'])
+        self.build_tree_contents([('a/file', 'bar\n')])
         tree_a.add(['file'])
         self.id1 = tree_a.commit('commit 1')
 
         tree_b = self.make_branch_and_tree('b')
         tree_b.pull(tree_a.branch)
-        file('b/file', 'wb').write('foo')
+        self.build_tree_contents([('b/file', 'foo\n')])
         self.id2 = tree_b.commit('commit 2')
 
     def test_merge_pull(self):
@@ -369,6 +372,21 @@
         tree_a = workingtree.WorkingTree.open('.')
         self.assertEqual([self.id2], tree_a.get_parent_ids())
 
+    def test_merge_pull_preview(self):
+        self.pullable_branch()
+        (out, err) = self.run_bzr('merge --pull --preview -d a b')
+        self.assertThat(out, matchers.DocTestMatches(
+"""=== modified file 'file'
+--- file\t...
++++ file\t...
+@@ -1,1 +1,1 @@
+-bar
++foo
+
+""", doctest.ELLIPSIS | doctest.REPORT_UDIFF))
+        tree_a = workingtree.WorkingTree.open('a')
+        self.assertEqual([self.id1], tree_a.get_parent_ids())
+
     def test_merge_kind_change(self):
         tree_a = self.make_branch_and_tree('tree_a')
         self.build_tree_contents([('tree_a/file', 'content_1')])

=== modified file 'doc/en/release-notes/bzr-2.3.txt'
--- doc/en/release-notes/bzr-2.3.txt	2011-04-08 08:03:30 +0000
+++ doc/en/release-notes/bzr-2.3.txt	2011-04-20 09:55:15 +0000
@@ -49,6 +49,10 @@
    plugins because it's often too long.
    (Martin Pool, #716389)
 
+* ``bzr merge --preview --pull`` should respect the ``--preview`` option
+  first, and not actually change the branch tip revision.
+  (John Arbash Meinel, Dennis Duchier, #760152)
+
 * ``bzr push`` into a repository (that doesn't have a branch), will no
   longer copy all revisions in the repository. Only the ones in the
   ancestry of the source branch, like it does in all other cases.