From 113eeb0e5908887aac8b03bd59a23fdc6999a3c5 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 4 May 2022 10:21:55 -0400
Subject: [PATCH 01/13] News file.

---
 newsfragments/3891.minor | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 newsfragments/3891.minor

diff --git a/newsfragments/3891.minor b/newsfragments/3891.minor
new file mode 100644
index 000000000..e69de29bb

From c1ce74f88d346d92299af11c11ab01789d368c4e Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 4 May 2022 11:03:14 -0400
Subject: [PATCH 02/13] Ability to list shares, enabling more of IStorageClient
 to run over HTTP.

---
 docs/proposed/http-storage-node-protocol.rst |  2 +-
 src/allmydata/storage/http_client.py         | 20 ++++++++++++
 src/allmydata/storage/http_server.py         | 14 ++++++++
 src/allmydata/storage/server.py              | 34 +++++++++++++-------
 src/allmydata/storage_client.py              |  5 +--
 src/allmydata/test/test_istorageserver.py    |  1 -
 6 files changed, 60 insertions(+), 16 deletions(-)

diff --git a/docs/proposed/http-storage-node-protocol.rst b/docs/proposed/http-storage-node-protocol.rst
index 3926d9f4a..693ce9290 100644
--- a/docs/proposed/http-storage-node-protocol.rst
+++ b/docs/proposed/http-storage-node-protocol.rst
@@ -738,7 +738,7 @@ Reading
 ``GET /v1/mutable/:storage_index/shares``
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
-Retrieve a list indicating all shares available for the indicated storage index.
+Retrieve a set indicating all shares available for the indicated storage index.
 For example::
 
   [1, 5]
diff --git a/src/allmydata/storage/http_client.py b/src/allmydata/storage/http_client.py
index da350e0c6..5920d5a5b 100644
--- a/src/allmydata/storage/http_client.py
+++ b/src/allmydata/storage/http_client.py
@@ -106,6 +106,11 @@ _SCHEMAS = {
         share_number = uint
         """
     ),
+    "mutable_list_shares": Schema(
+        """
+        response = #6.258([* uint])
+        """
+    ),
 }
 
 
@@ -720,3 +725,18 @@ class StorageClientMutables:
         return read_share_chunk(
             self._client, "mutable", storage_index, share_number, offset, length
         )
+
+    @async_to_deferred
+    async def list_shares(self, storage_index: bytes) -> set[int]:
+        """
+        List the share numbers for a given storage index.
+        """
+        # TODO unit test all the things
+        url = self._client.relative_url(
+            "/v1/mutable/{}/shares".format(_encode_si(storage_index))
+        )
+        response = await self._client.request("GET", url)
+        if response.code == http.OK:
+            return await _decode_cbor(response, _SCHEMAS["mutable_list_shares"])
+        else:
+            raise ClientException(response.code)
diff --git a/src/allmydata/storage/http_server.py b/src/allmydata/storage/http_server.py
index 0169d1463..0b407a1c4 100644
--- a/src/allmydata/storage/http_server.py
+++ b/src/allmydata/storage/http_server.py
@@ -645,6 +645,20 @@ class HTTPServer(object):
             )
         return data
 
+    @_authorized_route(
+        _app,
+        set(),
+        "/v1/mutable/<storage_index:storage_index>/shares",
+        methods=["GET"],
+    )
+    def list_mutable_shares(self, request, authorization, storage_index):
+        """List mutable shares for a storage index."""
+        try:
+            shares = self._storage_server.list_mutable_shares(storage_index)
+        except KeyError:
+            raise _HTTPError(http.NOT_FOUND)
+        return self._send_encoded(request, shares)
+
 
