feat: hang-guard request() with an outer asyncio deadline

a backend can lose both its transfer wakeup and its own timeout enforcement in one
failure (observed: a curl_cffi request that parked an aioweb consumer's event loop for
24h+ - loop idle, nothing in flight, the await never completing). wrap _raw_request in
asyncio.wait_for at the effective timeout + 5s slack: the backend's own timeout still
fires first in every healthy failure, the envelope only trips when the backend's timer
is dead, and its cancellation unwedges the orphaned transfer. deadline = per-call numeric
timeout else the session timeout (default 10); timeout=None from request_with_retries
guards on the session bound (that was the wedge path). explicit Session(timeout=None)
stays unguarded - the documented opt-out for genuinely unbounded calls. additive, no new
knob. fired: a never-completing backend hangs forever without this, dies at deadline+slack
with it, and request_with_retries returns a FailureResponse instead of hanging.

Signed-off-by: disqualifier <dev@disqualifier.me>

.gitignore

@@ -1,5 +1,5 @@
 # claude
-CLAUDE.md
+.claude/
 
 # python
 __pycache__/

README.md

@@ -11,16 +11,19 @@ and swap the HTTP client while inheriting everything else.
 `requirements.txt`:
 
 ```
-aioweb @ git+ssh://git@git.rethinkstudios.io/rethink-public/aioweb.git@v0.1.3
+aioweb @ git+ssh://git@git.rethinkstudios.io/rethink-public/aioweb.git@v1.1.0
 ```
 
 Direct:
 
 ```bash
-pip install "aioweb @ git+ssh://git@git.rethinkstudios.io/rethink-public/aioweb.git@v0.1.3"
+pip install "aioweb @ git+ssh://git@git.rethinkstudios.io/rethink-public/aioweb.git@v1.1.0"
 ```
 
-Requires `aiohttp` and `yarl` (pulled transitively).
+Requires `aiohttp` and `yarl` (pulled transitively), plus the sibling `commons` library
+(a private `git+ssh` package — the install needs access to the `rethink-public` org).
+
+Drop the `@v1.1.0` suffix from the line above to install the latest unpinned.
 
 ## Usage
 
@@ -63,6 +66,15 @@ resp = await s.request_with_retries(
 
 Returns a `FailureResponse` (falsy) if every attempt fails.
 
+`request()` (the non-retrying call) raises on failure: a total timeout raises
+`aiohttp.ServerTimeoutError`, and any other network/protocol failure raises its real
+`aiohttp.ClientError` subtype as-is (`ClientConnectorError`, `ClientProxyConnectionError`,
+`ClientResponseError` with `.status`/`.headers`, `TooManyRedirects`, ...) — it is not
+flattened into the base `ClientError`, so direct callers can branch by type or read
+subtype attributes. `request_with_retries` catches the base `aiohttp.ClientError` (and
+`asyncio.TimeoutError`) across all attempts and returns a falsy `FailureResponse` instead
+of raising.
+
 ## Header overwrites & ephemeral headers
 
 ```python
@@ -86,7 +98,15 @@ s.overwrite_domain("internal.local", "127.0.0.1")   # host-substring rewrite
 print(s.preview("POST", url, json={"a": 1}).as_curl())   # equivalent cURL command
 ```
 
-Pass `debug=True` to `request_with_retries` to log the cURL preview and request flow.
+`preview()` is synchronous and never touches the backend session — it works before any
+event loop is running (e.g. building a preview at import/setup time), not just inside
+`asyncio.run()`. Its default cookie lookup only reads cookies from an already-built
+session; if the session hasn't been built yet there are no cookies to read, so it
+returns none by default (pass `cookies=` explicitly to preview cookies for a session
+that hasn't sent a request yet). `as_curl()` renders `params` (merged into the url's
+query string) and `timeout` (as `--max-time`) as well as headers/body/proxy, so the
+emitted command is faithful to what `request()` actually sends. Pass `debug=True` to
+`request_with_retries` to log the cURL preview and request flow.
 
