From fbcb9bef2922c7b9406daa706253effcbb95b0e5 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 31 Mar 2021 10:09:54 -0400
Subject: [PATCH 01/19] Delete unused code.

---
 src/allmydata/util/sibpath.py |  24 ---
 src/allmydata/util/verlib.py  | 336 ----------------------------------
 2 files changed, 360 deletions(-)
 delete mode 100644 src/allmydata/util/sibpath.py
 delete mode 100644 src/allmydata/util/verlib.py

diff --git a/src/allmydata/util/sibpath.py b/src/allmydata/util/sibpath.py
deleted file mode 100644
index 80a2801a3..000000000
--- a/src/allmydata/util/sibpath.py
+++ /dev/null
@@ -1,24 +0,0 @@
-import os
-import sys
-from twisted.python.util import sibpath as tsibpath
-
-def sibpath(path, sibling):
-    """
-    Looks for a named sibling relative to the given path.  If such a file
-    exists, its path will be returned, otherwise a second search will be
-    made for the named sibling relative to the path of the executable
-    currently running.  This is useful in the case that something built
-    with py2exe, for example, needs to find data files relative to its
-    install.  Note hence that care should be taken not to search for
-    private package files whose names might collide with files which might
-    be found installed alongside the python interpreter itself.  If no
-    file is found in either place, the sibling relative to the given path
-    is returned, likely leading to a file not found error.
-    """
-    sib = tsibpath(path, sibling)
-    if not os.path.exists(sib):
-        exe_sib = tsibpath(sys.executable, sibling)
-        if os.path.exists(exe_sib):
-            return exe_sib
-    return sib
-
diff --git a/src/allmydata/util/verlib.py b/src/allmydata/util/verlib.py
deleted file mode 100644
index 2dfc24a1b..000000000
--- a/src/allmydata/util/verlib.py
+++ /dev/null
@@ -1,336 +0,0 @@
-"""
-"Rational" version definition and parsing for DistutilsVersionFight
-discussion at PyCon 2009.
-
-Ported to Python 3.
-"""
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
-
-from future.utils import PY2
-if PY2:
-    from builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
-
-import re
-
-
-class IrrationalVersionError(Exception):
-    """This is an irrational version."""
-    pass
-
-class HugeMajorVersionNumError(IrrationalVersionError):
-    """An irrational version because the major version number is huge
-    (often because a year or date was used).
-
-    See `error_on_huge_major_num` option in `NormalizedVersion` for details.
-    This guard can be disabled by setting that option False.
-    """
-    pass
-
-# A marker used in the second and third parts of the `parts` tuple, for
-# versions that don't have those segments, to sort properly. An example
-# of versions in sort order ('highest' last):
-#   1.0b1                 ((1,0), ('b',1), ('f',))
-#   1.0.dev345            ((1,0), ('f',),  ('dev', 345))
-#   1.0                   ((1,0), ('f',),  ('f',))
-#   1.0.post256.dev345    ((1,0), ('f',),  ('f', 'post', 256, 'dev', 345))
-#   1.0.post345           ((1,0), ('f',),  ('f', 'post', 345, 'f'))
-#                                   ^        ^                 ^
-#   'b' < 'f' ---------------------/         |                 |
-#                                            |                 |
-#   'dev' < 'f' < 'post' -------------------/                  |
-#                                                              |
-#   'dev' < 'f' ----------------------------------------------/
-# Other letters would do, but 'f' for 'final' is kind of nice.
-FINAL_MARKER = ('f',)
-
-VERSION_RE = re.compile(r'''
-    ^
-    (?P<version>\d+\.\d+)          # minimum 'N.N'
-    (?P<extraversion>(?:\.\d+)*)   # any number of extra '.N' segments
-    (?:
-        (?P<prerel>[abc]|rc)       # 'a'=alpha, 'b'=beta, 'c'=release candidate
-                                   # 'rc'= alias for release candidate
-        (?P<prerelversion>\d+(?:\.\d+)*)
-    )?
-    (?P<postdev>(\.post(?P<post>\d+))?(\.dev(?P<dev>\d+))?)?
-    $''', re.VERBOSE)
-
-class NormalizedVersion(object):
-    """A rational version.
-
-    Good:
-        1.2         # equivalent to "1.2.0"
-        1.2.0
-        1.2a1
-        1.2.3a2
-        1.2.3b1
-        1.2.3c1
-        1.2.3.4
-        TODO: fill this out
-
-    Bad:
-        1           # mininum two numbers
-        1.2a        # release level must have a release serial
-        1.2.3b
-    """
-    def __init__(self, s, error_on_huge_major_num=True):
-        """Create a NormalizedVersion instance from a version string.
-
-        @param s {str} The version string.
-        @param error_on_huge_major_num {bool} Whether to consider an
-            apparent use of a year or full date as the major version number
-            an error. Default True. One of the observed patterns on PyPI before
-            the introduction of `NormalizedVersion` was version numbers like this:
-                2009.01.03
-                20040603
-                2005.01
-            This guard is here to strongly encourage the package author to
-            use an alternate version, because a release deployed into PyPI
-            and, e.g. downstream Linux package managers, will forever remove
-            the possibility of using a version number like "1.0" (i.e.
-            where the major number is less than that huge major number).
-        """
-        self._parse(s, error_on_huge_major_num)
-
-    @classmethod
-    def from_parts(cls, version, prerelease=FINAL_MARKER,
-                   devpost=FINAL_MARKER):
-        return cls(cls.parts_to_str((version, prerelease, devpost)))
-
-    def _parse(self, s, error_on_huge_major_num=True):
-        """Parses a string version into parts."""
-        match = VERSION_RE.search(s)
-        if not match:
-            raise IrrationalVersionError(s)
-
-        groups = match.groupdict()
-        parts = []
-
-        # main version
-        block = self._parse_numdots(groups['version'], s, False, 2)
-        extraversion = groups.get('extraversion')
-        if extraversion not in ('', None):
-            block += self._parse_numdots(extraversion[1:], s)
-        parts.append(tuple(block))
-
-        # prerelease
-        prerel = groups.get('prerel')
-        if prerel is not None:
-            block = [prerel]
-            block += self._parse_numdots(groups.get('prerelversion'), s,
-                                         pad_zeros_length=1)
-            parts.append(tuple(block))
-        else:
-            parts.append(FINAL_MARKER)
-
-        # postdev
-        if groups.get('postdev'):
-            post = groups.get('post')
-            dev = groups.get('dev')
-            postdev = []
-            if post is not None:
-                postdev.extend([FINAL_MARKER[0], 'post', int(post)])
-                if dev is None:
-                    postdev.append(FINAL_MARKER[0])
-            if dev is not None:
-                postdev.extend(['dev', int(dev)])
-            parts.append(tuple(postdev))
-        else:
-            parts.append(FINAL_MARKER)
-        self.parts = tuple(parts)
