Re-implement "morph checkout" using new infrastructure

2 files changed, 99 insertions, 37 deletions

diff --git a/morphlib/plugins/branch_and_merge_new_plugin.py b/morphlib/plugins/branch_and_merge_new_plugin.py
index fb3be920..353f0bcc 100644
--- a/morphlib/plugins/branch_and_merge_new_plugin.py
+++ b/morphlib/plugins/branch_and_merge_new_plugin.py
@@ -15,6 +15,9 @@
 
 
 import cliapp
+import logging
+import os
+import shutil
 
 import morphlib
 
@@ -26,6 +29,8 @@ class SimpleBranchAndMergePlugin(cliapp.Plugin):
     def enable(self):
         self.app.add_subcommand('init', self.init, arg_synopsis='[DIR]')
         self.app.add_subcommand('workspace', self.workspace, arg_synopsis='')
+        self.app.add_subcommand(
+            'checkout', self.checkout, arg_synopsis='REPO BRANCH')
 
     def disable(self):
         pass
@@ -68,3 +73,97 @@ class SimpleBranchAndMergePlugin(cliapp.Plugin):
         ws = morphlib.workspace.open('.')
         self.app.output.write('%s\n' % ws.root)
 
+    def checkout(self, args):
+        '''Check out an existing system branch.
+
+        Command line arguments:
+
+        * `REPO` is the URL to the repository to the root repository of
+          a system branch.
+        * `BRANCH` is the name of the system branch.
+
+        This will check out an existing system branch to an existing
+        workspace.  You must create the workspace first. This only checks
+        out the root repository, not the repositories for individual
+        components. You need to use `morph edit` to check out those.
+
+        Example:
+
+            cd /src/workspace
+            morph checkout baserock:baserock/morphs master
+
+        '''
+
+        if len(args) != 2:
+            raise cliapp.AppException('morph checkout needs a repo and the '
+                                      'name of a branch as parameters')
+
+        root_url = args[0]
+        system_branch = args[1]
+
+        self._require_git_user_config()
+
+        # Open the workspace first thing, so user gets a quick error if
+        # we're not inside a workspace.
+        ws = morphlib.workspace.open('.')
+
+        # Make sure the root repository is in the local git repository
+        # cache, and is up to date.
+        lrc, rrc = morphlib.util.new_repo_caches(self.app)
+        cached_repo = lrc.get_updated_repo(root_url)
+
+        # Check the git branch exists.
+        cached_repo.resolve_ref(system_branch)
+
+        root_dir = ws.get_default_system_branch_directory_name(system_branch)
+
+        try:
+            # Create the system branch directory. This doesn't yet clone
+            # the root repository there.
+            sb = morphlib.sysbranchdir.create(
+                root_dir, root_url, system_branch)
+
+            gd = sb.clone_cached_repo(
+                cached_repo, system_branch, system_branch)
+            gd.update_submodules(self.app)
+            gd.update_remotes()
+        except BaseException as e:
+            # Oops. Clean up.
+            logging.error('Caught exception: %s' % str(e))
+            logging.info('Removing half-finished branch %s' % system_branch)
+            self._remove_branch_dir_safe(ws.root, root_dir)
+            raise
+
+    def _remove_branch_dir_safe(self, workspace_root, system_branch_root):
+        # This function avoids throwing any exceptions, so it is safe to call
+        # inside an 'except' block without altering the backtrace.
+
+        def handle_error(function, path, excinfo):
+            logging.warning ("Error while trying to clean up %s: %s" %
+                             (path, excinfo))
+
+        shutil.rmtree(system_branch_root, onerror=handle_error)
+
+        # Remove parent directories that are empty too, avoiding exceptions
+        parent = os.path.dirname(system_branch_root)
+        while parent != os.path.abspath(workspace_root):
+            if len(os.listdir(parent)) > 0 or os.path.islink(parent):
+                break
+            os.rmdir(parent)
+            parent = os.path.dirname(parent)
+
+    def _require_git_user_config(self):
+        '''Warn if the git user.name and user.email variables are not set.'''
+
+        keys = {
+            'user.name': 'My Name',
+            'user.email': 'me@example.com',
+        }
+
+        try:
+            morphlib.git.check_config_set(self.app.runcmd, keys)
+        except morphlib.git.ConfigNotSetException as e:
+            self.app.status(
+                msg="WARNING: %(message)s",
+                message=str(e), error=True)
+
diff --git a/morphlib/plugins/branch_and_merge_plugin.py b/morphlib/plugins/branch_and_merge_plugin.py
index d39f815c..0485f317 100644
--- a/morphlib/plugins/branch_and_merge_plugin.py
+++ b/morphlib/plugins/branch_and_merge_plugin.py
@@ -59,8 +59,6 @@ class BranchAndMergePlugin(cliapp.Plugin):
         # User-facing commands
         self.app.add_subcommand('branch', self.branch,
                                 arg_synopsis='REPO NEW [OLD]')
-        self.app.add_subcommand('checkout', self.checkout,
-                                arg_synopsis='REPO BRANCH')
         self.app.add_subcommand('merge', self.merge,
                                 arg_synopsis='BRANCH')
         self.app.add_subcommand('edit', self.edit,
@@ -623,41 +621,6 @@ class BranchAndMergePlugin(cliapp.Plugin):
         workspace = self.deduce_workspace()
         self._create_branch(workspace, new_branch, repo, commit)
 
-    @warns_git_identity
-    def checkout(self, args):
-        '''Check out an existing system branch.
-
-        Command line arguments:
-
-        * `REPO` is the URL to the repository to the root repository of
-          a system branch.
-        * `BRANCH` is the name of the system branch.
-
-        This will check out an existing system branch to an existing
-        workspace.  You must create the workspace first. This only checks
-        out the root repository, not the repositories for individual
-        components. You need to use `morph edit` to check out those.
-
-        Example:
-
-            cd /src/workspace
-            morph checkout baserock:baserock/morphs master
-
-        '''
-
-        if len(args) != 2:
-            raise cliapp.AppException('morph checkout needs a repo and the '
-                                      'name of a branch as parameters')
-
-        repo = args[0]
-        system_branch = args[1]
-
-        self.lrc, self.rrc = morphlib.util.new_repo_caches(self.app)
-
-        # Create the system branch directory.
-        workspace = self.deduce_workspace()
-        self._create_branch(workspace, system_branch, repo, system_branch)
-
     def checkout_repository(self, branch_dir, repo, ref, parent_ref=None):
         '''Make a chunk or stratum repository available for a system branch