 ## Custom backends
 
@@ -130,6 +150,123 @@ Two changes can't be shimmed without re-introducing the bugs they fix:
 
 ## Changelog
 
+### v1.1.0
+
+- **Hang-guard on `request()` — a wedged backend can no longer park the loop forever.**
+  `request()` now wraps the backend call (`_raw_request`) in an outer `asyncio.wait_for`
+  deadline sized at the effective timeout **+ 5s slack** (`_HANG_GUARD_SLACK`). The
+  backend's own timeout still fires first in every healthy failure (slack, not
+  replacement); the envelope only trips when the backend's timer is dead — e.g. a
+  `curl_cffi` transfer that loses both its wakeup and its own enforcement in the same
+  failure — and its cancellation is what unwedges the orphaned transfer. The guard's
+  deadline is the per-call numeric `timeout` when given, else the session timeout
+  (`Session(timeout=...)`, default 10s); it composes cleanly with `request_with_retries`
+  (a wedge becomes one logged `ServerTimeoutError`, the next attempt proceeds, and an
+  exhausted retry returns a `FailureResponse` rather than hanging). **Opt-out:** a
+  session deliberately constructed unbounded (`Session(timeout=None)`) stays unguarded,
+  for genuinely long-lived calls (long-poll / streaming). Additive; no new knob.
+
+### v0.1.13
+
+- **Session-default timeout no longer poisons pooled keep-alive connections.**
+  The default `ClientTimeout` set `sock_read=timeout/2` alongside `total`. Under
+  `aiohttp>=3.14`, that read timer re-arms on every request dispatched over a
+  pooled protocol, including idle connections between requests; when it fires
+  it permanently poisons the pooled connection (`SocketTimeoutError` on the next
+  use, instantly, without contacting the server) — a real error from the server
+  (e.g. a 503) could come back as a client-side `FailureResponse(status=0,
+  reason='timeout')` instead. `sock_read` is now dropped from the session
+  default; `total` (and `connect`/`sock_connect`) still bound every request, and
+  the per-call `timeout=N` path (`ClientTimeout(total=N)`, no `sock_read`) was
+  already unaffected.
+
+### v0.1.12
+
+- **Docstring-only.** Restored one-line docstrings on `FailureResponse`'s
+  `redirect_chain`, `text()`, `json()`, and `raise_for_status()` — a prior
+  de-bloat pass stripped them below the public tier while the `Response`
+  twins kept theirs. No behavior change.
+
+### v0.1.11
+
+- **`preview()` no longer requires a running event loop.** Its default cookie
+  lookup (`cookies=` not passed) previously called `_cookies_for_url()`, which
+  reached the backend session and built it if absent — under aiohttp>=3.14 that
+  needs a running loop, so `preview()` raised `RuntimeError('no running event
+  loop')` when called before the loop starts, defeating its own pre-loop
+  build/inspect use case (v0.1.7). Now the default cookie lookup is skipped
+  entirely when the session hasn't been built yet (nothing could have been set
+  on a session that doesn't exist); `cookies={}` and in-loop calls are unaffected.
+- **`set_cookie(domain=None)` now honors `path`.** The `domain=None` branch
+  returned right after `update_cookies()`, before the line that sets the
+  morsel's `path` — so a shared cookie (`set_cookie(name, value, path="/api")`,
+  no `domain=`) always stored the `SimpleCookie` default `path="/"` instead. The
+  morsel's `path` is now set before the `domain=None` early return. The
+  domain-bound branch was already correct and is unchanged.
+
+### v0.1.10
+
+- Docs-only pass: compressed module/method docstrings and comments that restated
+  README/CLAUDE prose, replaced em-dashes with hyphens. No behavior change.
+
+### v0.1.9
+
+- **`_get_proxy()`/`request()` proxy resolution now checks `is None`, not
+  truthiness.** A per-call `proxies={}` previously fell back to the session's
+  configured proxies instead of disabling them for that call. `request()` also no
+  longer clobbers a native `proxy=` kwarg with the resolved session/`proxies=`
+  value (a real IP-unmasking leak) — passing both now raises `ValueError` instead
+  of silently picking one.
+- **`Response.text(encoding=...)` no longer returns a stale cached decode.** A
+  second call with an explicit `encoding=` previously still returned the first
+  (possibly differently-encoded) cached decode; an explicit encoding now bypasses
+  the cache.
+- **`preview()` now rewrites the url before resolving cookies**, matching what
+  `request()` actually sends — previously cookies were resolved against the
+  pre-rewrite host, which could miss or misattribute host-bound cookies.
+- **`request_with_retries(attempts=0)` now floors to 1 attempt**, not silently
+  `DEFAULT_ATTEMPTS` (3). `attempts` is checked with `is None`, not truthiness.
+
+### v0.1.8
+
+- **`request()` no longer flattens `aiohttp.ClientError` subtypes.** Every failure
+  (connect errors, proxy errors, `raise_for_status()`-style response errors,
+  redirect limits, ...) was re-raised as a bare `aiohttp.ClientError`, losing the
+  real subtype and its attributes (`.os_error`, `.status`, `.headers`, ...) — a
+  direct caller doing `except ClientProxyConnectionError:` or `if e.status == 401`
+  would silently never match. Now the original exception is re-raised as-is (its
+  subtype, attributes, and `__cause__` all preserved). `request_with_retries`
+  still catches the base `aiohttp.ClientError` across attempts, so its behavior
+  (and its `FailureResponse` return on exhaustion) is unchanged.
+- **`as_curl()` now renders `params` and `timeout`.** Previously a preview built
+  with `params=` silently omitted the query string (and a `timeout=` omitted
+  `--max-time`), so a `debug=True` cURL replay of a params-driven request hit a
+  different URL than the one actually sent. `params` are now merged into the url's
+  query string (via `yarl`) and `timeout` is emitted as `--max-time`.
+
+### v0.1.7
+
+- **`get_cookies()` now returns real cookies.** Previously called `filter_cookies()`
+  with no URL, which only ever returns domain-less shared cookies — every normal
+  domain-bound cookie (including ones set by a real `Set-Cookie` response) was
+  silently omitted. Now iterates the jar directly.
+- **`set_cookie()` no longer leaks a shared cookie to every host.** A bare hostname
+  (`domain="example.com"`) built a schemeless URL, which aiohttp's jar treats as a
+  domain-less "shared" cookie sent with every request the session makes, including
+  unrelated hosts. A scheme is now added when missing so the cookie is scoped to
+  that host.
+- **`set_cookie()` now honors `path`** (previously ignored — the cookie always
+  landed at `path="/"`). `domain=None` is unchanged in meaning but now stores a
+  truly shared cookie (sent to every host) instead of one silently bound to
+  `localhost` only, which made `set_cookie(name, value)` (no domain) a silent
+  no-op for any real request.
+- **The backend session is built lazily**, not in `__init__`. Under aiohttp 3.14,
+  constructing `aiohttp.ClientSession` requires a running event loop; eager
+  construction crashed the common host pattern of attaching a session before the
+  loop starts (e.g. `bot.http = ExtendedSession(...)` in `Bot.__init__`). The
+  session (and any subclass's `_create_session` override) now builds on first
+  access instead.
+
 ### v0.1.2
 