 @implementer(IStreamServerEndpoint)
 @attr.s
diff --git a/src/allmydata/storage/server.py b/src/allmydata/storage/server.py
index 9d1a3d6a4..1a0255601 100644
--- a/src/allmydata/storage/server.py
+++ b/src/allmydata/storage/server.py
@@ -1,18 +1,9 @@
 """
 Ported to Python 3.
 """
-from __future__ import division
-from __future__ import absolute_import
-from __future__ import print_function
-from __future__ import unicode_literals
-
-from future.utils import bytes_to_native_str, PY2
-if PY2:
-    # Omit open() to get native behavior where open("w") always accepts native
-    # strings. Omit bytes so we don't leak future's custom bytes.
-    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, pow, round, super, dict, list, object, range, str, max, min  # noqa: F401
-else:
-    from typing import Dict, Tuple
+from __future__ import annotations
+from future.utils import bytes_to_native_str
+from typing import Dict, Tuple
 
 import os, re
 
@@ -699,6 +690,25 @@ class StorageServer(service.MultiService):
                                          self)
         return share
 
+    def list_mutable_shares(self, storage_index) -> set[int]:
+        """List all share numbers for the given mutable.
+
+        Raises ``KeyError`` if the storage index is not known.
+        """
+        # TODO unit test
+        si_dir = storage_index_to_dir(storage_index)
+        # shares exist if there is a file for them
+        bucketdir = os.path.join(self.sharedir, si_dir)
+        if not os.path.isdir(bucketdir):
+            raise KeyError("Not found")
+        result = set()
+        for sharenum_s in os.listdir(bucketdir):
+            try:
+                result.add(int(sharenum_s))
+            except ValueError:
+                continue
+        return result
+
     def slot_readv(self, storage_index, shares, readv):
         start = self._clock.seconds()
         self.count("readv")
diff --git a/src/allmydata/storage_client.py b/src/allmydata/storage_client.py
index 68164e697..8b2f68a9e 100644
--- a/src/allmydata/storage_client.py
+++ b/src/allmydata/storage_client.py
@@ -1196,9 +1196,10 @@ class _HTTPStorageServer(object):
         mutable_client = StorageClientMutables(self._http_client)
         pending_reads = {}
         reads = {}
-        # TODO if shares list is empty, that means list all shares, so we need
+        # If shares list is empty, that means list all shares, so we need
         # to do a query to get that.
-        assert shares  # TODO replace with call to list shares if and only if it's empty
+        if not shares:
+            shares = yield mutable_client.list_shares(storage_index)
 
         # Start all the queries in parallel:
         for share_number in shares:
diff --git a/src/allmydata/test/test_istorageserver.py b/src/allmydata/test/test_istorageserver.py
index e7b869713..d9fd13acb 100644
--- a/src/allmydata/test/test_istorageserver.py
+++ b/src/allmydata/test/test_istorageserver.py
@@ -1154,5 +1154,4 @@ class HTTPMutableAPIsTests(
         "test_add_lease_renewal",
         "test_add_new_lease",
         "test_advise_corrupt_share",
-        "test_slot_readv_no_shares",
     }

From 852162ba0694f0405666d432d39b464f646eeca0 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 4 May 2022 11:03:35 -0400
Subject: [PATCH 03/13] More accurate docs.

---
 src/allmydata/storage/http_client.py | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/allmydata/storage/http_client.py b/src/allmydata/storage/http_client.py
index 5920d5a5b..2db28dc72 100644
--- a/src/allmydata/storage/http_client.py
+++ b/src/allmydata/storage/http_client.py
@@ -380,16 +380,14 @@ def read_share_chunk(
     """
     Download a chunk of data from a share.
 
-    TODO https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3857 Failed
-    downloads should be transparently retried and redownloaded by the
-    implementation a few times so that if a failure percolates up, the
-    caller can assume the failure isn't a short-term blip.
+    TODO https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3857 Failed downloads
+    should be transparently retried and redownloaded by the implementation a
+    few times so that if a failure percolates up, the caller can assume the
+    failure isn't a short-term blip.
 
