Rewrite 'merge' command

'merge' now traverses every system in the branch root (baserock:morphs)
and merges any chunk or stratum that was changed with 'morph edit'. It
also takes care of updating the refs in the target branch.

5 files changed, 103 insertions, 33 deletions

diff --git a/morphlib/git.py b/morphlib/git.py
index 70915770..0a4b01f4 100644
--- a/morphlib/git.py
+++ b/morphlib/git.py
@@ -150,7 +150,6 @@ def checkout_ref(runcmd, gitdir, ref):
     '''Checks out a specific ref/SHA1 in a git working tree.'''
     runcmd(['git', 'checkout', ref], cwd=gitdir)
 
-
 def reset_workdir(runcmd, gitdir):
     '''Removes any differences between the current commit '''
     '''and the status of the working directory'''
diff --git a/morphlib/plugins/branch_and_merge_plugin.py b/morphlib/plugins/branch_and_merge_plugin.py
index d44ccacc..c2401631 100644
--- a/morphlib/plugins/branch_and_merge_plugin.py
+++ b/morphlib/plugins/branch_and_merge_plugin.py
@@ -49,7 +49,7 @@ class BranchAndMergePlugin(cliapp.Plugin):
         self.app.add_subcommand('show-branch-root', self.show_branch_root,
                                 arg_synopsis='')
         self.app.add_subcommand('merge', self.merge,
-                                arg_synopsis='BRANCH REPO...')
+                                arg_synopsis='BRANCH')
         self.app.add_subcommand('edit', self.edit,
                                 arg_synopsis='SYSTEM STRATUM [CHUNK]')
         self.app.add_subcommand('build', self.build,
@@ -536,24 +536,92 @@ class BranchAndMergePlugin(cliapp.Plugin):
         self.print_changelog('The following changes were made but have not '
                              'been comitted')
 
+    def merge_repo(self, name, from_dir, from_branch, to_dir, to_branch,
+                   is_morphs_repo = False):
+        '''Merge changes for a system branch in a specific repository'''
+
+        if self.get_uncommitted_changes(from_dir) != []:
+            raise cliapp.AppException('repository %s has uncommitted '
+                                      'changes', name)
+        # repo must be made into a URL to avoid ':' in pathnames confusing git
+        from_url = urlparse.urljoin('file://', from_dir)
+        if is_morphs_repo:
+            # We use --no-commit in this case, so we can then revert the refs
+            # that were changed for the system branch in the merge commit
+            self.app.runcmd(['git', 'pull', '--no-commit', '--no-ff', from_url,
+                            from_branch], cwd=to_dir)
+        else:
+            self.app.runcmd(['git', 'pull', '--no-ff', from_url, from_branch],
+                            cwd=to_dir)
+
     def merge(self, args):
-        '''Merge specified repositories from another system branch.'''
+        '''Pull and merge changes from a system branch into the current one.'''
 
-        if len(args) < 2:
-            raise cliapp.AppException('morph merge must get a branch name '
-                                      'and some repo names as arguments')
+        if len(args) != 1:
+            raise cliapp.AppException('morph merge requires a system branch '
+                                      'name as its argument')
 
         workspace = self.deduce_workspace()
-        other_branch, other_branch_dir = \
-                args[0], self.find_system_branch(workspace, args[0])
-        this_branch, this_branch_dir = self.deduce_system_branch()
-
-        for repo in args[1:]:
-            pull_dir = self.find_repository(other_branch_dir, repo)
-            pull_url = urlparse.urljoin('file://', pull_dir)
-            repo_dir = self.find_repository(this_branch_dir, repo)
-            self.app.runcmd(['git', 'pull', pull_url, other_branch],
-                            cwd=repo_dir)
+        from_branch = args[0]
+        from_branch_dir = self.find_system_branch(workspace, from_branch)
+        to_branch, to_branch_dir = self.deduce_system_branch()
+
+        root_repo = self.get_branch_config(from_branch_dir, 'branch.root')
+        other_root_repo = self.get_branch_config(to_branch_dir, 'branch.root')
+        if root_repo != other_root_repo:
+            raise cliapp.AppException('branches do not share a root '
+                                      'repository : %s vs %s' %
+                                      (root_repo, other_root_repo))
+
+        def _merge_chunk(ci):
+            from_repo = self.find_repository(from_branch_dir, ci['repo'])
+            to_repo = self.make_repository_available(
+                to_branch, to_branch_dir, ci['repo'], to_branch)
+            self.merge_repo(
+                ci['repo'], from_repo, from_branch, to_repo, to_branch)
+
+        def _merge_stratum(si):
+            if si['repo'] == root_repo:
+                to_repo = to_root_dir
+            else:
+                from_repo = self.find_repository(from_branch_dir, si['repo'])
+                to_repo = self.make_repository_available(
+                    to_branch, to_branch_dir, si['repo'], to_branch)
+                self.merge_repo(
+                    si['repo'], from_repo, from_branch, to_repo, to_branch,
+                    is_morphs_repo=True)
+                # We will do a merge commit in this repo later on
+                morphs_repo_list.add(to_repo)
+
+            stratum = self.load_morphology(to_repo, si['morph'])
+            for ci in stratum['chunks']:
+                if ci['ref'] == from_branch:
+                    _merge_chunk(ci)
+                    ci['ref'] = to_branch
+            self.save_morphology(to_repo, si['morph'], stratum)
+
+        from_root_dir = self.find_repository(from_branch_dir, root_repo)
+        to_root_dir = self.find_repository(to_branch_dir, root_repo)
+        self.app.runcmd(['git', 'checkout', to_branch], cwd=to_root_dir)
+        self.merge_repo(root_repo, from_root_dir, from_branch, to_root_dir,
+                        to_branch, is_morphs_repo = True)
+        morphs_repo_list = set([to_root_dir])
+
+        for f in glob.glob(os.path.join(to_root_dir, '*.morph')):
+            name = f[:-len('.morph')]
+            morphology = self.load_morphology(to_root_dir, name)
+
+            if morphology['kind'] == 'system':
+                for si in morphology['strata']:
+                    if si['ref'] == from_branch:
+                        _merge_stratum(si)
+                    si['ref'] = to_branch
+                self.save_morphology(to_root_dir, name, morphology)
+
+        for repo in morphs_repo_list:
+            msg = "Merge system branch '%s'" % from_branch
+            self.app.runcmd(['git', 'commit', '--all', '--message="%s"' % msg],
+                            cwd=repo)
 