 - Pinned `commons` to v0.2.1 (retry `attempts` floor fix).
@@ -147,4 +284,4 @@ Two changes can't be shimmed without re-introducing the bugs they fix:
 
 ## Versioning
 
-Tagged `vX.Y.Z`. Pin the tag in `requirements.txt`.
+Releases are tagged `vX.Y.Z`. The install line above pins a release; drop the `@vX.Y.Z` suffix to install the latest unpinned. Pin deliberately for reproducible installs.

pyproject.toml

@@ -4,13 +4,13 @@ build-backend = "hatchling.build"
 
 [project]
 name = "aioweb"
-version = "0.1.3"
+version = "1.1.0"
 description = "Async HTTP session wrapper over aiohttp — proxies, header overwrites, retries, previews. Config-free, installable."
 requires-python = ">=3.10"
 dependencies = [
     "aiohttp>=3.9",
     "yarl>=1.9",
-    "commons @ git+ssh://git@git.rethinkstudios.io/rethink-public/commons.git@v0.2.1",
+    "commons @ git+https://git.rethinkstudios.io/rethink-public/commons.git@v1.0.0",
 ]
 
 [tool.hatch.metadata]

src/aioweb/__init__.py

@@ -1,7 +1,14 @@
+from importlib.metadata import version, PackageNotFoundError
+
 from .session import ExtendedSession, DEFAULT_ATTEMPTS, RETRY_STATUSES
 from .responses import Response, FailureResponse, AiowebError, aiowebResponse
 from .preview import RequestPreview
 