-        if error_on_huge_major_num and self.parts[0][0] > 1980:
-            raise HugeMajorVersionNumError("huge major version number, %r, "
-                "which might cause future problems: %r" % (self.parts[0][0], s))
-
-    def _parse_numdots(self, s, full_ver_str, drop_trailing_zeros=True,
-                       pad_zeros_length=0):
-        """Parse 'N.N.N' sequences, return a list of ints.
-
-        @param s {str} 'N.N.N...' sequence to be parsed
-        @param full_ver_str {str} The full version string from which this
-            comes. Used for error strings.
-        @param drop_trailing_zeros {bool} Whether to drop trailing zeros
-            from the returned list. Default True.
-        @param pad_zeros_length {int} The length to which to pad the
-            returned list with zeros, if necessary. Default 0.
-        """
-        nums = []
-        for n in s.split("."):
-            if len(n) > 1 and n[0] == '0':
-                raise IrrationalVersionError("cannot have leading zero in "
-                    "version number segment: '%s' in %r" % (n, full_ver_str))
-            nums.append(int(n))
-        if drop_trailing_zeros:
-            while nums and nums[-1] == 0:
-                nums.pop()
-        while len(nums) < pad_zeros_length:
-            nums.append(0)
-        return nums
-
-    def __str__(self):
-        return self.parts_to_str(self.parts)
-
-    @classmethod
-    def parts_to_str(cls, parts):
-        """Transforms a version expressed in tuple into its string
-        representation."""
-        # XXX This doesn't check for invalid tuples
-        main, prerel, postdev = parts
-        s = '.'.join(str(v) for v in main)
-        if prerel is not FINAL_MARKER:
-            s += prerel[0]
-            s += '.'.join(str(v) for v in prerel[1:])
-        if postdev and postdev is not FINAL_MARKER:
-            if postdev[0] == 'f':
-                postdev = postdev[1:]
-            i = 0
-            while i < len(postdev):
-                if i % 2 == 0:
-                    s += '.'
-                s += str(postdev[i])
-                i += 1
-        return s
-
-    def __repr__(self):
-        return "%s('%s')" % (self.__class__.__name__, self)
-
-    def _cannot_compare(self, other):
-        raise TypeError("cannot compare %s and %s"
-                % (type(self).__name__, type(other).__name__))
-
-    def __eq__(self, other):
-        if not isinstance(other, NormalizedVersion):
-            self._cannot_compare(other)
-        return self.parts == other.parts
-
-    def __lt__(self, other):
-        if not isinstance(other, NormalizedVersion):
-            self._cannot_compare(other)
-        return self.parts < other.parts
-
-    def __ne__(self, other):
-        return not self.__eq__(other)
-
-    def __gt__(self, other):
-        return not (self.__lt__(other) or self.__eq__(other))
-
-    def __le__(self, other):
-        return self.__eq__(other) or self.__lt__(other)
-
-    def __ge__(self, other):
-        return self.__eq__(other) or self.__gt__(other)
-
-def suggest_normalized_version(s):
-    """Suggest a normalized version close to the given version string.
-
-    If you have a version string that isn't rational (i.e. NormalizedVersion
-    doesn't like it) then you might be able to get an equivalent (or close)
-    rational version from this function.
-
-    This does a number of simple normalizations to the given string, based
-    on observation of versions currently in use on PyPI. Given a dump of
-    those version during PyCon 2009, 4287 of them:
-    - 2312 (53.93%) match NormalizedVersion without change
-    - with the automatic suggestion
-    - 3474 (81.04%) match when using this suggestion method
-
-    @param s {str} An irrational version string.
-    @returns A rational version string, or None, if couldn't determine one.
-    """
-    try:
-        NormalizedVersion(s)
-        return s   # already rational
-    except IrrationalVersionError:
-        pass
-
-    rs = s.lower()
-
-    # part of this could use maketrans
-    for orig, repl in (('-alpha', 'a'), ('-beta', 'b'), ('alpha', 'a'),
-                       ('beta', 'b'), ('rc', 'c'), ('-final', ''),
-                       ('-pre', 'c'),
-                       ('-release', ''), ('.release', ''), ('-stable', ''),
-                       ('+', '.'), ('_', '.'), (' ', ''), ('.final', ''),
-                       ('final', '')):
-        rs = rs.replace(orig, repl)
-
-    # if something ends with dev or pre, we add a 0
-    rs = re.sub(r"pre$", r"pre0", rs)
-    rs = re.sub(r"dev$", r"dev0", rs)
-
-    # if we have something like "b-2" or "a.2" at the end of the
-    # version, that is pobably beta, alpha, etc
-    # let's remove the dash or dot
-    rs = re.sub(r"([abc]|rc)[\-\.](\d+)$", r"\1\2", rs)
-
-    # 1.0-dev-r371 -> 1.0.dev371
-    # 0.1-dev-r79 -> 0.1.dev79
-    rs = re.sub(r"[\-\.](dev)[\-\.]?r?(\d+)$", r".\1\2", rs)
-
-    # Clean: 2.0.a.3, 2.0.b1, 0.9.0~c1
-    rs = re.sub(r"[.~]?([abc])\.?", r"\1", rs)
-
-    # Clean: v0.3, v1.0
-    if rs.startswith('v'):
-        rs = rs[1:]
-
-    # Clean leading '0's on numbers.
-    #TODO: unintended side-effect on, e.g., "2003.05.09"
-    # PyPI stats: 77 (~2%) better
-    rs = re.sub(r"\b0+(\d+)(?!\d)", r"\1", rs)
-
-    # Clean a/b/c with no version. E.g. "1.0a" -> "1.0a0". Setuptools infers
-    # zero.
-    # PyPI stats: 245 (7.56%) better
-    rs = re.sub(r"(\d+[abc])$", r"\g<1>0", rs)
-
-    # the 'dev-rNNN' tag is a dev tag
-    rs = re.sub(r"\.?(dev-r|dev\.r)\.?(\d+)$", r".dev\2", rs)
-
-    # clean the - when used as a pre delimiter
-    rs = re.sub(r"-(a|b|c)(\d+)$", r"\1\2", rs)
-
-    # a terminal "dev" or "devel" can be changed into ".dev0"
-    rs = re.sub(r"[\.\-](dev|devel)$", r".dev0", rs)
-
-    # a terminal "dev" can be changed into ".dev0"
-    rs = re.sub(r"(?![\.\-])dev$", r".dev0", rs)
-
-    # a terminal "final" or "stable" can be removed
-    rs = re.sub(r"(final|stable)$", "", rs)
-
-    # The 'r' and the '-' tags are post release tags
-    #   0.4a1.r10       ->  0.4a1.post10
-    #   0.9.33-17222    ->  0.9.33.post17222
-    #   0.9.33-r17222   ->  0.9.33.post17222
-    rs = re.sub(r"\.?(r|-|-r)\.?(\d+)$", r".post\2", rs)
-
-    # Clean 'r' instead of 'dev' usage:
-    #   0.9.33+r17222   ->  0.9.33.dev17222
-    #   1.0dev123       ->  1.0.dev123
-    #   1.0.git123      ->  1.0.dev123
-    #   1.0.bzr123      ->  1.0.dev123
-    #   0.1a0dev.123    ->  0.1a0.dev123
-    # PyPI stats:  ~150 (~4%) better
-    rs = re.sub(r"\.?(dev|git|bzr)\.?(\d+)$", r".dev\2", rs)
-
-    # Clean '.pre' (normalized from '-pre' above) instead of 'c' usage:
-    #   0.2.pre1        ->  0.2c1
-    #   0.2-c1         ->  0.2c1
-    #   1.0preview123   ->  1.0c123
-    # PyPI stats: ~21 (0.62%) better
-    rs = re.sub(r"\.?(pre|preview|-c)(\d+)$", r"c\g<2>", rs)
-
-
-    # Tcl/Tk uses "px" for their post release markers
-    rs = re.sub(r"p(\d+)$", r".post\1", rs)
-
-    try:
-        NormalizedVersion(rs)
-        return rs   # already rational
-    except IrrationalVersionError:
-        pass
-    return None

