golden hour

/usr/lib/python3/dist-packages/DistUpgrade

File/Folder	Size	Actions
DistUpgradeApport.py	4.95 KB
DistUpgradeAptCdrom.py	12.39 KB
DistUpgradeCache.py	52.93 KB
DistUpgradeConfigParser.py	3.75 KB
DistUpgradeController.py	101.89 KB
DistUpgradeFetcher.py	5.87 KB
DistUpgradeFetcherCore.py	11.2 KB
DistUpgradeFetcherKDE.py	9.72 KB
DistUpgradeFetcherSelf.py	2.02 KB
DistUpgradeGettext.py	2.97 KB
DistUpgradeMain.py	9.1 KB
DistUpgradePatcher.py	3.92 KB
DistUpgradeQuirks.py	49.04 KB
DistUpgradeVersion.py	21 B
DistUpgradeView.py	16.43 KB
DistUpgradeViewGtk3.py	33.85 KB
DistUpgradeViewKDE.py	42.11 KB
DistUpgradeViewNonInteractive.py	13.54 KB
DistUpgradeViewText.py	12.53 KB
GtkProgress.py	3.93 KB
MetaRelease.py	17.06 KB
QUrlOpener.py	3.24 KB
ReleaseNotesViewer.py	7.48 KB
ReleaseNotesViewerWebkit.py	2.91 KB
SimpleGtk3builderApp.py	2.01 KB
SimpleGtkbuilderApp.py	1.99 KB
__init__.py	0 B
__pycache__	-
apt_btrfs_snapshot.py	9.64 KB
apt_clone.py	32.81 KB
dist-upgrade.py	129 B
distro.py	23.15 KB
telemetry.py	3.4 KB
utils.py	17.92 KB
xorg_fix_proprietary.py	3.99 KB

Edit: DistUpgradePatcher.py

# DistUpgradeEdPatcher.py 
#  
#  Copyright (c) 2011 Canonical
#  
#  Author: Michael Vogt <michael.vogt@ubuntu.com>
# 
#  This program is free software; you can redistribute it and/or 
#  modify it under the terms of the GNU General Public License as 
#  published by the Free Software Foundation; either version 2 of the
#  License, or (at your option) any later version.
# 
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
# 
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
#  USA

import hashlib
import re

class PatchError(Exception):
    """ Error during the patch process """
    pass

def patch(orig, edpatch, result_md5sum=None):
    """ python implementation of enough "ed" to apply ed-style
        patches. Note that this patches in memory so its *not*
        suitable for big files
    """

# we only have two states, waiting for command or reading data
    (STATE_EXPECT_COMMAND,
     STATE_EXPECT_DATA) = range(2)

# this is inefficient for big files
    with open(orig, encoding="UTF-8") as f:
        orig_lines = f.readlines()
    start = end = 0

# we start in wait-for-commend state
    state = STATE_EXPECT_COMMAND
    with open(edpatch, encoding="UTF-8") as f:
        lines = f.readlines()
    for line in lines:
        if state == STATE_EXPECT_COMMAND:
            # in commands get rid of whitespace, 
            line = line.strip()
            # check if we have a substitute command
            if line.startswith("s/"):
                # strip away the "s/"
                line = line[2:]
                # chop off the flags at the end 
                subs, flags = line.rsplit("/", 1)
                if flags:
                    raise PatchError("flags for s// not supported yet")
                # get the actual substitution regexp and replacement and 
                # execute it
                regexp, sep, repl = subs.partition("/")
                new, count = re.subn(regexp, repl, orig_lines[start], count=1)
                orig_lines[start] = new
                continue
            # otherwise the last char is the command
            command = line[-1]
            # read address
            (start_str, sep, end_str) = line[:-1].partition(",")
            # ed starts with 1 while python with 0
            start = int(start_str)
            start -= 1
            # if we don't have end, set it to the next line
            if end_str == "":
                end = start + 1
            else:
                end = int(end_str)
            # interpret command
            if command == "c":
                del orig_lines[start:end]
                state = STATE_EXPECT_DATA
                start -= 1
            elif command == "a":
                # not allowed to have a range in append
                state = STATE_EXPECT_DATA
            elif command == "d":
                del orig_lines[start:end]
            else:
                raise PatchError("unknown command: '%s'" % line)
        elif state == STATE_EXPECT_DATA:
            # this is the data end marker
            if line == ".\n":
                state = STATE_EXPECT_COMMAND
            else:
                # copy line verbatim and increase position
                start += 1
                orig_lines.insert(start, line)

# done with the patching, (optional) verify and write result
    result = "".join(orig_lines)
    if result_md5sum:
        md5 = hashlib.md5()
        md5.update(result.encode("UTF-8"))
        if md5.hexdigest() != result_md5sum:
            raise PatchError("the md5sum after patching is not correct")
    with open(orig, "w", encoding="UTF-8") as f:
        f.write(result)
    return True