+try:
+    __version__ = version("aioweb")
+except PackageNotFoundError:
+    __version__ = "0.0.0+unknown"
+
 __all__ = [
     "ExtendedSession",
     "Response",
@@ -17,17 +24,11 @@ __all__ = [
 
 
 async def request_retries(session, method, url, **kwargs):
-    """back-compat wrapper for session.request_with_retries(...)
-
-    prefer calling session.request_with_retries(...) directly.
-    """
+    """back-compat wrapper for session.request_with_retries(...); prefer calling that directly"""
     return await session.request_with_retries(method, url, **kwargs)
 
 
 async def test_proxies(session, url="https://api.ipify.org?format=json"):
-    """fetch the public IP via the session (verifies proxy config)
-
-    url defaults to ipify; pass another IP-echo endpoint to point elsewhere.
-    """
+    """fetch the public IP via the session (verifies proxy config); url defaults to ipify"""
     response = await session.request("GET", url)
     return response.json()

src/aioweb/preview.py

@@ -1,9 +1,12 @@
 """
-request preview for aioweb — format or export a request without sending it
+request preview for aioweb - format or export a request without sending it
 """
 
 import json as _json
 import shlex
+from urllib.parse import urlencode
+
+from yarl import URL
 
 
 class RequestPreview:
@@ -26,20 +29,26 @@ class RequestPreview:
         return "\n".join(f"{key}: {value}" for key, value in self.details.items())
 
     def as_curl(self):
-        """equivalent cURL command for the request
-
-        every interpolated value is shell-quoted with shlex.quote, so headers,
-        body, url, or proxy containing quotes/spaces/metacharacters produce a
-        valid, non-injectable command rather than a broken or unsafe one.
-        """
+        """equivalent cURL command for the request (values shlex.quote'd; matches what request() sends)"""
         parts = [f"curl -X {shlex.quote(self.details['method'])}"]
         for header, value in (self.details["headers"] or {}).items():
             parts.append(f"-H {shlex.quote(f'{header}: {value}')}")
-        if self.details["data"]:
-            parts.append(f"--data {shlex.quote(str(self.details['data']))}")
-        elif self.details["json"]:
+        if self.details["data"] is not None:
+            data = self.details["data"]
+            # aiohttp form-encodes a dict data= body (application/x-www-form-urlencoded);
+            # render that wire form, not the python repr, so the curl replays identically.
+            # doseq=True mirrors aiohttp's FormData: a list value becomes repeated k=v pairs
+            rendered = urlencode(data, doseq=True) if isinstance(data, dict) else str(data)
+            parts.append(f"--data {shlex.quote(rendered)}")
+        elif self.details["json"] is not None:
+            # is-not-None: an empty-but-valid body ({} / []) must still render
             parts.append(f"--data {shlex.quote(_json.dumps(self.details['json']))}")
-        parts.append(shlex.quote(str(self.details["url"])))
+        url = self.details["url"]
+        if self.details["params"]:
+            url = str(URL(url).update_query(self.details["params"]))
+        parts.append(shlex.quote(str(url)))
         if self.details["proxy"]:
             parts.append(f"--proxy {shlex.quote(str(self.details['proxy']))}")
+        if self.details["timeout"] is not None:
+            parts.append(f"--max-time {shlex.quote(str(self.details['timeout']))}")
         return " \\\n  ".join(parts)

src/aioweb/responses.py

@@ -1,10 +1,7 @@
 """
-backend-agnostic response objects for aioweb
-
-Response is built from primitives (status, headers, content, url, history) rather
-than holding a raw aiohttp object, so any backend can produce one. FailureResponse
-mirrors the same surface so callers can branch uniformly — every status/predicate is
-a property on both.
+backend-agnostic response objects for aioweb - Response and FailureResponse share
+the same surface (every status/predicate a property on both) so callers can branch
+uniformly regardless of which one they got.
 """
 
 import json as _json
@@ -34,32 +31,26 @@ class Response:
 
     @property
     def status_code(self) -> int:
-        """HTTP status code"""
         return self._status_code
 
     @property
     def headers(self):
-        """response headers"""
         return self._headers
 
     @property
     def url(self) -> str:
-        """final URL after redirects"""
         return self._url
 
     @property
     def reason(self):
-        """reason phrase for the status code"""
         return self._reason
 
     @property
     def cookies(self):
-        """cookies set in the response"""
         return self._cookies
 
     @property
     def history(self):
-        """redirect history (list of (status, url) tuples)"""
         return self._history
 
     @property
@@ -69,30 +60,31 @@ class Response:
 
     @property
     def is_redirect(self) -> bool:
-        """whether the status is a redirect"""
         return self._status_code in (301, 302, 303, 307, 308)
 
     @property
     def is_success(self) -> bool:
-        """whether the status indicates success (2xx)"""
         return 200 <= self._status_code < 300
 
