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

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@194990 0039d316-1c4b-4281-b951-d872f2087c98

scm.py

@@ -10,7 +10,6 @@ import logging
 import os
 import re
 import sys
-import tempfile
 import time
 from xml.etree import ElementTree
 
@@ -780,30 +779,19 @@ 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)
+    # 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),
+        full_move,
+        revision)
 
   @staticmethod
-  def _DiffItemInternal(filename, cwd, info, bogus_dir, full_move, revision):
+  def _DiffItemInternal(filename, cwd, info, full_move, revision):
     """Grabs the diff data."""
-    command = ["diff", "--config-dir", bogus_dir, filename]
+    command = ["diff", "--internal-diff", filename]
     if revision:
       command.extend(['--revision', revision])
     data = None
@@ -871,76 +859,66 @@ 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)
-      data = dict([(f, SVN.CaptureLocalInfo([f], root)) for f in filenames])
-      diffs = []
-      if full_move:
-        # Eliminate modified files inside moved/copied directory.
-        for (filename, info) in data.iteritems():
-          if SVN.IsMovedInfo(info) and info.get("Node Kind") == "directory":
-            # Remove files inside the directory.
-            filenames = [f for f in filenames
-                         if not f.startswith(filename + os.path.sep)]
-        for filename in data.keys():
-          if not filename in filenames:
-            # Remove filtered out items.
-            del data[filename]
-      else:
-        metaheaders = []
-        for (filename, info) in data.iteritems():
-          if SVN.IsMovedInfo(info):
-            # for now, the most common case is a head copy,
-            # so let's just encode that as a straight up cp.
-            srcurl = info.get('Copied From URL')
-            file_root = info.get('Repository Root')
-            rev = int(info.get('Copied From Rev'))
-            assert srcurl.startswith(file_root)
-            src = srcurl[len(file_root)+1:]
-            try:
-              srcinfo = SVN.CaptureRemoteInfo(srcurl)
-            except subprocess2.CalledProcessError, e:
-              if not 'Not a valid URL' in e.stderr:
-                raise
-              # Assume the file was deleted. No idea how to figure out at which
-              # revision the file was deleted.
-              srcinfo = {'Revision': rev}
-            if (srcinfo.get('Revision') != rev and
-                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))
-
-        if metaheaders:
-          diffs.append("### BEGIN SVN COPY METADATA\n")
-          diffs.extend(metaheaders)
-          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], bogus_dir, full_move, revision))
-      # Use StringIO since it can be messy when diffing a directory move with
-      # full_move=True.
-      buf = cStringIO.StringIO()
-      for d in filter(None, diffs):
-        buf.write(d)
-      result = buf.getvalue()
-      buf.close()
-      return result
-    finally:
-      gclient_utils.RemoveDirectory(bogus_dir)
+    # Cleanup filenames
+    filenames = [RelativePath(f, root) for f in filenames]
+    # Get information about the modified items (files and directories)
+    data = dict([(f, SVN.CaptureLocalInfo([f], root)) for f in filenames])
+    diffs = []
+    if full_move:
+      # Eliminate modified files inside moved/copied directory.
+      for (filename, info) in data.iteritems():
+        if SVN.IsMovedInfo(info) and info.get("Node Kind") == "directory":
+          # Remove files inside the directory.
+          filenames = [f for f in filenames
+                       if not f.startswith(filename + os.path.sep)]
+      for filename in data.keys():
+        if not filename in filenames:
+          # Remove filtered out items.
+          del data[filename]
+    else:
+      metaheaders = []
+      for (filename, info) in data.iteritems():
+        if SVN.IsMovedInfo(info):
+          # for now, the most common case is a head copy,
+          # so let's just encode that as a straight up cp.
+          srcurl = info.get('Copied From URL')
+          file_root = info.get('Repository Root')
+          rev = int(info.get('Copied From Rev'))
+          assert srcurl.startswith(file_root)
+          src = srcurl[len(file_root)+1:]
+          try:
+            srcinfo = SVN.CaptureRemoteInfo(srcurl)
+          except subprocess2.CalledProcessError, e:
+            if not 'Not a valid URL' in e.stderr:
+              raise
+            # Assume the file was deleted. No idea how to figure out at which
+            # 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)):
+            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))
+
+      if metaheaders:
+        diffs.append("### BEGIN SVN COPY METADATA\n")
+        diffs.extend(metaheaders)
+        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))
+    # Use StringIO since it can be messy when diffing a directory move with
+    # full_move=True.
+    buf = cStringIO.StringIO()
+    for d in filter(None, diffs):
+      buf.write(d)
+    result = buf.getvalue()
+    buf.close()
+    return result
 
   @staticmethod
   def GetEmail(cwd):