Removed os.path.realpath invocations as they are not necessary if paths are used consistently.

This will save IOPs, and make the code easier to understand (I suppose).

Related to gitpython-developers#224

Author: Byron

git/index/base.py

@@ -579,8 +579,14 @@ def _entries_for_paths(self, paths, path_rewriter, fprogress, entries):
         entries_added = list()
         if path_rewriter:
             for path in paths:
-                abspath = os.path.abspath(path)
-                gitrelative_path = abspath[len(self.repo.working_tree_dir) + 1:]
+                if os.path.isabs(path):
+                    abspath = path
+                    gitrelative_path = path[len(self.repo.working_tree_dir) + 1:]
+                else:
+                    gitrelative_path = path
+                    abspath = os.path.join(self.repo.working_tree_dir, gitrelative_path)
+                # end obtain relative and absolute paths
+
                 blob = Blob(self.repo, Blob.NULL_BIN_SHA,
                             stat_mode_to_index_mode(os.stat(abspath).st_mode),
                             to_native_path_linux(gitrelative_path))

git/test/lib/helper.py

@@ -63,11 +63,11 @@ def wait(self):
 
 def _mktemp(*args):
     """Wrapper around default tempfile.mktemp to fix an osx issue
-    :note: the OSX special case was removed as it was unclear why that was needed in the first place. It seems 
+    :note: the OSX special case was removed as it was unclear why that was needed in the first place. It seems
     to be just fine without it. However, if we leave this special case, and if TMPDIR is set to something custom,
     prefixing /private/ will lead to incorrect paths on OSX."""
     tdir = tempfile.mktemp(*args)
-    # See :note: above to learn why this is comented out. 
+    # See :note: above to learn why this is comented out.
     # if sys.platform == 'darwin':
     #     tdir = '/private' + tdir
     return tdir

git/test/test_index.py

@@ -501,7 +501,7 @@ def mixed_iterator():
 
         # same file
         entries = index.reset(new_commit).add(
-            [os.path.abspath(os.path.join('lib', 'git', 'head.py'))] * 2, fprogress=self._fprogress_add)
+            [os.path.join(rw_repo.working_tree_dir, 'lib', 'git', 'head.py')] * 2, fprogress=self._fprogress_add)
         self._assert_entries(entries)
         assert entries[0].mode & 0o644 == 0o644
         # would fail, test is too primitive to handle this case