From 1ead68d06128960c16dfda77413cafc4045e79d6 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 31 Mar 2021 10:10:05 -0400
Subject: [PATCH 02/19] Start of tests for consumer.py.

---
 src/allmydata/test/test_consumer.py | 80 +++++++++++++++++++++++++++++
 src/allmydata/util/_python3.py      |  1 +
 2 files changed, 81 insertions(+)
 create mode 100644 src/allmydata/test/test_consumer.py

diff --git a/src/allmydata/test/test_consumer.py b/src/allmydata/test/test_consumer.py
new file mode 100644
index 000000000..98f419764
--- /dev/null
+++ b/src/allmydata/test/test_consumer.py
@@ -0,0 +1,80 @@
+"""
+Tests for allmydata.util.consumer.
+
+Ported to Python 3.
+"""
+
+from __future__ import unicode_literals
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
+
+from zope.interface import implementer
+from twisted.trial.unittest import TestCase
+from twisted.internet.interfaces import IPushProducer, IPullProducer
+
+from allmydata.util.consumer import MemoryConsumer, download_to_data
+
+
+@implementer(IPushProducer)
+@implementer(IPullProducer)
+class Producer:
+    """Can be used as either streaming or non-streaming producer.
+
+    If used as streaming, the test should call iterate() manually.
+    """
+
+    def __init__(self, consumer):
+        self.data = [b"abc", b"def", b"ghi"]
+        self.consumer = consumer
+        self.done = False
+
+    def resumeProducing(self):
+        """Kick off streaming."""
+        self.iterate()
+
+    def iterate(self):
+        """Do another iteration of writing."""
+        if self.done:
+            raise RuntimeError(
+                "There's a bug somewhere, shouldn't iterate after being done"
+            )
+        if self.data:
+            self.consumer.write(self.data.pop(0))
+        else:
+            self.done = True
+            self.consumer.unregisterProducer()
+
+
+class MemoryConsumerTests(TestCase):
+    """Tests for MemoryConsumer."""
+
+    def test_push_producer(self):
+        """
+        A MemoryConsumer accumulates all data sent by a streaming producer.
+        """
+        consumer = MemoryConsumer()
+        producer = Producer(consumer)
+        consumer.registerProducer(producer, True)
+        self.assertEqual(consumer.chunks, [b"abc"])
+        producer.iterate()
+        producer.iterate()
+        self.assertEqual(consumer.chunks, [b"abc", b"def", b"ghi"])
+        self.assertEqual(consumer.done, False)
+        producer.iterate()
+        self.assertEqual(consumer.chunks, [b"abc", b"def", b"ghi"])
+        self.assertEqual(consumer.done, True)
+
+    def test_pull_producer(self):
+        """
+        A MemoryConsumer accumulates all data sent by a non-streaming producer.
+        """
+        consumer = MemoryConsumer()
+        producer = Producer(consumer)
+        consumer.registerProducer(producer, False)
+        self.assertEqual(consumer.chunks, [b"abc", b"def", b"ghi"])
+        self.assertEqual(consumer.done, True)
diff --git a/src/allmydata/util/_python3.py b/src/allmydata/util/_python3.py
index 2f6857cad..61c444dc1 100644
--- a/src/allmydata/util/_python3.py
+++ b/src/allmydata/util/_python3.py
@@ -191,6 +191,7 @@ PORTED_TEST_MODULES = [
     "allmydata.test.test_configutil",
     "allmydata.test.test_connections",
     "allmydata.test.test_connection_status",
+    "allmydata.test.test_consumer",
     "allmydata.test.test_crawler",
     "allmydata.test.test_crypto",
 

