Improve git cl split

This CL changes the behavior of `git cl split` to split the change
by the size of the resulting CLs. For now, this is based on the number
of bytes changed, and not by the number of changed lines. Depending
on the shape of change, this may still produce more CLs than expected
(and possibly more than before).

A future change will switch the split to be based on the number
of affected lines, and also introduce a mode to base the split
on the number of affected files.

Bug: 998922
Change-Id: I49f868972a61b89b426ef9e2ceedc733eacb4350
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1778744
Commit-Queue: Yannic Bonenberger <yannic.bonenberger@gmail.com>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>

git_cl.py

@@ -4530,8 +4530,10 @@ def CMDsplit(parser, args):
 
   Creates a branch and uploads a CL for each group of files modified in the
   current branch that share a common OWNERS file. In the CL description and
-  comment, the string '$directory', is replaced with the directory containing
-  the shared OWNERS file.
+  comment, '$directory' is replaced with the directory containing the changes
+  in this CL, '$cl_index' is replaced with the index of the CL we're currently
+  sending out, and '$num_cls' is replaced with the total number of CLs that
+  we're sending out in this split.
   """
   parser.add_option('-d', '--description', dest='description_file',
                     help='A text file containing a CL description in which '

presubmit_support.py

@@ -880,6 +880,22 @@ class _GitDiffCache(_DiffCache):
     return scm.GIT.GetOldContents(local_root, path, branch=self._upstream)
 
 
+def _ParseDiffHeader(line):
+  """Searches |line| for diff headers and returns a tuple
+  (header, old_line, old_size, new_line, new_size), or None if line doesn't
+  contain a diff header.
+
+  This relies on the scm diff output describing each changed code section
+  with a line of the form
+
+  ^@@ <old line num>,<old size> <new line num>,<new size> @@$
+  """
+  m = re.match(r'^@@ \-([0-9]+)\,([0-9]+) \+([0-9]+)\,([0-9]+) @@', line)
+  if m:
+    return (m.group(0), int(m.group(1)), int(m.group(2)), int(m.group(3)),
+            int(m.group(4)))
+
+
 class AffectedFile(object):
   """Representation of a file in a change."""
 
@@ -893,6 +909,7 @@ class AffectedFile(object):
     self._local_root = repository_root
     self._is_directory = None
     self._cached_changed_contents = None
+    self._cached_change_size_in_bytes = None
     self._cached_new_contents = None
     self._diff_cache = diff_cache
     logging.debug('%s(%s)', self.__class__.__name__, self._path)
@@ -969,9 +986,9 @@ class AffectedFile(object):
     line_num = 0
 
     for line in self.GenerateScmDiff().splitlines():
-      m = re.match(r'^@@ [0-9\,\+\-]+ \+([0-9]+)\,[0-9]+ @@', line)
-      if m:
-        line_num = int(m.groups(1)[0])
+      h = _ParseDiffHeader(line)
+      if h:
+        line_num = h[3]
         continue
       if line.startswith('+') and not line.startswith('++'):
         self._cached_changed_contents.append((line_num, line[1:]))
@@ -979,6 +996,25 @@ class AffectedFile(object):
         line_num += 1
     return self._cached_changed_contents[:]
 
+  def ChangeSizeInBytes(self):
+    """Returns a list of tuples (deleted bytes, added bytes) of all changes
+    in this file.
+
+     This relies on the scm diff output describing each changed code section
+     with a line of the form
+
+     ^@@ <old line num>,<old size> <new line num>,<new size> @@$
+    """
+    if self._cached_change_size_in_bytes is not None:
+      return self._cached_change_size_in_bytes[:]
+    self._cached_change_size_in_bytes = []
+
+    for line in self.GenerateScmDiff().splitlines():
+      h = _ParseDiffHeader(line)
+      if h:
+        self._cached_change_size_in_bytes.append((h[2], h[4]))
+    return self._cached_change_size_in_bytes[:]
+
   def __str__(self):
     return self.LocalPath()
 

third_party/pygtrie/README.chromium

+URL: https://github.com/google/pygtrie
+Version: 64ee0836f41a59919ecf8a59b0c7e2f7f1b8c5ba
+License: Apache 2.0
+License File: LICENSE
+
+Description:
+This directory contains the Python pygtrie module.
+
+Local Modifications:
+None