Add support for diffing against root commit

doc/source/changes.rst

@@ -4,6 +4,9 @@ Changelog
 
 1.0.3 - Fixes
 =============
+
+* `Commit.diff()` now supports diffing the root commit via `Commit.diff(NULL_TREE)`.
+* `Repo.blame()` now respects `incremental=True`, supporting incremental blames.  Incremental blames are slightly faster since they don't include the file's contents in them.
 * IMPORTANT: This release drops support for python 2.6, which is officially deprecated by the python maintainers.
 
 1.0.2 - Fixes

git/compat.py

@@ -8,7 +8,6 @@
 # flake8: noqa
 
 import sys
-import six
 
 from gitdb.utils.compat import (
     PY3,
@@ -34,6 +33,7 @@ def bchr(n):
         return bytes([n])
     def mviter(d):
         return d.values()
+    range = xrange
     unicode = str
 else:
     FileType = file
@@ -44,21 +44,17 @@ def mviter(d):
     byte_ord = ord
     bchr = chr
     unicode = unicode
+    range = xrange
     def mviter(d):
         return d.itervalues()
 
-PRE_PY27 = sys.version_info < (2, 7)
-
 
 def safe_decode(s):
     """Safely decodes a binary string to unicode"""
-    if isinstance(s, six.text_type):
+    if isinstance(s, unicode):
         return s
-    elif isinstance(s, six.binary_type):
-        if PRE_PY27:
-            return s.decode(defenc)  # we're screwed
-        else:
-            return s.decode(defenc, errors='replace')
+    elif isinstance(s, bytes):
+        return s.decode(defenc, errors='replace')
     raise TypeError('Expected bytes or text, but got %r' % (s,))
 
 

git/diff.py

@@ -16,7 +16,10 @@
 )
 
 
-__all__ = ('Diffable', 'DiffIndex', 'Diff')
+__all__ = ('Diffable', 'DiffIndex', 'Diff', 'NULL_TREE')
+
+# Special object to compare against the empty tree in diffs
+NULL_TREE = object()
 
 
 class Diffable(object):
@@ -49,6 +52,7 @@ def diff(self, other=Index, paths=None, create_patch=False, **kwargs):
             If None, we will be compared to the working tree.
             If Treeish, it will be compared against the respective tree
             If Index ( type ), it will be compared against the index.
+            If git.NULL_TREE, it will compare against the empty tree.
             It defaults to Index to assure the method will not by-default fail
             on bare repositories.
 
@@ -87,10 +91,17 @@ def diff(self, other=Index, paths=None, create_patch=False, **kwargs):
         if paths is not None and not isinstance(paths, (tuple, list)):
             paths = [paths]
 
-        if other is not None and other is not self.Index:
-            args.insert(0, other)
+        diff_cmd = self.repo.git.diff
         if other is self.Index:
-            args.insert(0, "--cached")
+            args.insert(0, '--cached')
+        elif other is NULL_TREE:
+            args.insert(0, '-r')  # recursive diff-tree
+            args.insert(0, '--root')
+            diff_cmd = self.repo.git.diff_tree
+        elif other is not None:
+            args.insert(0, '-r')  # recursive diff-tree
+            args.insert(0, other)
+            diff_cmd = self.repo.git.diff_tree
 
         args.insert(0, self)
 
@@ -101,7 +112,7 @@ def diff(self, other=Index, paths=None, create_patch=False, **kwargs):
         # END paths handling
 
         kwargs['as_process'] = True
-        proc = self.repo.git.diff(*self._process_diff_args(args), **kwargs)
+        proc = diff_cmd(*self._process_diff_args(args), **kwargs)
 
         diff_method = Diff._index_from_raw_format
         if create_patch:

git/repo/base.py

@@ -54,12 +54,12 @@
     defenc,
     PY3,
     safe_decode,
+    range,
 )
 
 import os
 import sys
 import re
-from six.moves import range
 
 DefaultDBType = GitCmdObjectDB
 if sys.version_info[:2] < (2, 5):     # python 2.4 compatiblity

git/test/fixtures/diff_initial

@@ -0,0 +1,10 @@
+--- /dev/null
++++ b/CHANGES
+@@ -0,0 +1,7 @@
++=======
++CHANGES
++=======
++
++0.1.0
++=====
++initial release

git/test/test_diff.py

@@ -21,7 +21,8 @@
     Repo,
     GitCommandError,
     Diff,
-    DiffIndex
+    DiffIndex,
+    NULL_TREE,
 )
 
 
@@ -128,6 +129,21 @@ def test_diff_index_raw_format(self):
         assert res[0].deleted_file
         assert res[0].b_path == ''
 
+    def test_diff_initial_commit(self):
+        initial_commit = self.rorepo.commit('33ebe7acec14b25c5f84f35a664803fcab2f7781')
+
+        # Without creating a patch...
+        diff_index = initial_commit.diff(NULL_TREE)
+        assert diff_index[0].b_path == 'CHANGES'
+        assert diff_index[0].new_file
+        assert diff_index[0].diff == ''
+
+        # ...and with creating a patch
+        diff_index = initial_commit.diff(NULL_TREE, create_patch=True)
+        assert diff_index[0].b_path == 'CHANGES'
+        assert diff_index[0].new_file
+        assert diff_index[0].diff == fixture('diff_initial')
+
     def test_diff_patch_format(self):
         # test all of the 'old' format diffs for completness - it should at least
         # be able to deal with it
@@ -149,7 +165,7 @@ def test_diff_interface(self):
                 diff_item = commit.tree
             # END use tree every second item
 
-            for other in (None, commit.Index, commit.parents[0]):
+            for other in (None, NULL_TREE, commit.Index, commit.parents[0]):
                 for paths in (None, "CHANGES", ("CHANGES", "lib")):
                     for create_patch in range(2):
                         diff_index = diff_item.diff(other=other, paths=paths, create_patch=create_patch)

tox.ini

@@ -1,10 +1,11 @@
 [tox]
-envlist = py26,py27,py33,py34,flake8
+envlist = py26,py27,py33,py34,py35,flake8
 
 [testenv]
 commands = nosetests {posargs}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
+passenv = HOME
 
 [testenv:cover]
 commands = nosetests --with-coverage {posargs}