-    NOTE: the underlying HTTP protocol is much more flexible than this API,
-    so a future refactor may expand this in order to simplify the calling
-    code and perhaps download data more efficiently.  But then again maybe
-    the HTTP protocol will be simplified, see
-    https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3777
+    NOTE: the underlying HTTP protocol is somewhat more flexible than this API,
+    insofar as it doesn't always require a range.  In practice a range is
+    always provided by the current callers.
     """
     url = client.relative_url(
         "/v1/{}/{}/{}".format(share_type, _encode_si(storage_index), share_number)
@@ -717,7 +715,7 @@ class StorageClientMutables:
         share_number: int,
         offset: int,
         length: int,
-    ) -> bytes:
+    ) -> Deferred[bytes]:
         """
         Download a chunk of data from a share.
         """

From 06029d2878b6ad6edc67ae79dc1f59124c6934f0 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 4 May 2022 11:25:13 -0400
Subject: [PATCH 04/13] Another end-to-end test passing (albeit with ugly
 implementation).

---
 src/allmydata/storage/http_client.py      |  6 +++++
 src/allmydata/storage/http_server.py      | 33 ++++++++++++++---------
 src/allmydata/test/test_istorageserver.py |  1 -
 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/src/allmydata/storage/http_client.py b/src/allmydata/storage/http_client.py
index 2db28dc72..0229bef03 100644
--- a/src/allmydata/storage/http_client.py
+++ b/src/allmydata/storage/http_client.py
@@ -706,6 +706,12 @@ class StorageClientMutables:
         if response.code == http.OK:
             result = await _decode_cbor(response, _SCHEMAS["mutable_read_test_write"])
             return ReadTestWriteResult(success=result["success"], reads=result["data"])
+        elif response.code == http.UNAUTHORIZED:
+            # TODO mabye we can fix this to be nicer at some point? Custom
+            # exception?
+            from foolscap.api import RemoteException
+
+            raise RemoteException("Authorization failed")
         else:
             raise ClientException(response.code, (await response.content()))
 
diff --git a/src/allmydata/storage/http_server.py b/src/allmydata/storage/http_server.py
index 0b407a1c4..748790a72 100644
--- a/src/allmydata/storage/http_server.py
+++ b/src/allmydata/storage/http_server.py
@@ -46,6 +46,7 @@ from .common import si_a2b
 from .immutable import BucketWriter, ConflictingWriteError
 from ..util.hashutil import timing_safe_compare
 from ..util.base32 import rfc3548_alphabet
+from allmydata.interfaces import BadWriteEnablerError
 
 
 class ClientSecretsException(Exception):
@@ -587,19 +588,25 @@ class HTTPServer(object):
             authorization[Secrets.LEASE_RENEW],
             authorization[Secrets.LEASE_CANCEL],
         )
-        success, read_data = self._storage_server.slot_testv_and_readv_and_writev(
-            storage_index,
-            secrets,
-            {
-                k: (
-                    [(d["offset"], d["size"], b"eq", d["specimen"]) for d in v["test"]],
-                    [(d["offset"], d["data"]) for d in v["write"]],
-                    v["new-length"],
-                )
-                for (k, v) in rtw_request["test-write-vectors"].items()
-            },
-            [(d["offset"], d["size"]) for d in rtw_request["read-vector"]],
-        )
+        try:
+            success, read_data = self._storage_server.slot_testv_and_readv_and_writev(
+                storage_index,
+                secrets,
+                {
+                    k: (
+                        [
+                            (d["offset"], d["size"], b"eq", d["specimen"])
+                            for d in v["test"]
+                        ],
+                        [(d["offset"], d["data"]) for d in v["write"]],
+                        v["new-length"],
+                    )
+                    for (k, v) in rtw_request["test-write-vectors"].items()
+                },
+                [(d["offset"], d["size"]) for d in rtw_request["read-vector"]],
+            )
+        except BadWriteEnablerError:
+            raise _HTTPError(http.UNAUTHORIZED)
         return self._send_encoded(request, {"success": success, "data": read_data})
 
     @_authorized_route(
diff --git a/src/allmydata/test/test_istorageserver.py b/src/allmydata/test/test_istorageserver.py
index d9fd13acb..a3e75bbac 100644
--- a/src/allmydata/test/test_istorageserver.py
+++ b/src/allmydata/test/test_istorageserver.py
@@ -1150,7 +1150,6 @@ class HTTPMutableAPIsTests(
 
     # TODO will be implemented in later tickets
     SKIP_TESTS = {
-        "test_STARAW_write_enabler_must_match",
         "test_add_lease_renewal",
         "test_add_new_lease",
         "test_advise_corrupt_share",

From 2833bec80e7e6ff069b4b6eee890f99942c3dfc4 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 5 May 2022 12:04:45 -0400
Subject: [PATCH 05/13] Unit test the new storage server backend API.

