Subject: [StGit PATCH 2/2] Check for top == head at the start of every transaction

From: Karl Hasselström <[email-masked]>
Date: Thu, 28 Aug 2008 00:06:57 +0200

We used to check it in the run() method, but that's sometimes too
late: for example, it causes stg coalesce to ask for a commit message
_before_ the check, resulting in a lost commit message if the check
fails.

As before, the check can be disabled for the few commands that need
it.

Signed-off-by: Karl Hasselström <[email-masked]>

---

 stgit/commands/redo.py     |    3 ++-
 stgit/commands/reset.py    |    3 ++-
 stgit/commands/uncommit.py |    3 ++-
 stgit/commands/undo.py     |    3 ++-
 stgit/lib/transaction.py   |   11 ++++++++---
 t/t2600-coalesce.sh        |    2 +-
 6 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/stgit/commands/redo.py b/stgit/commands/redo.py
index a1075ec..97b7edc 100644
--- a/stgit/commands/redo.py
+++ b/stgit/commands/redo.py
@@ -44,7 +44,8 @@ def func(parser, options, args):
         raise common.CmdException('Bad number of undos to redo')
     state = log.undo_state(stack, -options.number)
     trans = transaction.StackTransaction(stack, 'redo %d' % options.number,
-                                         discard_changes = options.hard)
+                                         discard_changes = options.hard,
+                                         allow_bad_head = True)
     try:
         log.reset_stack(trans, stack.repository.default_iw, state)
     except transaction.TransactionHalted:
diff --git a/stgit/commands/reset.py b/stgit/commands/reset.py
index 2499b26..d79ce70 100644
--- a/stgit/commands/reset.py
+++ b/stgit/commands/reset.py
@@ -56,7 +56,8 @@ def func(parser, options, args):
     else:
         raise common.CmdException('Wrong number of arguments')
     trans = transaction.StackTransaction(stack, 'reset',
-                                         discard_changes = options.hard)
+                                         discard_changes = options.hard,
+                                         allow_bad_head = True)
     try:
         if patches:
             log.reset_stack_partially(trans, stack.repository.default_iw,
diff --git a/stgit/commands/uncommit.py b/stgit/commands/uncommit.py
index c21306b..3ffdc1e 100644
--- a/stgit/commands/uncommit.py
+++ b/stgit/commands/uncommit.py
@@ -132,7 +132,8 @@ def func(parser, options, args):
         patchnames.reverse()
 
     trans = transaction.StackTransaction(stack, 'uncommit',
-                                         allow_conflicts = True)
+                                         allow_conflicts = True,
+                                         allow_bad_head = True)
     for commit, pn in zip(commits, patchnames):
         trans.patches[pn] = commit
     trans.applied = list(reversed(patchnames)) + trans.applied
diff --git a/stgit/commands/undo.py b/stgit/commands/undo.py
index 58f1da6..a9cee3a 100644
--- a/stgit/commands/undo.py
+++ b/stgit/commands/undo.py
@@ -41,7 +41,8 @@ def func(parser, options, args):
         raise common.CmdException('Bad number of commands to undo')
     state = log.undo_state(stack, options.number)
     trans = transaction.StackTransaction(stack, 'undo %d' % options.number,
-                                         discard_changes = options.hard)
+                                         discard_changes = options.hard,
+                                         allow_bad_head = True)
     try:
         log.reset_stack(trans, stack.repository.default_iw, state)
     except transaction.TransactionHalted:
diff --git a/stgit/lib/transaction.py b/stgit/lib/transaction.py
index 7c7139c..c6e2db3 100644
--- a/stgit/lib/transaction.py
+++ b/stgit/lib/transaction.py
@@ -75,7 +75,7 @@ class StackTransaction(object):
       your refs and index+worktree, or fail without having done
       anything."""
     def __init__(self, stack, msg, discard_changes = False,
-                 allow_conflicts = False):
+                 allow_conflicts = False, allow_bad_head = False):
         """Create a new L{StackTransaction}.
 
         @param discard_changes: Discard any changes in index+worktree
@@ -99,6 +99,8 @@ class StackTransaction(object):
         else:
             self.__allow_conflicts = allow_conflicts
         self.__temp_index = self.temp_index_tree = None
+        if not allow_bad_head:
+            self.__assert_head_top_equal()
     stack = property(lambda self: self.__stack)
     patches = property(lambda self: self.__patches)
     def __set_applied(self, val):
@@ -137,13 +139,16 @@ class StackTransaction(object):
     def __set_head(self, val):
         self.__bad_head = val
     head = property(__get_head, __set_head)
-    def __checkout(self, tree, iw, allow_bad_head):
-        if not (allow_bad_head or self.__stack.head_top_equal()):
+    def __assert_head_top_equal(self):
+        if not self.__stack.head_top_equal():
             out.error(
                 'HEAD and top are not the same.',
                 'This can happen if you modify a branch with git.',
                 '"stg repair --help" explains more about what to do next.')
             self.__abort()
+    def __checkout(self, tree, iw, allow_bad_head):
+        if not allow_bad_head:
+            self.__assert_head_top_equal()
         if self.__current_tree == tree and not self.__discard_changes:
             # No tree change, but we still want to make sure that
             # there are no unresolved conflicts. Conflicts
diff --git a/t/t2600-coalesce.sh b/t/t2600-coalesce.sh
index 33c073d..9a043fd 100755
--- a/t/t2600-coalesce.sh
+++ b/t/t2600-coalesce.sh
@@ -33,7 +33,7 @@ cat > editor <<EOF
 echo "Editor was invoked" | tee editor-invoked
 EOF
 chmod a+x editor
-test_expect_failure 'Coalesce with top != head' '
+test_expect_success 'Coalesce with top != head' '
     echo blahonga >> foo.txt &&
     git commit -a -m "a new commit" &&
     EDITOR=./editor command_error stg coalesce --name=r0 p0 q1 &&