From 1ef33d3d69de4a66ef70eb9451ddeb149ef69c7f Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 31 Mar 2021 10:50:50 -0400
Subject: [PATCH 03/19] Note download_to_data() is tested elsewhere.

---
 src/allmydata/test/test_consumer.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/allmydata/test/test_consumer.py b/src/allmydata/test/test_consumer.py
index 98f419764..b6c1d1d28 100644
--- a/src/allmydata/test/test_consumer.py
+++ b/src/allmydata/test/test_consumer.py
@@ -78,3 +78,7 @@ class MemoryConsumerTests(TestCase):
         consumer.registerProducer(producer, False)
         self.assertEqual(consumer.chunks, [b"abc", b"def", b"ghi"])
         self.assertEqual(consumer.done, True)
+
+
+# download_to_data() is effectively tested by some of the filenode tests, e.g.
+# test_immutable.py.

From 8439f2820bf00902b185f749c36f5ea7ec9cd643 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 31 Mar 2021 10:53:02 -0400
Subject: [PATCH 04/19] Port to Python 3.

---
 src/allmydata/util/_python3.py |  1 +
 src/allmydata/util/consumer.py | 18 +++++++++++++++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/allmydata/util/_python3.py b/src/allmydata/util/_python3.py
index 61c444dc1..e3fee8dc6 100644
--- a/src/allmydata/util/_python3.py
+++ b/src/allmydata/util/_python3.py
@@ -115,6 +115,7 @@ PORTED_MODULES = [
     "allmydata.util.base62",
     "allmydata.util.configutil",
     "allmydata.util.connection_status",
+    "allmydata.util.consumer",
     "allmydata.util.deferredutil",
     "allmydata.util.dictutil",
     "allmydata.util.eliotutil",
diff --git a/src/allmydata/util/consumer.py b/src/allmydata/util/consumer.py
index a8eededcc..3de82974d 100644
--- a/src/allmydata/util/consumer.py
+++ b/src/allmydata/util/consumer.py
@@ -1,11 +1,22 @@
-
-"""This file defines a basic download-to-memory consumer, suitable for use in
-a filenode's read() method. See download_to_data() for an example of its use.
 """
+This file defines a basic download-to-memory consumer, suitable for use in
+a filenode's read() method. See download_to_data() for an example of its use.
+
+Ported to Python 3.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 from zope.interface import implementer
 from twisted.internet.interfaces import IConsumer
 
+
 @implementer(IConsumer)
 class MemoryConsumer(object):
 
@@ -28,6 +39,7 @@ class MemoryConsumer(object):
     def unregisterProducer(self):
         self.done = True
 
+
 def download_to_data(n, offset=0, size=None):
     """
     Return Deferred that fires with results of reading from the given filenode.

From de2609151e2add0b505f62c8644a5e86a79e7117 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 1 Apr 2021 10:01:14 -0400
Subject: [PATCH 05/19] Special logic for roundtripping Unicode to Unicode is
 only necessary on Python 2.

---
 src/allmydata/test/test_util.py |  7 ++++++-
 src/allmydata/util/yamlutil.py  | 29 +++++++++++++++++++++++------
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/src/allmydata/test/test_util.py b/src/allmydata/test/test_util.py
index a14adb787..4dc2793a4 100644
--- a/src/allmydata/test/test_util.py
+++ b/src/allmydata/test/test_util.py
@@ -480,7 +480,12 @@ class EqButNotIs(object):
 
 class YAML(unittest.TestCase):
     def test_convert(self):
-        data = yaml.safe_dump(["str", u"unicode", u"\u1234nicode"])
+        """
+        Unicode and (ASCII) native strings get roundtripped to Unicode strings.
+        """
+        data = yaml.safe_dump(
+            [six.ensure_str("str"), u"unicode", u"\u1234nicode"]
+        )
         back = yamlutil.safe_load(data)
         self.assertIsInstance(back[0], str)
         self.assertIsInstance(back[1], str)
diff --git a/src/allmydata/util/yamlutil.py b/src/allmydata/util/yamlutil.py
index 40c38fa30..f7eb8004f 100644
--- a/src/allmydata/util/yamlutil.py
+++ b/src/allmydata/util/yamlutil.py
@@ -1,11 +1,28 @@
+from future.utils import PY2
+
 import yaml
 
-# Announcements contain unicode, because they come from JSON. We tell PyYAML
-# to give us unicode instead of str/bytes.
-def construct_unicode(loader, node):
-    return node.value
-yaml.SafeLoader.add_constructor("tag:yaml.org,2002:str",
-                                construct_unicode)
+if PY2:
+    # On Python 2 the way pyyaml deals with Unicode strings is inconsistent.
+    #
+    # >>> yaml.safe_load(yaml.safe_dump(u"hello"))
+    # 'hello'
+    # >>> yaml.safe_load(yaml.safe_dump(u"hello\u1234"))
+    # u'hello\u1234'
+    #
+    # In other words, Unicode strings get roundtripped to byte strings, but
+    # only sometimes.
+    #
+    # In order to ensure unicode stays unicode, we add a configuration saying
+    # that the YAML String Language-Independent Type ("a sequence of zero or
+    # more Unicode characters") should be the underlying Unicode string object,
+    # rather than converting to bytes when possible.
+    #
+    # Reference: https://yaml.org/type/str.html
+    def construct_unicode(loader, node):
+        return node.value
+    yaml.SafeLoader.add_constructor("tag:yaml.org,2002:str",
+                                    construct_unicode)
 
 def safe_load(f):
     return yaml.safe_load(f)

From 5ac631047c26fee933d6407f209ea0733fad3a99 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 1 Apr 2021 10:04:01 -0400
Subject: [PATCH 06/19] Port to Python 3.

