[PATCH 4/4] Add a couple of safety checks to series creation

[Yann Dirson <ydirson@altern.org>]

From: Yann Dirson <ydirson@altern.org>

Check first whether the operation can complete, instead of
bombing out halfway.
---

 stgit/commands/branch.py |    5 +++
 stgit/stack.py           |    7 ++++-
 t/t1000-branch-create.sh |   66 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/stgit/commands/branch.py b/stgit/commands/branch.py
index c4b5945..c95e529 100644
--- a/stgit/commands/branch.py
+++ b/stgit/commands/branch.py
@@ -122,12 +122,15 @@ def func(parser, options, args):
         check_conflicts()
         check_head_top_equal()
 
+        if git.branch_exists(args[0]):
+            raise CmdException, 'Branch "%s" already exists' % args[0]
+        
         tree_id = None
         if len(args) == 2:
             tree_id = git_id(args[1])
 
-        git.create_branch(args[0], tree_id)
         stack.Series(args[0]).init()
+        git.create_branch(args[0], tree_id)
 
         print 'Branch "%s" created.' % args[0]
         return
diff --git a/stgit/stack.py b/stgit/stack.py
index 92407e7..236e67f 100644
--- a/stgit/stack.py
+++ b/stgit/stack.py
@@ -431,8 +431,13 @@ class Series:
         """
         bases_dir = os.path.join(self.__base_dir, 'refs', 'bases')
 
-        if self.is_initialised():
+        if os.path.exists(self.__patch_dir):
             raise StackException, self.__patch_dir + ' already exists'
+        if os.path.exists(self.__refs_dir):
+            raise StackException, self.__refs_dir + ' already exists'
+        if os.path.exists(self.__base_file):
+            raise StackException, self.__base_file + ' already exists'
+
         os.makedirs(self.__patch_dir)
 
         if not os.path.isdir(bases_dir):
diff --git a/t/t1000-branch-create.sh b/t/t1000-branch-create.sh
new file mode 100755
index 0000000..bee0b1c
--- /dev/null
+++ b/t/t1000-branch-create.sh
@@ -0,0 +1,66 @@
+#!/bin/sh
+#
+# Copyright (c) 2006 Yann Dirson
+#
+
+test_description='Branch operations.
+
+Exercises the "stg branch" commands.
+'
+
+. ./test-lib.sh
+
+test_stg_init
+
+test_expect_failure \
+    'Try to create an stgit branch with a spurious refs/patches/ entry' \
+    'find .git -name foo | xargs rm -rf &&
+     touch .git/refs/patches/foo &&
+     stg branch -c foo
+'
+
+test_expect_success \
+    'Check no part of the branch was created' \
+    'test "`find .git -name foo | tee /dev/stderr`" = ".git/refs/patches/foo"
+'
+
+
+test_expect_failure \
+    'Try to create an stgit branch with a spurious patches/ entry' \
+    'find .git -name foo | xargs rm -rf &&
+     touch .git/patches/foo &&
+     stg branch -c foo
+'
+
+test_expect_success \
+    'Check no part of the branch was created' \
+    'test "`find .git -name foo | tee /dev/stderr`" = ".git/patches/foo"
+'
+
+
+test_expect_failure \
+    'Try to create an stgit branch with a spurious refs/bases/ entry' \
+    'find .git -name foo | xargs rm -rf &&
+     touch .git/refs/bases/foo &&
+     stg branch -c foo
+'
+
+test_expect_success \
+    'Check no part of the branch was created' \
+    'test "`find .git -name foo | tee /dev/stderr`" = ".git/refs/bases/foo"
+'
+
+
+# test_expect_failure \
+#     'Try to create an stgit branch with a spurious refs/heads/ entry' \
+#     'find .git -name foo | xargs rm -rf &&
+#      touch .git/refs/heads/foo &&
+#      stg branch -c foo
+# '
+
+# test_expect_success \
+#     'Check no part of the branch was created' \
+#     'test "`find .git -name foo | tee /dev/stderr`" = ".git/refs/heads/foo"
+# '
+
+test_done