     @property
     def content(self) -> bytes:
-        """raw response bytes"""
         return self._content
 
     def text(self, encoding: Optional[str] = None) -> str:
-        """decoded text content (cached)"""
+        """decoded text content, cached only for the default encoding"""
+        if encoding is not None:
+            return self._content.decode(encoding)
         if self._text is None:
-            self._text = self._content.decode(encoding or self._encoding)
+            self._text = self._content.decode(self._encoding)
         return self._text
 
     def json(self):
         """parsed JSON content, or None if not valid JSON"""
         try:
             return _json.loads(self.text())
-        except _json.JSONDecodeError:
+        except (_json.JSONDecodeError, UnicodeDecodeError):
+            # text() decodes the body and can raise UnicodeDecodeError on a non-UTF-8
+            # payload - that's a "not valid JSON" outcome, not an error to propagate
             return None
 
     def raise_for_status(self):
@@ -141,6 +133,7 @@ class FailureResponse:
 
     @property
     def redirect_chain(self):
+        """list of (status, url) tuples for all redirects"""
         return []
 
     @property
@@ -156,12 +149,15 @@ class FailureResponse:
         return None
 
     def text(self, encoding=None):
+        """always None"""
         return None
 
     def json(self):
+        """always None"""
         return None
 
     def raise_for_status(self):
+        """raise AiowebError(reason)"""
         raise AiowebError(self._reason)
 
     def __bool__(self) -> bool:
@@ -171,5 +167,5 @@ class FailureResponse:
         return f"<FailureResponse [{self._status_code}] {self._reason}>"
 
 
-# back-compat alias — the response class was renamed Response
+# back-compat alias - the response class was renamed Response
 aiowebResponse = Response

src/aioweb/session.py

@@ -1,25 +1,18 @@
 """
-async HTTP session wrapper over aiohttp
-
-ExtendedSession adds session-level proxies, header overwrites, ephemeral
-(per-request generated) headers, domain rewriting, request previews, and
-retry/backoff on top of aiohttp. The actual byte-sending is isolated in
-_raw_request() so a different backend (e.g. a TLS-fingerprinting client) can
-subclass and override just that one method, inheriting everything else.
+async HTTP session wrapper over aiohttp - proxies, header overwrites, ephemeral
+headers, domain rewriting, previews, retry/backoff. See README for usage and contract.
 
     async with ExtendedSession(proxies={"https": "http://..."}) as s:
         resp = await s.request_with_retries("GET", url)
         if resp:                       # FailureResponse is falsy
             data = resp.json()
-
-config-free: proxies/headers/timeouts are passed at construction or per call.
-sessions must be closed explicitly (async with, or await s.close()); there is no
-__del__ auto-close (that pattern is unsafe for async resources).
 """
 
 import asyncio
+import ipaddress
 import logging
 import warnings
+from http.cookies import SimpleCookie
 
 import aiohttp
 from yarl import URL
@@ -30,23 +23,35 @@ from .responses import Response, FailureResponse
 
 
 def _route_body(data):
-    """split a body into (data=, json=) kwargs
-
-    dict OR list bodies are valid JSON and route to json=; everything else
-    (str/bytes/form) routes to data=. previously only dicts went to json=, so a
-    JSON list was wrongly form-encoded.
-    """
+    """split a body into (data=, json=) kwargs; dict OR list routes to json=, else data="""
     if isinstance(data, (dict, list)):
         return None, data
     return data, None
 
 
-class _RetryStatus(Exception):
-    """internal signal: a retryable HTTP status; carries the real Response
+def _is_ip_host(host) -> bool:
+    """whether host is a literal IPv4/IPv6 address rather than a hostname"""
+    if not host:
+        return False
+    try:
+        ipaddress.ip_address(host)
+    except ValueError:
+        return False
+    return True
 
-    raised inside an attempt so commons.aretry drives the backoff + cap; the caller
-    catches the final one to return the REAL last response, not a synthetic failure.
-    """
+
+def _is_ipv6_literal(host) -> bool:
+    """whether host is a bare IPv6 literal (must be a whole-host swap, never a substring splice)"""
+    if not host:
+        return False
+    try:
+        return isinstance(ipaddress.ip_address(host), ipaddress.IPv6Address)
+    except ValueError:
+        return False
+
+
+class _RetryStatus(Exception):
+    """internal signal: a retryable HTTP status; carries the real Response through aretry"""
 
     def __init__(self, response):
         super().__init__(f"retryable status {response.status_code}")
@@ -57,8 +62,8 @@ log = logging.getLogger(__name__)
 