---
 src/allmydata/util/_python3.py |  1 +
 src/allmydata/util/yamlutil.py | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/src/allmydata/util/_python3.py b/src/allmydata/util/_python3.py
index e3fee8dc6..e8783aee7 100644
--- a/src/allmydata/util/_python3.py
+++ b/src/allmydata/util/_python3.py
@@ -140,6 +140,7 @@ PORTED_MODULES = [
     "allmydata.util.statistics",
     "allmydata.util.time_format",
     "allmydata.util.tor_provider",
+    "allmydata.util.yamlutil",
     "allmydata.web",
     "allmydata.web.check_results",
     "allmydata.web.common",
diff --git a/src/allmydata/util/yamlutil.py b/src/allmydata/util/yamlutil.py
index f7eb8004f..fd9fc73e2 100644
--- a/src/allmydata/util/yamlutil.py
+++ b/src/allmydata/util/yamlutil.py
@@ -1,7 +1,18 @@
+"""
+Ported to Python 3.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 import yaml
 
+
 if PY2:
     # On Python 2 the way pyyaml deals with Unicode strings is inconsistent.
     #

From f606420d7823b29e5fb359d5bf91c87b0d4006f1 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 1 Apr 2021 10:14:05 -0400
Subject: [PATCH 07/19] Make it new-style.

---
 src/allmydata/test/test_consumer.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/allmydata/test/test_consumer.py b/src/allmydata/test/test_consumer.py
index b6c1d1d28..46b87e477 100644
--- a/src/allmydata/test/test_consumer.py
+++ b/src/allmydata/test/test_consumer.py
@@ -22,7 +22,7 @@ from allmydata.util.consumer import MemoryConsumer, download_to_data
 
 @implementer(IPushProducer)
 @implementer(IPullProducer)
-class Producer:
+class Producer(object):
     """Can be used as either streaming or non-streaming producer.
 
     If used as streaming, the test should call iterate() manually.

From 9f02de688ca4baffb1dee7fd3d599d20776c96b7 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 1 Apr 2021 10:19:16 -0400
Subject: [PATCH 08/19] We don't support old Foolscap versions anymore.

---
 src/allmydata/introducer/common.py |  6 ++++--
 src/allmydata/util/rrefutil.py     | 13 -------------
 2 files changed, 4 insertions(+), 15 deletions(-)

diff --git a/src/allmydata/introducer/common.py b/src/allmydata/introducer/common.py
index f67aad203..dd9bb527c 100644
--- a/src/allmydata/introducer/common.py
+++ b/src/allmydata/introducer/common.py
@@ -11,9 +11,11 @@ if PY2:
     from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 import re
+
+from foolscap.api import SturdyRef
 from allmydata.crypto.util import remove_prefix
 from allmydata.crypto import ed25519
-from allmydata.util import base32, rrefutil, jsonbytes as json
+from allmydata.util import base32, jsonbytes as json
 
 
 def get_tubid_string_from_ann(ann):
@@ -127,6 +129,6 @@ class AnnouncementDescriptor(object):
         self.serverid = key_s
         furl = ann_d.get("anonymous-storage-FURL")
         if furl:
-            self.connection_hints = rrefutil.connection_hints_for_furl(furl)
+            self.connection_hints = list(SturdyRef(furl).locationHints)
         else:
             self.connection_hints = []
diff --git a/src/allmydata/util/rrefutil.py b/src/allmydata/util/rrefutil.py
index 40e921507..abcd0e4d2 100644
--- a/src/allmydata/util/rrefutil.py
+++ b/src/allmydata/util/rrefutil.py
@@ -20,19 +20,6 @@ def add_version_to_remote_reference(rref, default):
     return d
 
 
-def connection_hints_for_furl(furl):
-    hints = []
-    for h in SturdyRef(furl).locationHints:
-        # Foolscap-0.2.5 and earlier used strings in .locationHints, 0.2.6
-        # through 0.6.4 used tuples of ("ipv4",host,port), 0.6.5 through
-        # 0.8.0 used tuples of ("tcp",host,port), and >=0.9.0 uses strings
-        # again. Tolerate them all.
-        if isinstance(h, tuple):
-            hints.append(":".join([str(s) for s in h]))
-        else:
-            hints.append(h)
-    return hints
-
 def stringify_remote_address(rref):
     remote = rref.getPeer()
     if isinstance(remote, address.IPv4Address):

From 062740dc23ac43a2d34250e5b574609f06936753 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 1 Apr 2021 10:23:37 -0400
Subject: [PATCH 09/19] Probably not worth unit testing a utility function used
 in one place, move it to place it's used.

