Town: Iceshrimp.NET joins, and its mentions go nowhere new

Iceshrimp.NET 2026.1.2-beta runs in the pasture with AuthorizedFetch on;
its driver registers through the native API and takes Mastodon tokens from
its OAuth form. The pair passes 225 cells. A new Iceshrimp note reaches its
author's followers only, never an account it mentions or answers, until it
is edited (G-0004, peer): delivery cells now say when a server holds a post
only because it was addressed.

The checker credits a seeder's fetch to the object fetched, not to the reply
that needed it; the seeder skips the wait for an accept whose follow was
already accepted; the PrivaPub driver signs its roots in again when a run
reuses saved sessions.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

tools/pasture/town/dialects/iceshrimp.py

@@ -0,0 +1,91 @@
+"""Iceshrimp.NET 2026.1: accounts through its own API (/api/iceshrimp/auth/register, registrations open in the pasture),
+Mastodon API tokens through its OAuth page, which takes the user's name and password itself (an ASP.NET form with an
+antiforgery token). Its database keeps Misskey's shape (`note`, `poll`), with likes counted apart from reactions."""
+import html
+import re
+import urllib.parse
+
+from core import podman
+from dialects.base import Stored
+from dialects.mastodon_api import MastodonApi
+
+OOB = "urn:ietf:wg:oauth:2.0:oob"
+VIS = {"public": "public", "home": "unlisted", "followers": "followers", "specified": "direct"}
+
+
+class Iceshrimp(MastodonApi):
+	platform = "iceshrimp"
+	caps = MastodonApi.caps | {"quote", "react"}
+
+	def provision(self, accounts):
+		app = self.http.post(self.base + "/api/v1/apps", ok={200}, form={
+			"client_name": "pasture-town", "redirect_uris": OOB, "scopes": "read write follow"}).json()
+		sessions = []
+		existing = {r["username"] for r in podman.psql("iceshrimp", 'select username from "user" where host is null')}
+		for a in accounts:
+			# its login answers an unknown name by cutting the connection short, so only new names are registered
+			if a.username not in existing:
+				self.http.post(self.base + "/api/iceshrimp/auth/register", ok={200},
+							   json={"username": a.username, "password": a.password})
+			sessions.append(self.session_from_token(a, self._token(app, a)))
+		return sessions
+
+	def _token(self, app, a):
+		cookies = {}
+
+		def send(method, path, form=None):
+			headers = {"Accept": "text/html,*/*"}
+			if cookies:
+				headers["Cookie"] = "; ".join(f"{k}={v}" for k, v in cookies.items())
+			r = self.http.request(method, self.base + path, headers=headers, form=form)
+			for k, v in r.headers:
+				if k.lower() == "set-cookie":
+					name, _, value = v.split(";")[0].partition("=")
+					cookies[name.strip()] = value.strip()
+			return r
+
+		query = urllib.parse.urlencode({"client_id": app["client_id"], "redirect_uri": OOB, "response_type": "code",
+										"scope": "read write follow"})
+		page = send("GET", f"/oauth/authorize?{query}").text
+		antiforgery = re.search(r'name="__RequestVerificationToken" value="([^"]+)"', page).group(1)
+		r = send("POST", f"/oauth/authorize?{query}", {
+			"_handler": "oauth-authorize", "__RequestVerificationToken": html.unescape(antiforgery),
+			"Model.Username": a.username, "Model.Password": a.password})
+		location = r.header("Location") or ""
+		code = urllib.parse.parse_qs(urllib.parse.urlsplit(location).query).get("code", [None])[0]
+		if code is None:
+			# the out-of-band page says "Your code is: <code>" in its text
+			text = re.sub(r"<[^>]+>", " ", re.sub(r"<(style|script).*?</\1>", "", r.text, flags=re.S))
+			found = re.search(r"Your code is:\s*([A-Za-z0-9_\-]{16,})", text)
+			code = found.group(1) if found else None
+		if code is None:
+			raise RuntimeError(f"Iceshrimp gave {a.username} no authorization code ({r.status}): {r.text[:300]}")
+		return self.http.post(self.base + "/oauth/token", ok={200}, form={
+			"grant_type": "authorization_code", "code": code, "client_id": app["client_id"],
+			"client_secret": app["client_secret"], "redirect_uri": OOB, "scope": "read write follow"}).json()["access_token"]
+
+	def react(self, s, uri, emoji):
+		sid = self.local_status_id(s, uri) or self.resolve(s, uri)
+		self.api(s, "POST", f"/api/v1/statuses/{sid}/react/{urllib.parse.quote(emoji)}", ok={200})
+
+	def _rows(self, uris):
+		if not uris:
+			return {}
+		local = {u: u.rsplit("/", 1)[1] for u in uris if u.startswith(f"{self.base}/notes/")}
+		rows = podman.psql("iceshrimp", f"""
+			select n.id, n.uri, n.visibility::text as visibility, n.text, n.cw, n."updatedAt" is not null as edited,
+				n."renoteCount" as boosts, n."repliesCount" as replies, n."likeCount" as likes, n.reactions, p.votes,
+				coalesce(r.uri, case when r.id is not null then '{self.base}/notes/' || r.id end) as parent_uri
+			from note n left join poll p on p."noteId" = n.id left join note r on r.id = n."replyId"
+			where (n."renoteId" is null or n.text is not null)
+				and (n.uri = any(string_to_array(:'p1', ' ')) or n.id = any(string_to_array(:'p2', ' ')))""",
+						   " ".join(uris), " ".join(local.values()) or "-")
+		out = {}
+		for r in rows:
+			uri = r["uri"] or f"{self.base}/notes/{r['id']}"
+			if uri not in uris:
+				continue
+			out[uri] = Stored(True, False, r["id"], VIS.get(r["visibility"], r["visibility"]), r["text"], r["cw"],
+							  bool(r["edited"]), r["parent_uri"], r["likes"], r["boosts"], r["replies"], r["votes"],
+							  r["reactions"] or {}, r)
+		return out