From 509b1985807a308e31bdff595c939503b6d26a40 Mon Sep 17 00:00:00 2001
From: Sam Thursfield <sam.thursfield@codethink.co.uk>
Date: Tue, 4 Nov 2014 12:56:53 +0000
Subject: Only search for repository root in GitDirectory constructor if told
 to

The GitDirectory() constructor, if passed a 'dirname' that doesn't
contain a '.git' subdirectory, can search upwards to find the real root
of the repository. This is used by the `add-binary`, `push`, and `pull`
commands.

This causes very confusing behaviour in the case that 'dirname' points to
a directory that should be a Git repository, but isn't, and that directory
is a path inside the working tree of another Git repository. Rather than
raising an error, in this case the GitDirectory class would perform
operations on a different repository to the one the caller expected.

This 'search_for_root' behaviour is now opt-in, to avoid confusion.
---
 morphlib/gitdir.py                    | 19 +++++++++++++------
 morphlib/gitdir_tests.py              | 10 ++++++++++
 morphlib/plugins/add_binary_plugin.py |  2 +-
 morphlib/plugins/push_pull_plugin.py  |  4 ++--
 4 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/morphlib/gitdir.py b/morphlib/gitdir.py
index 9fef4f1e..a9837030 100644
--- a/morphlib/gitdir.py
+++ b/morphlib/gitdir.py
@@ -352,12 +352,19 @@ class GitDirectory(object):
 
     '''
 
-    def __init__(self, dirname):
-        self.dirname = morphlib.util.find_root(dirname, '.git')
-        # if we are in a bare repo, self.dirname will now be None
-        # so we just use the provided dirname
-        if not self.dirname:
-            self.dirname = dirname
+    def __init__(self, dirname, search_for_root=False):
+        '''Set up a GitDirectory instance for the repository at 'dirname'.
+
+        If 'search_for_root' is set to True, 'dirname' may point to a
+        subdirectory inside the working tree of repository. Otherwise 'dirname'
+        must be the top directory.
+
+        '''
+
+        if search_for_root:
+            dirname = morphlib.util.find_root(dirname, '.git')
+
+        self.dirname = dirname
         self._config = {}
 
     def _runcmd(self, argv, **kwargs):
diff --git a/morphlib/gitdir_tests.py b/morphlib/gitdir_tests.py
index 456e3716..42118fe2 100644
--- a/morphlib/gitdir_tests.py
+++ b/morphlib/gitdir_tests.py
@@ -43,6 +43,16 @@ class GitDirectoryTests(unittest.TestCase):
         gitdir = morphlib.gitdir.GitDirectory(self.dirname)
         self.assertEqual(gitdir.dirname, self.dirname)
 
+    def test_can_search_for_top_directory(self):
+        self.fake_git_clone()
+
+        path_inside_working_tree = os.path.join(self.dirname, 'a', 'b', 'c')
+        os.makedirs(path_inside_working_tree)
+
+        gitdir = morphlib.gitdir.GitDirectory(
+            path_inside_working_tree, search_for_root=True)
+        self.assertEqual(gitdir.dirname, self.dirname)
+
     def test_runs_command_in_right_directory(self):
         self.fake_git_clone()
         gitdir = morphlib.gitdir.GitDirectory(self.dirname)
diff --git a/morphlib/plugins/add_binary_plugin.py b/morphlib/plugins/add_binary_plugin.py
index a192f792..dee1d9c4 100644
--- a/morphlib/plugins/add_binary_plugin.py
+++ b/morphlib/plugins/add_binary_plugin.py
@@ -56,7 +56,7 @@ class AddBinaryPlugin(cliapp.Plugin):
         if not binaries:
             raise morphlib.Error('add-binary must get at least one argument')
 
-        gd = morphlib.gitdir.GitDirectory(os.getcwd())
+        gd = morphlib.gitdir.GitDirectory(os.getcwd(), search_for_root=True)
         gd.fat_init()
         if not gd.has_fat():
             self._make_gitfat(gd)
diff --git a/morphlib/plugins/push_pull_plugin.py b/morphlib/plugins/push_pull_plugin.py
index 843de1a6..ddc9a8af 100644
--- a/morphlib/plugins/push_pull_plugin.py
+++ b/morphlib/plugins/push_pull_plugin.py
@@ -52,7 +52,7 @@ class PushPullPlugin(cliapp.Plugin):
         if len(args) != 2:
             raise morphlib.Error('push must get exactly two arguments')
 
-        gd = morphlib.gitdir.GitDirectory(os.getcwd())
+        gd = morphlib.gitdir.GitDirectory(os.getcwd(), search_for_root=True)
         remote, branch = args
         rs = morphlib.gitdir.RefSpec(branch)
         gd.get_remote(remote).push(rs)
@@ -81,7 +81,7 @@ class PushPullPlugin(cliapp.Plugin):
         if len(args) > 1:
             raise morphlib.Error('pull takes at most one argument')
 
-        gd = morphlib.gitdir.GitDirectory(os.getcwd())
+        gd = morphlib.gitdir.GitDirectory(os.getcwd(), search_for_root=True)
         remote = gd.get_remote('origin')
         if args:
             branch = args[0]
-- 
cgit v1.2.1