---
 src/allmydata/introducer/server.py | 10 ++++++++++
 src/allmydata/util/rrefutil.py     |  9 ---------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/allmydata/introducer/server.py b/src/allmydata/introducer/server.py
index dcc2fd2c0..6d73c4026 100644
--- a/src/allmydata/introducer/server.py
+++ b/src/allmydata/introducer/server.py
@@ -24,6 +24,7 @@ except ImportError:
 from zope.interface import implementer
 from twisted.application import service
 from twisted.internet import defer
+from twisted.internet.address import IPv4Address
 from twisted.python.failure import Failure
 from foolscap.api import Referenceable
 import allmydata
@@ -148,6 +149,15 @@ class _IntroducerNode(node.Node):
         ws = IntroducerWebishServer(self, webport, nodeurl_path, staticdir)
         ws.setServiceParent(self)
 
+
+def stringify_remote_address(rref):
+    remote = rref.getPeer()
+    if isinstance(remote, IPv4Address):
+        return "%s:%d" % (remote.host, remote.port)
+    # loopback is a non-IPv4Address
+    return str(remote)
+
+
 @implementer(RIIntroducerPublisherAndSubscriberService_v2)
 class IntroducerService(service.MultiService, Referenceable):
     name = "introducer"
diff --git a/src/allmydata/util/rrefutil.py b/src/allmydata/util/rrefutil.py
index abcd0e4d2..de0f2fbd5 100644
--- a/src/allmydata/util/rrefutil.py
+++ b/src/allmydata/util/rrefutil.py
@@ -1,5 +1,4 @@
 
-from twisted.internet import address
 from foolscap.api import Violation, RemoteException, SturdyRef
 
 
@@ -18,11 +17,3 @@ def add_version_to_remote_reference(rref, default):
         return rref
     d.addCallbacks(_got_version, _no_get_version)
     return d
-
-
-def stringify_remote_address(rref):
-    remote = rref.getPeer()
-    if isinstance(remote, address.IPv4Address):
-        return "%s:%d" % (remote.host, remote.port)
-    # loopback is a non-IPv4Address
-    return str(remote)

From 6127fc8cc78c9c0c7da492bca48f9a37526dec44 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 1 Apr 2021 10:49:59 -0400
Subject: [PATCH 10/19] Tests for rrefutil.

---
 src/allmydata/test/test_util.py | 39 +++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/src/allmydata/test/test_util.py b/src/allmydata/test/test_util.py
index 4dc2793a4..7b0b52783 100644
--- a/src/allmydata/test/test_util.py
+++ b/src/allmydata/test/test_util.py
@@ -17,12 +17,15 @@ import yaml
 import json
 
 from twisted.trial import unittest
+from twisted.internet import defer
+from foolscap.api import Violation, RemoteException
 
 from allmydata.util import idlib, mathutil
 from allmydata.util import fileutil
 from allmydata.util import jsonbytes
 from allmydata.util import pollmixin
 from allmydata.util import yamlutil
+from allmydata.util import rrefutil
 from allmydata.util.fileutil import EncryptedTemporaryFile
 from allmydata.test.common_util import ReallyEqualMixin
 
@@ -526,3 +529,39 @@ class JSONBytes(unittest.TestCase):
         encoded = jsonbytes.dumps_bytes(x)
         self.assertIsInstance(encoded, bytes)
         self.assertEqual(json.loads(encoded, encoding="utf-8"), x)
+
+
+class FakeRemoteRef(object):
+    """Emulate a RemoteRef."""
+
+    def __init__(self, result):
+        self.result = result
+
+    def callRemote(self, method):
+        assert method == "get_version"
+        if isinstance(self.result, Exception):
+            return defer.fail(self.result)
+        return defer.succeed(self.result)
+
+
+class RrefUtilTests(unittest.TestCase):
+    """Tests for rrefutil."""
+
+    def test_version_returned(self):
+        """If get_version() succeeded, it is set on the rref."""
+        rref = FakeRemoteRef(12345)
+        result = self.successResultOf(
+            rrefutil.add_version_to_remote_reference(rref, "default")
+        )
+        self.assertEqual(result.version, 12345)
+        self.assertIdentical(result, rref)
+
+    def test_exceptions(self):
+        """If get_version() failed, default version is set on the rref."""
+        for exception in (Violation(), RemoteException(ValueError())):
+            rref = FakeRemoteRef(exception)
+            result = self.successResultOf(
+                rrefutil.add_version_to_remote_reference(rref, "Default")
+            )
+            self.assertEqual(result.version, "Default")
+            self.assertIdentical(result, rref)

From e92b88195c6554257602442b83b5a721270811ba Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 1 Apr 2021 10:51:13 -0400
Subject: [PATCH 11/19] Port to Python 3.

---
 src/allmydata/util/_python3.py |  1 +
 src/allmydata/util/rrefutil.py | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/src/allmydata/util/_python3.py b/src/allmydata/util/_python3.py
index e8783aee7..56d9e6aec 100644
--- a/src/allmydata/util/_python3.py
+++ b/src/allmydata/util/_python3.py
@@ -136,6 +136,7 @@ PORTED_MODULES = [
     "allmydata.util.observer",
     "allmydata.util.pipeline",
     "allmydata.util.pollmixin",
+    "allmydata.util.rrefutil",
     "allmydata.util.spans",
     "allmydata.util.statistics",
     "allmydata.util.time_format",
diff --git a/src/allmydata/util/rrefutil.py b/src/allmydata/util/rrefutil.py
index de0f2fbd5..5d57a2f45 100644
--- a/src/allmydata/util/rrefutil.py
+++ b/src/allmydata/util/rrefutil.py
@@ -1,3 +1,14 @@
+"""
+Ported to Python 3.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 from foolscap.api import Violation, RemoteException, SturdyRef
 

From 003e9c62a8106add64564b0b2ec47df1204cd182 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 1 Apr 2021 10:58:27 -0400
Subject: [PATCH 12/19] Delete unused code paths.