---
 src/allmydata/storage/server.py    |  1 -
 src/allmydata/test/test_storage.py | 25 +++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/allmydata/storage/server.py b/src/allmydata/storage/server.py
index 1a0255601..b46303cd8 100644
--- a/src/allmydata/storage/server.py
+++ b/src/allmydata/storage/server.py
@@ -695,7 +695,6 @@ class StorageServer(service.MultiService):
 
         Raises ``KeyError`` if the storage index is not known.
         """
-        # TODO unit test
         si_dir = storage_index_to_dir(storage_index)
         # shares exist if there is a file for them
         bucketdir = os.path.join(self.sharedir, si_dir)
diff --git a/src/allmydata/test/test_storage.py b/src/allmydata/test/test_storage.py
index b37f74c24..8f1ece401 100644
--- a/src/allmydata/test/test_storage.py
+++ b/src/allmydata/test/test_storage.py
@@ -1315,6 +1315,31 @@ class MutableServer(unittest.TestCase):
         self.failUnless(isinstance(readv_data, dict))
         self.failUnlessEqual(len(readv_data), 0)
 
+    def test_list_mutable_shares(self):
+        """
+        ``StorageServer.list_mutable_shares()`` returns a set of share numbers
+        for the given storage index, or raises ``KeyError`` if it does not exist at all.
+        """
+        ss = self.create("test_list_mutable_shares")
+
+        # Initially, nothing exists:
+        with self.assertRaises(KeyError):
+            ss.list_mutable_shares(b"si1")
+
+        self.allocate(ss, b"si1", b"we1", b"le1", [0, 1, 4, 2], 12)
+        shares0_1_2_4 = ss.list_mutable_shares(b"si1")
+
+        # Remove share 2, by setting size to 0:
+        secrets = (self.write_enabler(b"we1"),
+                   self.renew_secret(b"le1"),
+                   self.cancel_secret(b"le1"))
+        ss.slot_testv_and_readv_and_writev(b"si1", secrets, {2: ([], [], 0)}, [])
+        shares0_1_4 = ss.list_mutable_shares(b"si1")
+        self.assertEqual(
+            (shares0_1_2_4, shares0_1_4),
+            ({0, 1, 2, 4}, {0, 1, 4})
+        )
+
     def test_bad_magic(self):
         ss = self.create("test_bad_magic")
         self.allocate(ss, b"si1", b"we1", next(self._lease_secret), set([0]), 10)

From b3fed56c00d03599b4a8479e5de0a36c696c7a97 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Thu, 5 May 2022 12:11:09 -0400
Subject: [PATCH 06/13] Move Foolscap compatibility to a better place.

---
 src/allmydata/storage/http_client.py |  6 ------
 src/allmydata/storage_client.py      | 16 +++++++++++-----
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/allmydata/storage/http_client.py b/src/allmydata/storage/http_client.py
index 0229bef03..2db28dc72 100644
--- a/src/allmydata/storage/http_client.py
+++ b/src/allmydata/storage/http_client.py
@@ -706,12 +706,6 @@ class StorageClientMutables:
         if response.code == http.OK:
             result = await _decode_cbor(response, _SCHEMAS["mutable_read_test_write"])
             return ReadTestWriteResult(success=result["success"], reads=result["data"])
-        elif response.code == http.UNAUTHORIZED:
-            # TODO mabye we can fix this to be nicer at some point? Custom
-            # exception?
-            from foolscap.api import RemoteException
-
-            raise RemoteException("Authorization failed")
         else:
             raise ClientException(response.code, (await response.content()))
 
