Revert 194990 "Second take at handling users with locally overri..."

> Second take at handling users with locally overridden diff-cmds.
> 
> The first take at https://chromiumcodereview.appspot.com/14130006 tried to pass
> "--diff-cmd diff", which doesn't work for e.g. Windows cmd users who don't have
> a "diff" executable installed.
> 
> This take instead passes the "--internal-diff" switch which tells svn to ignore
> any diff-cmd set locally and use its internal diff engine at all times.
> 
> While implementing this I found that the existing code tried to work around this
> problem in a different way, by setting up a bogus config dir.  Since that
> doesn't seem to work for me, and shouldn't be necessary with this patch anyway,
> removed that code.
> 
> Review URL: https://chromiumcodereview.appspot.com/14050007

TBR=pkasting@chromium.org

Review URL: https://codereview.chromium.org/14188030

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@195009 0039d316-1c4b-4281-b951-d872f2087c98

scm.py

@@ -10,6 +10,7 @@ import logging
 import os
 import re
 import sys
+import tempfile
 import time
 from xml.etree import ElementTree
 
@@ -779,19 +780,30 @@ class SVN(object):
     expected relative path.
     full_move means that move or copy operations should completely recreate the
     files, usually in the prospect to apply the patch for a try job."""
+    # If the user specified a custom diff command in their svn config file,
+    # then it'll be used when we do svn diff, which we don't want to happen
+    # since we want the unified diff.  Using --diff-cmd=diff doesn't always
+    # work, since they can have another diff executable in their path that
+    # gives different line endings.  So we use a bogus temp directory as the
+    # config directory, which gets around these problems.
+    bogus_dir = tempfile.mkdtemp()
+    try:
       # Use "svn info" output instead of os.path.isdir because the latter fails
       # when the file is deleted.
       return SVN._DiffItemInternal(
           filename,
           cwd,
           SVN.CaptureLocalInfo([filename], cwd),
+          bogus_dir,
           full_move,
           revision)
+    finally:
+      gclient_utils.RemoveDirectory(bogus_dir)
 
   @staticmethod
-  def _DiffItemInternal(filename, cwd, info, full_move, revision):
+  def _DiffItemInternal(filename, cwd, info, bogus_dir, full_move, revision):
     """Grabs the diff data."""
-    command = ["diff", "--internal-diff", filename]
+    command = ["diff", "--config-dir", bogus_dir, filename]
     if revision:
       command.extend(['--revision', revision])
     data = None
@@ -859,6 +871,14 @@ class SVN(object):
       if os.path.normcase(path).startswith(root):
         return path[len(root):]
       return path
+    # If the user specified a custom diff command in their svn config file,
+    # then it'll be used when we do svn diff, which we don't want to happen
+    # since we want the unified diff.  Using --diff-cmd=diff doesn't always
+    # work, since they can have another diff executable in their path that
+    # gives different line endings.  So we use a bogus temp directory as the
+    # config directory, which gets around these problems.
+    bogus_dir = tempfile.mkdtemp()
+    try:
       # Cleanup filenames
       filenames = [RelativePath(f, root) for f in filenames]
       # Get information about the modified items (files and directories)
@@ -895,13 +915,13 @@ class SVN(object):
               # revision the file was deleted.
               srcinfo = {'Revision': rev}
             if (srcinfo.get('Revision') != rev and
-              SVN.Capture(['diff', '--internal-diff', '-r', '%d:head' % rev,
-                           srcurl], cwd)):
+                SVN.Capture(['diff', '-r', '%d:head' % rev, srcurl], cwd)):
               metaheaders.append("#$ svn cp -r %d %s %s "
                                  "### WARNING: note non-trunk copy\n" %
                                  (rev, src, filename))
             else:
-            metaheaders.append("#$ cp %s %s\n" % (src, filename))
+              metaheaders.append("#$ cp %s %s\n" % (src,
+                                                    filename))
 
         if metaheaders:
           diffs.append("### BEGIN SVN COPY METADATA\n")
@@ -909,8 +929,8 @@ class SVN(object):
           diffs.append("### END SVN COPY METADATA\n")
       # Now ready to do the actual diff.
       for filename in sorted(data.iterkeys()):
-      diffs.append(SVN._DiffItemInternal(filename, cwd, data[filename],
-                                         full_move, revision))
+        diffs.append(SVN._DiffItemInternal(
+            filename, cwd, data[filename], bogus_dir, full_move, revision))
       # Use StringIO since it can be messy when diffing a directory move with
       # full_move=True.
       buf = cStringIO.StringIO()
@@ -919,6 +939,8 @@ class SVN(object):
       result = buf.getvalue()
       buf.close()
       return result
+    finally:
+      gclient_utils.RemoveDirectory(bogus_dir)
 
   @staticmethod
   def GetEmail(cwd):