---
 src/allmydata/util/dbutil.py | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/src/allmydata/util/dbutil.py b/src/allmydata/util/dbutil.py
index 543dd2797..11491a4d0 100644
--- a/src/allmydata/util/dbutil.py
+++ b/src/allmydata/util/dbutil.py
@@ -2,8 +2,6 @@
 import os, sys
 
 import sqlite3
-from sqlite3 import IntegrityError
-[IntegrityError]
 
 
 class DBError(Exception):
@@ -12,7 +10,7 @@ class DBError(Exception):
 
 def get_db(dbfile, stderr=sys.stderr,
            create_version=(None, None), updaters={}, just_create=False, dbname="db",
-           journal_mode=None, synchronous=None):
+           ):
     """Open or create the given db file. The parent directory must exist.
     create_version=(SCHEMA, VERNUM), and SCHEMA must have a 'version' table.
     Updaters is a {newver: commands} mapping, where e.g. updaters[2] is used
@@ -32,12 +30,6 @@ def get_db(dbfile, stderr=sys.stderr,
     # The default is unspecified according to <http://www.sqlite.org/foreignkeys.html#fk_enable>.
     c.execute("PRAGMA foreign_keys = ON;")
 
-    if journal_mode is not None:
-        c.execute("PRAGMA journal_mode = %s;" % (journal_mode,))
-
-    if synchronous is not None:
-        c.execute("PRAGMA synchronous = %s;" % (synchronous,))
-
     if must_create:
         c.executescript(schema)
         c.execute("INSERT INTO version (version) VALUES (?)", (target_version,))

From fd1860705ee710bcf03bd0196fd0bced9e06ef0f Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 1 Apr 2021 10:58:50 -0400
Subject: [PATCH 13/19] Port to Python 3.

---
 src/allmydata/util/_python3.py |  1 +
 src/allmydata/util/dbutil.py   | 16 ++++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/allmydata/util/_python3.py b/src/allmydata/util/_python3.py
index 56d9e6aec..d5ea3ee31 100644
--- a/src/allmydata/util/_python3.py
+++ b/src/allmydata/util/_python3.py
@@ -116,6 +116,7 @@ PORTED_MODULES = [
     "allmydata.util.configutil",
     "allmydata.util.connection_status",
     "allmydata.util.consumer",
+    "allmydata.util.dbutil",
     "allmydata.util.deferredutil",
     "allmydata.util.dictutil",
     "allmydata.util.eliotutil",
diff --git a/src/allmydata/util/dbutil.py b/src/allmydata/util/dbutil.py
index 11491a4d0..916382972 100644
--- a/src/allmydata/util/dbutil.py
+++ b/src/allmydata/util/dbutil.py
@@ -1,3 +1,19 @@
+"""
+SQLite3 utilities.
+
+Test coverage currently provided by test_backupdb.py.
+
+Ported to Python 3.
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 import os, sys
 

From 939f1f840bc99947e5c545049a27ecfdafcf1cfc Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Fri, 2 Apr 2021 12:48:50 -0400
Subject: [PATCH 14/19] Fix reference to new location.

---
 src/allmydata/introducer/server.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/allmydata/introducer/server.py b/src/allmydata/introducer/server.py
index 6d73c4026..7f72d29f6 100644
--- a/src/allmydata/introducer/server.py
+++ b/src/allmydata/introducer/server.py
@@ -226,7 +226,7 @@ class IntroducerService(service.MultiService, Referenceable):
                 # tubid will be None. Also, subscribers do not tell us which
                 # pubkey they use; only publishers do that.
                 tubid = rref.getRemoteTubID() or "?"
-                remote_address = rrefutil.stringify_remote_address(rref)
+                remote_address = stringify_remote_address(rref)
                 # these three assume subscriber_info["version"]==0, but
                 # should tolerate other versions
                 nickname = subscriber_info.get("nickname", u"?")

From dd6e0d546718a27d0ea4ff9fe03c59109113caf2 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Fri, 2 Apr 2021 12:49:01 -0400
Subject: [PATCH 15/19] Switch to decode_furl().

---
 src/allmydata/introducer/common.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/allmydata/introducer/common.py b/src/allmydata/introducer/common.py
index dd9bb527c..f6f70d861 100644
--- a/src/allmydata/introducer/common.py
+++ b/src/allmydata/introducer/common.py
@@ -12,7 +12,7 @@ if PY2:
 
 import re
 
-from foolscap.api import SturdyRef
+from foolscap.furl import decode_furl
 from allmydata.crypto.util import remove_prefix
 from allmydata.crypto import ed25519
 from allmydata.util import base32, jsonbytes as json
@@ -125,10 +125,10 @@ class AnnouncementDescriptor(object):
         self.service_name = ann_d["service-name"]
         self.version = ann_d.get("my-version", "")
         self.nickname = ann_d.get("nickname", u"")
-        (service_name, key_s) = index
+        (_, key_s) = index
         self.serverid = key_s
         furl = ann_d.get("anonymous-storage-FURL")
         if furl:
-            self.connection_hints = list(SturdyRef(furl).locationHints)
+            _, self.connection_hints, _ = decode_furl(furl)
         else:
             self.connection_hints = []

From c21288b3ddf40a338f53293bd7810813b3ad0f78 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Fri, 2 Apr 2021 12:49:58 -0400
Subject: [PATCH 16/19] Make it easier to read.

---
 src/allmydata/test/test_consumer.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/allmydata/test/test_consumer.py b/src/allmydata/test/test_consumer.py
index 46b87e477..73c99d8a3 100644
--- a/src/allmydata/test/test_consumer.py
+++ b/src/allmydata/test/test_consumer.py
@@ -28,8 +28,8 @@ class Producer(object):
     If used as streaming, the test should call iterate() manually.
     """
 
-    def __init__(self, consumer):
-        self.data = [b"abc", b"def", b"ghi"]
+    def __init__(self, consumer, data):
+        self.data = data
         self.consumer = consumer
         self.done = False
 
@@ -58,7 +58,7 @@ class MemoryConsumerTests(TestCase):
         A MemoryConsumer accumulates all data sent by a streaming producer.
         """
         consumer = MemoryConsumer()
-        producer = Producer(consumer)
+        producer = Producer(consumer, [b"abc", b"def", b"ghi"])
         consumer.registerProducer(producer, True)
         self.assertEqual(consumer.chunks, [b"abc"])
         producer.iterate()
@@ -74,7 +74,7 @@ class MemoryConsumerTests(TestCase):
         A MemoryConsumer accumulates all data sent by a non-streaming producer.
         """
         consumer = MemoryConsumer()
-        producer = Producer(consumer)
+        producer = Producer(consumer, [b"abc", b"def", b"ghi"])
         consumer.registerProducer(producer, False)
         self.assertEqual(consumer.chunks, [b"abc", b"def", b"ghi"])
         self.assertEqual(consumer.done, True)

From 9a96fec60401edaf8ab39154e7226797e92852a5 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Fri, 2 Apr 2021 12:56:49 -0400
Subject: [PATCH 17/19] Use existing IRemoteReference implementation.