diff --git a/src/allmydata/storage_client.py b/src/allmydata/storage_client.py
index 8b2f68a9e..cd489a307 100644
--- a/src/allmydata/storage_client.py
+++ b/src/allmydata/storage_client.py
@@ -50,6 +50,7 @@ from zope.interface import (
     Interface,
     implementer,
 )
+from twisted.web import http
 from twisted.internet import defer
 from twisted.application import service
 from twisted.plugin import (
@@ -78,7 +79,7 @@ from allmydata.util.dictutil import BytesKeyDict, UnicodeKeyDict
 from allmydata.storage.http_client import (
     StorageClient, StorageClientImmutables, StorageClientGeneral,
     ClientException as HTTPClientException, StorageClientMutables,
-    ReadVector, TestWriteVectors, WriteVector, TestVector
+    ReadVector, TestWriteVectors, WriteVector, TestVector, ClientException
 )
 
 
@@ -1247,8 +1248,13 @@ class _HTTPStorageServer(object):
             ReadVector(offset=offset, size=size)
             for (offset, size) in r_vector
         ]
-        client_result = yield mutable_client.read_test_write_chunks(
-            storage_index, we_secret, lr_secret, lc_secret, client_tw_vectors,
-            client_read_vectors,
-        )
+        try:
+            client_result = yield mutable_client.read_test_write_chunks(
+                storage_index, we_secret, lr_secret, lc_secret, client_tw_vectors,
+                client_read_vectors,
+            )
+        except ClientException as e:
+            if e.code == http.UNAUTHORIZED:
+                raise RemoteException("Unauthorized write, possibly you passed the wrong write enabler?")
+            raise
         return (client_result.success, client_result.reads)

From 5b0762d3a3a8fa1eb98aa6cd3b5b4d14e53047a3 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Tue, 10 May 2022 13:59:58 -0400
Subject: [PATCH 07/13] Workaround for autobahn issues.

---
 setup.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/setup.py b/setup.py
index c84d0ecde..2b4fd6988 100644
--- a/setup.py
+++ b/setup.py
@@ -114,7 +114,7 @@ install_requires = [
     "attrs >= 18.2.0",
 
     # WebSocket library for twisted and asyncio
-    "autobahn >= 19.5.2",
+    "autobahn < 22.4.1",  # remove this when https://github.com/crossbario/autobahn-python/issues/1566 is fixed
 
     # Support for Python 3 transition
     "future >= 0.18.2",

From 4afe3eb224d6f26ac768aaccbca68c69035d57d4 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 11 May 2022 10:58:13 -0400
Subject: [PATCH 08/13] Clarify sets vs lists some more.

---
 docs/proposed/http-storage-node-protocol.rst | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/docs/proposed/http-storage-node-protocol.rst b/docs/proposed/http-storage-node-protocol.rst
index 693ce9290..7e0b4a542 100644
--- a/docs/proposed/http-storage-node-protocol.rst
+++ b/docs/proposed/http-storage-node-protocol.rst
@@ -350,8 +350,10 @@ Because of the simple types used throughout
 and the equivalence described in `RFC 7049`_
 these examples should be representative regardless of which of these two encodings is chosen.
 
+The one exception is sets.
 For CBOR messages, any sequence that is semantically a set (i.e. no repeated values allowed, order doesn't matter, and elements are hashable in Python) should be sent as a set.
 Tag 6.258 is used to indicate sets in CBOR; see `the CBOR registry <https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml>`_ for more details.
+Sets will be represented as JSON lists in examples because JSON doesn't support sets.
 
