[StGit PATCH] Print conflict details with the new infrastructure (bug #11181)

[Catalin Marinas <catalin.marinas@gmail.com>]

The patch modifies the IndexAndWorkTree.merge() function to display
pass the conflict information (files) when raising an exception. The
logic is similar to the one in the old infrastructure.

Signed-off-by: Catalin Marinas <catalin.marinas@gmail.com>
---
 stgit/lib/git.py         |   14 +++++++++-----
 stgit/lib/transaction.py |    8 +++++---
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/stgit/lib/git.py b/stgit/lib/git.py
index 0a208ef..6457893 100644
--- a/stgit/lib/git.py
+++ b/stgit/lib/git.py
@@ -829,12 +829,16 @@ class IndexAndWorktree(RunWithEnvCwd):
                          env = { 'GITHEAD_%s' % base.sha1: 'ancestor',
                                  'GITHEAD_%s' % ours.sha1: 'current',
                                  'GITHEAD_%s' % theirs.sha1: 'patched'})
-            r.discard_output()
+            r.returns([0, 1])
+            output = r.output_lines()
+            if r.exitcode:
+                # There were conflicts
+                conflicts = [l for l in output if l.startswith('CONFLICT')]
+                err = '%d conflict(s)\n%s' \
+                        % (len(conflicts), ''.join(conflicts))
+                raise MergeConflictException(err)
         except run.RunException, e:
-            if r.exitcode == 1:
-                raise MergeConflictException()
-            else:
-                raise MergeException('Index/worktree dirty')
+            raise MergeException('Index/worktree dirty')
     def changed_files(self, tree, pathlimits = []):
         """Return the set of files in the worktree that have changed with
         respect to C{tree}. The listing is optionally restricted to
diff --git a/stgit/lib/transaction.py b/stgit/lib/transaction.py
index 0f414d8..b8e82b6 100644
--- a/stgit/lib/transaction.py
+++ b/stgit/lib/transaction.py
@@ -201,7 +201,8 @@ class StackTransaction(object):
             self.__stack.set_head(new_head, self.__msg)
 
         if self.__error:
-            out.error(self.__error)
+            error_lines = self.__error.split('\n')
+            out.error(*error_lines)
 
         # Write patches.
         def write(msg):
@@ -311,9 +312,10 @@ class StackTransaction(object):
                 tree = iw.index.write_tree()
                 self.__current_tree = tree
                 s = ' (modified)'
-            except git.MergeConflictException:
+            except git.MergeConflictException, e:
                 tree = ours
                 merge_conflict = True
+                conflict_error = str(e)
                 s = ' (conflict)'
             except git.MergeException, e:
                 self.__halt(str(e))
@@ -344,7 +346,7 @@ class StackTransaction(object):
 
             # Save this update so that we can run it a little later.
             self.__conflicting_push = update
-            self.__halt('Merge conflict')
+            self.__halt(conflict_error)
         else:
             # Update immediately.
             update()