---
 src/allmydata/test/test_util.py | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/src/allmydata/test/test_util.py b/src/allmydata/test/test_util.py
index 7b0b52783..2f77edf4d 100644
--- a/src/allmydata/test/test_util.py
+++ b/src/allmydata/test/test_util.py
@@ -28,7 +28,7 @@ from allmydata.util import yamlutil
 from allmydata.util import rrefutil
 from allmydata.util.fileutil import EncryptedTemporaryFile
 from allmydata.test.common_util import ReallyEqualMixin
-
+from .no_network import fireNow, LocalWrapper
 
 if six.PY3:
     long = int
@@ -531,17 +531,16 @@ class JSONBytes(unittest.TestCase):
         self.assertEqual(json.loads(encoded, encoding="utf-8"), x)
 
 
-class FakeRemoteRef(object):
-    """Emulate a RemoteRef."""
+class FakeGetVersion(object):
+    """Emulate an object with a get_version."""
 
     def __init__(self, result):
         self.result = result
 
-    def callRemote(self, method):
-        assert method == "get_version"
+    def remote_get_version(self):
         if isinstance(self.result, Exception):
-            return defer.fail(self.result)
-        return defer.succeed(self.result)
+            raise self.result
+        return self.result
 
 
 class RrefUtilTests(unittest.TestCase):
@@ -549,7 +548,7 @@ class RrefUtilTests(unittest.TestCase):
 
     def test_version_returned(self):
         """If get_version() succeeded, it is set on the rref."""
-        rref = FakeRemoteRef(12345)
+        rref = LocalWrapper(FakeGetVersion(12345), fireNow)
         result = self.successResultOf(
             rrefutil.add_version_to_remote_reference(rref, "default")
         )
@@ -559,7 +558,7 @@ class RrefUtilTests(unittest.TestCase):
     def test_exceptions(self):
         """If get_version() failed, default version is set on the rref."""
         for exception in (Violation(), RemoteException(ValueError())):
-            rref = FakeRemoteRef(exception)
+            rref = LocalWrapper(FakeGetVersion(exception), fireNow)
             result = self.successResultOf(
                 rrefutil.add_version_to_remote_reference(rref, "Default")
             )

From d214fe3f16a8eeaf7fbd003ef2a1cdfe54692b88 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Fri, 2 Apr 2021 13:00:05 -0400
Subject: [PATCH 18/19] Delete unused imports.

---
 src/allmydata/introducer/server.py  | 2 +-
 src/allmydata/test/test_consumer.py | 2 +-
 src/allmydata/test/test_util.py     | 1 -
 src/allmydata/util/rrefutil.py      | 2 +-
 4 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/allmydata/introducer/server.py b/src/allmydata/introducer/server.py
index 7f72d29f6..1e28f511b 100644
--- a/src/allmydata/introducer/server.py
+++ b/src/allmydata/introducer/server.py
@@ -29,7 +29,7 @@ from twisted.python.failure import Failure
 from foolscap.api import Referenceable
 import allmydata
 from allmydata import node
-from allmydata.util import log, rrefutil, dictutil
+from allmydata.util import log, dictutil
 from allmydata.util.i2p_provider import create as create_i2p_provider
 from allmydata.util.tor_provider import create as create_tor_provider
 from allmydata.introducer.interfaces import \
diff --git a/src/allmydata/test/test_consumer.py b/src/allmydata/test/test_consumer.py
index 73c99d8a3..a689de462 100644
--- a/src/allmydata/test/test_consumer.py
+++ b/src/allmydata/test/test_consumer.py
@@ -17,7 +17,7 @@ from zope.interface import implementer
 from twisted.trial.unittest import TestCase
 from twisted.internet.interfaces import IPushProducer, IPullProducer
 
-from allmydata.util.consumer import MemoryConsumer, download_to_data
+from allmydata.util.consumer import MemoryConsumer
 
 
 @implementer(IPushProducer)
diff --git a/src/allmydata/test/test_util.py b/src/allmydata/test/test_util.py
index 2f77edf4d..9887897cf 100644
--- a/src/allmydata/test/test_util.py
+++ b/src/allmydata/test/test_util.py
@@ -17,7 +17,6 @@ import yaml
 import json
 
 from twisted.trial import unittest
-from twisted.internet import defer
 from foolscap.api import Violation, RemoteException
 
 from allmydata.util import idlib, mathutil
diff --git a/src/allmydata/util/rrefutil.py b/src/allmydata/util/rrefutil.py
index 5d57a2f45..f39890ff1 100644
--- a/src/allmydata/util/rrefutil.py
+++ b/src/allmydata/util/rrefutil.py
@@ -10,7 +10,7 @@ from future.utils import PY2
 if PY2:
     from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
-from foolscap.api import Violation, RemoteException, SturdyRef
+from foolscap.api import Violation, RemoteException
 
 
 def add_version_to_remote_reference(rref, default):

From e074034e8f88db453bc0dc46e149b65e143664b9 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Mon, 5 Apr 2021 10:24:04 -0400
Subject: [PATCH 19/19] News file.

---
 newsfragments/3657.minor | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 newsfragments/3657.minor

diff --git a/newsfragments/3657.minor b/newsfragments/3657.minor
new file mode 100644
index 000000000..e69de29bb