 HTTP Design
 ~~~~~~~~~~~
@@ -739,7 +741,7 @@ Reading
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
 Retrieve a set indicating all shares available for the indicated storage index.
-For example::
+For example (this is shown as list, since it will be list for JSON, but will be set for CBOR)::
 
   [1, 5]
 

From 07e16b80b5df22a5620d390cb34032a55e62e795 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 11 May 2022 11:00:05 -0400
Subject: [PATCH 09/13] Better name.

---
 src/allmydata/storage/http_server.py |  4 ++--
 src/allmydata/storage/server.py      |  2 +-
 src/allmydata/test/test_storage.py   | 12 ++++++------
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/allmydata/storage/http_server.py b/src/allmydata/storage/http_server.py
index 748790a72..96e906e43 100644
--- a/src/allmydata/storage/http_server.py
+++ b/src/allmydata/storage/http_server.py
@@ -658,10 +658,10 @@ class HTTPServer(object):
         "/v1/mutable/<storage_index:storage_index>/shares",
         methods=["GET"],
     )
-    def list_mutable_shares(self, request, authorization, storage_index):
+    def enumerate_mutable_shares(self, request, authorization, storage_index):
         """List mutable shares for a storage index."""
         try:
-            shares = self._storage_server.list_mutable_shares(storage_index)
+            shares = self._storage_server.enumerate_mutable_shares(storage_index)
         except KeyError:
             raise _HTTPError(http.NOT_FOUND)
         return self._send_encoded(request, shares)
diff --git a/src/allmydata/storage/server.py b/src/allmydata/storage/server.py
index b46303cd8..ab7947bf9 100644
--- a/src/allmydata/storage/server.py
+++ b/src/allmydata/storage/server.py
@@ -690,7 +690,7 @@ class StorageServer(service.MultiService):
                                          self)
         return share
 
-    def list_mutable_shares(self, storage_index) -> set[int]:
+    def enumerate_mutable_shares(self, storage_index) -> set[int]:
         """List all share numbers for the given mutable.
 
         Raises ``KeyError`` if the storage index is not known.
diff --git a/src/allmydata/test/test_storage.py b/src/allmydata/test/test_storage.py
index 8f1ece401..9bc218fa6 100644
--- a/src/allmydata/test/test_storage.py
+++ b/src/allmydata/test/test_storage.py
@@ -1315,26 +1315,26 @@ class MutableServer(unittest.TestCase):
         self.failUnless(isinstance(readv_data, dict))
         self.failUnlessEqual(len(readv_data), 0)
 
-    def test_list_mutable_shares(self):
+    def test_enumerate_mutable_shares(self):
         """
-        ``StorageServer.list_mutable_shares()`` returns a set of share numbers
+        ``StorageServer.enumerate_mutable_shares()`` returns a set of share numbers
         for the given storage index, or raises ``KeyError`` if it does not exist at all.
         """
-        ss = self.create("test_list_mutable_shares")
+        ss = self.create("test_enumerate_mutable_shares")
 
         # Initially, nothing exists:
         with self.assertRaises(KeyError):
-            ss.list_mutable_shares(b"si1")
+            ss.enumerate_mutable_shares(b"si1")
 
         self.allocate(ss, b"si1", b"we1", b"le1", [0, 1, 4, 2], 12)
-        shares0_1_2_4 = ss.list_mutable_shares(b"si1")
+        shares0_1_2_4 = ss.enumerate_mutable_shares(b"si1")
 
         # Remove share 2, by setting size to 0:
         secrets = (self.write_enabler(b"we1"),
                    self.renew_secret(b"le1"),
                    self.cancel_secret(b"le1"))
         ss.slot_testv_and_readv_and_writev(b"si1", secrets, {2: ([], [], 0)}, [])
-        shares0_1_4 = ss.list_mutable_shares(b"si1")
+        shares0_1_4 = ss.enumerate_mutable_shares(b"si1")
         self.assertEqual(
             (shares0_1_2_4, shares0_1_4),
             ({0, 1, 2, 4}, {0, 1, 4})

From 6d412a017c34fc6f6528c89b1443d9bdf7caee64 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 11 May 2022 11:00:46 -0400
