chore: deprecate apply-patches in favour of git-{import,export}-patches (#15300)

script/git-export-patches

@@ -0,0 +1,126 @@
+#!/usr/bin/env python
+
+import argparse
+import os
+import re
+import subprocess
+import sys
+
+
+def guess_base_commit(repo):
+  """Guess which commit the patches might be based on"""
+  args = [
+    'git',
+    '-C',
+    repo,
+    'describe',
+    '--tags',
+  ]
+  return subprocess.check_output(args).split('-')[0:2]
+
+
+def format_patch(repo, since):
+  args = [
+    'git',
+    '-C',
+    repo,
+    'format-patch',
+    '--keep-subject',
+    '--no-stat',
+    '--stdout',
+
+    # The name of the parent commit object isn't useful information in this
+    # context, so zero it out to avoid needless patch-file churn.
+    '--zero-commit',
+
+    # Some versions of git print out different numbers of characters in the
+    # 'index' line of patches, so pass --full-index to get consistent
+    # behaviour.
+    '--full-index',
+    since
+  ]
+  return subprocess.check_output(args)
+
+
+def split_patches(patch_data):
+  """Split a concatenated series of patches into N separate patches"""
+  patches = []
+  patch_start = re.compile('^From [0-9a-f]+ ')
+  for line in patch_data.splitlines():
+    if patch_start.match(line):
+      patches.append([])
+    patches[-1].append(line)
+  return patches
+
+
+def munge_subject_to_filename(subject):
+  """Derive a suitable filename from a commit's subject"""
+  if subject.endswith('.patch'):
+    subject = subject[:-6]
+  return re.sub(r'[^A-Za-z0-9-]+', '_', subject).strip('_').lower() + '.patch'
+
+
+def get_file_name(patch):
+  """Return the name of the file to which the patch should be written"""
+  for line in patch:
+    if line.startswith('Patch-Filename: '):
+      return line[len('Patch-Filename: '):]
+  # If no patch-filename header, munge the subject.
+  for line in patch:
+    if line.startswith('Subject: '):
+      return munge_subject_to_filename(line[len('Subject: '):])
+
+
+def remove_patch_filename(patch):
+  """Strip out the Patch-Filename trailer from a patch's message body"""
+  force_keep_next_line = False
+  for i, l in enumerate(patch):
+    is_patchfilename = l.startswith('Patch-Filename: ')
+    next_is_patchfilename = i < len(patch) - 1 and patch[i+1].startswith('Patch-Filename: ')
+    if not force_keep_next_line and (is_patchfilename or (next_is_patchfilename and len(l.rstrip()) == 0)):
+      pass # drop this line
+    else:
+      yield l
+    force_keep_next_line = l.startswith('Subject: ')
+
+
+def main(argv):
+  parser = argparse.ArgumentParser()
+  parser.add_argument("-o", "--output",
+      help="directory into which exported patches will be written")
+  parser.add_argument("patch_range",
+      nargs='?',
+      help="range of patches to export. Defaults to all commits since the "
+           "most recent tag or remote branch.")
+  args = parser.parse_args(argv)
+
+  repo = '.'
+  patch_range = args.patch_range
+  if patch_range is None:
+    patch_range, num_patches = guess_base_commit(repo)
+    sys.stderr.write("Exporting {} patches since {}\n".format(num_patches, patch_range))
+  patch_data = format_patch(repo, patch_range)
+  patches = split_patches(patch_data)
+
+  out_dir = args.output
+  try:
+    os.mkdir(out_dir)
+  except OSError:
+    pass
+
+  # remove old patches, so that deleted commits are correctly reflected in the
+  # patch files (as a removed file)
+  for p in os.listdir(out_dir):
+    if p.endswith('.patch'):
+      os.remove(os.path.join(out_dir, p))
+
+  with open(os.path.join(out_dir, '.patches'), 'w') as pl:
+    for patch in patches:
+      filename = get_file_name(patch)
+      with open(os.path.join(out_dir, filename), 'w') as f:
+        f.write('\n'.join(remove_patch_filename(patch)))
+      pl.write(filename + '\n')
+
+
+if __name__ == '__main__':
+  main(sys.argv[1:])