[PATCH] bookmarks: restrict moving a bookmark to it's descendants (issue1502)

[David Soria Parra]

# HG changeset patch
# User David Soria Parra <dsp at php.net>
# Date 1298554730 -3600
# Node ID f408378b758770e02ec2ab0aa7fee047278cc750
# Parent  b2e4e394d742ca3a948848dc2aa9d288c0eaa861
bookmarks: restrict moving a bookmark to it's descendants (issue1502)

A bookmark can only move to a descendant on commit, pull or
unbundle. Bookmarks cannot jump between heads anymore. This fixese
issue 1502.

We explicitly use new.node(), to emphasise that we are updating the
current bookmark to the new node.

diff --git a/mercurial/bookmarks.py b/mercurial/bookmarks.py
--- a/mercurial/bookmarks.py
+++ b/mercurial/bookmarks.py
@@ -127,8 +127,11 @@
     update = False
     mark = repo._bookmarkcurrent
     if mark and marks[mark] in parents:
-        marks[mark] = node
-        update = True
+        old = repo[marks[mark]]
+        new = repo[node]
+        if new in old.descendants():
+            marks[mark] = new.node()
+            update = True
     if update:
         write(repo)
 
diff --git a/tests/test-issue1502.t b/tests/test-issue1502.t
new file mode 100755
--- /dev/null
+++ b/tests/test-issue1502.t
@@ -0,0 +1,42 @@
+http://mercurial.selenic.com/bts/issue1502
+
+Initialize repository
+
+  $ hg init foo
+  $ touch foo/a && hg -R foo commit -A -m "added a"
+  adding a
+
+  $ hg clone foo foo1
+  updating to branch default
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+  $ echo "bar" > foo1/a && hg -R foo1 commit -m "edit a in foo1"
+  $ echo "hi" > foo/a && hg -R foo commit -m "edited a foo"
+  $ hg -R foo1 pull -u
+  pulling from $TESTTMP/foo
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files (+1 heads)
+  not updating, since new heads added
+  (run 'hg heads' to see heads, 'hg merge' to merge)
+
+  $ hg -R foo1 book branchy
+  $ hg -R foo1 book
+   * branchy                   1:e3e522925eff
+
+Pull. Bookmark should not jump to new head.
+
+  $ echo "there" >> foo/a && hg -R foo commit -m "edited a again"
+  $ hg -R foo1 pull
+  pulling from $TESTTMP/foo
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  (run 'hg update' to get a working copy)
+
+  $ hg -R foo1 book
+   * branchy                   1:e3e522925eff