Subject: [PATCH 10/13] Type annotation.

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

diff --git a/src/allmydata/storage/server.py b/src/allmydata/storage/server.py
index ab7947bf9..f1b835780 100644
--- a/src/allmydata/storage/server.py
+++ b/src/allmydata/storage/server.py
@@ -690,7 +690,7 @@ class StorageServer(service.MultiService):
                                          self)
         return share
 
-    def enumerate_mutable_shares(self, storage_index) -> set[int]:
+    def enumerate_mutable_shares(self, storage_index: bytes) -> set[int]:
         """List all share numbers for the given mutable.
 
         Raises ``KeyError`` if the storage index is not known.

From 4b62ec082bed7ecc33612741dfbffc16868ca3ff Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 11 May 2022 11:11:24 -0400
Subject: [PATCH 11/13] Match Foolscap behavior for slot_readv of unknown
 storage index.

---
 src/allmydata/storage_client.py           |  8 +++++++-
 src/allmydata/test/test_istorageserver.py | 16 ++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/allmydata/storage_client.py b/src/allmydata/storage_client.py
index cd489a307..83a1233f5 100644
--- a/src/allmydata/storage_client.py
+++ b/src/allmydata/storage_client.py
@@ -1200,7 +1200,13 @@ class _HTTPStorageServer(object):
         # If shares list is empty, that means list all shares, so we need
         # to do a query to get that.
         if not shares:
-            shares = yield mutable_client.list_shares(storage_index)
+            try:
+                shares = yield mutable_client.list_shares(storage_index)
+            except ClientException as e:
+                if e.code == http.NOT_FOUND:
+                    shares = set()
+                else:
+                    raise
 
         # Start all the queries in parallel:
         for share_number in shares:
diff --git a/src/allmydata/test/test_istorageserver.py b/src/allmydata/test/test_istorageserver.py
index a3e75bbac..66535ddda 100644
--- a/src/allmydata/test/test_istorageserver.py
+++ b/src/allmydata/test/test_istorageserver.py
@@ -854,6 +854,22 @@ class IStorageServerMutableAPIsTestsMixin(object):
             {0: [b"abcdefg"], 1: [b"0123456"], 2: [b"9876543"]},
         )
 
+    @inlineCallbacks
+    def test_slot_readv_unknown_storage_index(self):
+        """
+        With unknown storage index, ``IStorageServer.slot_readv()`` TODO.
+        """
+        storage_index = new_storage_index()
+        reads = yield self.storage_client.slot_readv(
+            storage_index,
+            shares=[],
+            readv=[(0, 7)],
+        )
+        self.assertEqual(
+            reads,
+            {},
+        )
+
     @inlineCallbacks
     def create_slot(self):
         """Create a slot with sharenum 0."""

From 457db8f992c62e8f5c5bc4cdcb6e99f097062f08 Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Wed, 11 May 2022 11:17:57 -0400
Subject: [PATCH 12/13] Get rid of the "no such storage index" edge case, since
 it's not really necessary.

---
 src/allmydata/storage/http_server.py |  5 +----
 src/allmydata/storage/server.py      |  7 ++-----
 src/allmydata/storage_client.py      |  8 +-------
 src/allmydata/test/test_storage.py   | 12 ++++++------
 4 files changed, 10 insertions(+), 22 deletions(-)

diff --git a/src/allmydata/storage/http_server.py b/src/allmydata/storage/http_server.py
index 96e906e43..a1641f563 100644
--- a/src/allmydata/storage/http_server.py
+++ b/src/allmydata/storage/http_server.py
@@ -660,10 +660,7 @@ class HTTPServer(object):
     )
     def enumerate_mutable_shares(self, request, authorization, storage_index):
         """List mutable shares for a storage index."""
-        try:
-            shares = self._storage_server.enumerate_mutable_shares(storage_index)
-        except KeyError:
-            raise _HTTPError(http.NOT_FOUND)
+        shares = self._storage_server.enumerate_mutable_shares(storage_index)