     def build(self, args):
         if len(args) != 1:
@@ -674,7 +742,7 @@ class BranchAndMergePlugin(cliapp.Plugin):
         except:
             return None
 
-    def get_uncommitted_changes(self, repo_dir, env):
+    def get_uncommitted_changes(self, repo_dir, env={}):
         status = self.app.runcmd(['git', 'status', '--porcelain'],
                                  cwd=repo_dir, env=env)
         changes = []
diff --git a/tests.branching/merge-explicitly-named-repos.stdout b/tests.branching/merge-explicitly-named-repos.stdout
deleted file mode 100644
index cd2122c4..00000000
--- a/tests.branching/merge-explicitly-named-repos.stdout
+++ /dev/null
@@ -1 +0,0 @@
-newfile.txt
diff --git a/tests.branching/merge-explicitly-named-repos.script b/tests.branching/merge.script
index 7dfd5780..7c433519 100755
--- a/tests.branching/merge-explicitly-named-repos.script
+++ b/tests.branching/merge.script
@@ -14,34 +14,37 @@
 # with this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
-
-# Check that "morph merge" merges explicitly named repositories.
-
+# Check that "morph merge" merges a system branch into master
 
 set -eu
 
-
 # Create system branch.
 cd "$DATADIR/workspace"
 "$SRCDIR/scripts/test-morph" init
-"$SRCDIR/scripts/test-morph" branch baserock:morphs newbranch
+"$SRCDIR/scripts/test-morph" branch baserock:morphs baserock/newbranch
 
 # Make a change to a chunk.
 "$SRCDIR/scripts/test-morph" edit hello-system hello-stratum hello
-cd newbranch/baserock:hello
+cd baserock/newbranch/baserock:hello
 touch newfile.txt
 git add newfile.txt
 git commit -m foo --quiet
 
-# Merge changes to a new system branch.
+# Commit in morphs repo
+cd ../baserock:morphs
+git commit --all --quiet -m "Update morph refs for baserock/newbranch"
+
+# Merge changes back to master
 cd "$DATADIR/workspace"
-"$SRCDIR/scripts/test-morph" branch baserock:morphs otherbranch
-cd otherbranch
-"$SRCDIR/scripts/test-morph" edit hello-system hello-stratum hello
-"$SRCDIR/scripts/test-morph" merge newbranch baserock:hello
+"$SRCDIR/scripts/test-morph" checkout baserock:morphs master
+cd master
+"$SRCDIR/scripts/test-morph" merge baserock/newbranch
 
 # Check results.
 cd baserock:hello
 git status --short # make sure all changes are committed
-ls newfile.txt # make sure the new file is there
+[ -e newfile.txt ] # make sure the new file is there
 
+# Make sure all refs to the merged branch have gone.
+cd ../baserock:morphs
+! grep "\"ref\": \"baserock/newbranch\"" *.morph
diff --git a/tests.branching/workflow.script b/tests.branching/workflow.script
index cb79c3c5..68da4f4a 100755
--- a/tests.branching/workflow.script
+++ b/tests.branching/workflow.script
@@ -30,9 +30,10 @@ echo > README yoyoyo
 git add README
 git commit -m "Fix README, yo!" --quiet
 
+cd ../baserock:morphs
+git commit --quiet --all -m "Commit changes for system branch"
+
 cd "$DATADIR/workspace"
 "$SRCDIR/scripts/test-morph" checkout baserock:morphs master
 cd master
-"$SRCDIR/scripts/test-morph" edit hello-system hello-stratum hello
-"$SRCDIR/scripts/test-morph" merge me/readme-fix baserock:hello
-
+"$SRCDIR/scripts/test-morph" merge me/readme-fix