         return self._send_encoded(request, shares)
 
 
diff --git a/src/allmydata/storage/server.py b/src/allmydata/storage/server.py
index f1b835780..bcf44dc30 100644
--- a/src/allmydata/storage/server.py
+++ b/src/allmydata/storage/server.py
@@ -691,15 +691,12 @@ class StorageServer(service.MultiService):
         return share
 
     def enumerate_mutable_shares(self, storage_index: bytes) -> set[int]:
-        """List all share numbers for the given mutable.
-
-        Raises ``KeyError`` if the storage index is not known.
-        """
+        """Return all share numbers for the given mutable."""
         si_dir = storage_index_to_dir(storage_index)
         # shares exist if there is a file for them
         bucketdir = os.path.join(self.sharedir, si_dir)
         if not os.path.isdir(bucketdir):
-            raise KeyError("Not found")
+            return set()
         result = set()
         for sharenum_s in os.listdir(bucketdir):
             try:
diff --git a/src/allmydata/storage_client.py b/src/allmydata/storage_client.py
index 83a1233f5..cd489a307 100644
--- a/src/allmydata/storage_client.py
+++ b/src/allmydata/storage_client.py
@@ -1200,13 +1200,7 @@ class _HTTPStorageServer(object):
         # If shares list is empty, that means list all shares, so we need
         # to do a query to get that.
         if not shares:
-            try:
-                shares = yield mutable_client.list_shares(storage_index)
-            except ClientException as e:
-                if e.code == http.NOT_FOUND:
-                    shares = set()
-                else:
-                    raise
+            shares = yield mutable_client.list_shares(storage_index)
 
         # Start all the queries in parallel:
         for share_number in shares:
diff --git a/src/allmydata/test/test_storage.py b/src/allmydata/test/test_storage.py
index 9bc218fa6..65d09de25 100644
--- a/src/allmydata/test/test_storage.py
+++ b/src/allmydata/test/test_storage.py
@@ -1317,14 +1317,14 @@ class MutableServer(unittest.TestCase):
 
     def test_enumerate_mutable_shares(self):
         """
-        ``StorageServer.enumerate_mutable_shares()`` returns a set of share numbers
-        for the given storage index, or raises ``KeyError`` if it does not exist at all.
+        ``StorageServer.enumerate_mutable_shares()`` returns a set of share
+        numbers for the given storage index, or an empty set if it does not
+        exist at all.
         """
         ss = self.create("test_enumerate_mutable_shares")
 
         # Initially, nothing exists:
-        with self.assertRaises(KeyError):
-            ss.enumerate_mutable_shares(b"si1")
+        empty = ss.enumerate_mutable_shares(b"si1")
 
         self.allocate(ss, b"si1", b"we1", b"le1", [0, 1, 4, 2], 12)
         shares0_1_2_4 = ss.enumerate_mutable_shares(b"si1")
@@ -1336,8 +1336,8 @@ class MutableServer(unittest.TestCase):
         ss.slot_testv_and_readv_and_writev(b"si1", secrets, {2: ([], [], 0)}, [])
         shares0_1_4 = ss.enumerate_mutable_shares(b"si1")
         self.assertEqual(
-            (shares0_1_2_4, shares0_1_4),
-            ({0, 1, 2, 4}, {0, 1, 4})
+            (empty, shares0_1_2_4, shares0_1_4),
+            (set(), {0, 1, 2, 4}, {0, 1, 4})
         )
 
     def test_bad_magic(self):

From da4deab167187ec4baf02f84da8e8ae7e03a6a8a Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Mon, 16 May 2022 11:19:46 -0400
Subject: [PATCH 13/13] Note version with fix.

---
 setup.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/setup.py b/setup.py
index 2b4fd6988..d07031cd9 100644
--- a/setup.py
+++ b/setup.py
@@ -114,7 +114,7 @@ install_requires = [
     "attrs >= 18.2.0",
 
     # WebSocket library for twisted and asyncio
-    "autobahn < 22.4.1",  # remove this when https://github.com/crossbario/autobahn-python/issues/1566 is fixed
+    "autobahn < 22.4.1",  # remove this when 22.4.3 is released
 
     # Support for Python 3 transition
     "future >= 0.18.2",