 DEFAULT_ATTEMPTS = 3
 DEFAULT_BACKOFF_BASE = 2.0
-# statuses worth retrying: rate limit + transient server errors
 RETRY_STATUSES = frozenset({429, 500, 502, 503, 504})
+_HANG_GUARD_SLACK = 5
 
 
 class ExtendedSession:
@@ -84,31 +89,43 @@ class ExtendedSession:
         self.domain_overwrites = domain_overwrites or {}
         self.ephemeral_headers = {}
         self.proxies = proxies or {}
-        # track our own default headers instead of touching aiohttp privates
+        # own header layer, not aiohttp privates, so update_headers/clear_headers work
         self._default_headers = dict(headers or {})
-        self.session = self._create_session(self._default_headers, timeout, **kwargs)
+        self._session_timeout = timeout
+        self._session_kwargs = kwargs
+        # aiohttp>=3.14 needs a running loop to build ClientSession; built lazily instead
+        self._session = None
+
+    @property
+    def session(self):
+        """the backend session, built lazily on first access (needs a running loop)"""
+        self._ensure_session()
+        return self._session
+
+    def _ensure_session(self):
+        """build the backend session on first use - idempotent"""
+        if self._session is None:
+            self._session = self._create_session(
+                self._default_headers, self._session_timeout, **self._session_kwargs,
+            )
 
     def _create_session(self, headers, timeout, **kwargs):
-        """create the backend HTTP session — override to use a different client
+        """create the backend HTTP session - override to swap HTTP clients
 
-        a subclass swapping the HTTP backend (e.g. a TLS-fingerprinting client)
-        overrides this to return its own session object. the overwrite/domain/
-        proxy/retry/preview logic in this class never touches the session object
-        directly (only _raw_request, the cookie methods, and close do), so those
-        features work unchanged on any backend.
+        `headers` isn't baked in here - aiohttp would copy it into an immutable map
+        update_headers/clear_headers can't touch; `_default_headers` is the mutable
+        layer request()/preview() merge per call instead.
 
-        `headers` is the session-default header set; the default aiohttp backend
-        does NOT bake it into the ClientSession (which would copy it into an
-        immutable per-session map that update_headers/clear_headers can't touch).
-        instead `_default_headers` is our own mutable layer that request() and
-        preview() merge per call, so the mutable session-header API actually works.
-        a backend that needs the defaults baked at construction may use `headers`.
+        no `sock_read` here - aiohttp re-arms that timer on every request dispatched
+        over a pooled protocol, including idle keep-alive connections, and firing it
+        calls `set_exception(SocketTimeoutError)` on the protocol, permanently
+        poisoning that pooled connection; the next request on it fails instantly
+        without contacting the server. `total` still bounds every request overall.
         """
         return aiohttp.ClientSession(
             timeout=aiohttp.ClientTimeout(
                 total=timeout,
                 connect=timeout / 2,
-                sock_read=timeout / 2,
                 sock_connect=timeout / 2,
             ),
             **kwargs,
@@ -124,10 +141,12 @@ class ExtendedSession:
     def _apply_overwrites(self, request_headers):
         """apply static overwrites and ephemeral headers to a request's headers"""
         request_headers = dict(request_headers or {})
-        for header, value in self.header_overwrites.items():
+        # list()-snapshot so a concurrent mutation of the shared dicts can't raise
+        # "dict changed size during iteration"
+        for header, value in list(self.header_overwrites.items()):
             if self.inject or header in request_headers:
                 request_headers[header] = value
-        for header, value_callable in self.ephemeral_headers.items():
+        for header, value_callable in list(self.ephemeral_headers.items()):
             if self.inject or header in request_headers:
                 value = value_callable()
                 if isinstance(value, dict):
@@ -178,16 +197,47 @@ class ExtendedSession:
     #   domain overwrites
 
     def overwrite_domain(self, target, replacement):
-        """register a host-substring rewrite (target -> replacement)"""
+        """register a host rewrite (target -> replacement)
+
+        raises ValueError if the replacement is not a valid host for yarl's with_host()
+        (e.g. a 'host:port' string or a pre-bracketed '[::1]') - caught here rather than
+        deep in yarl at request time. a bare IPv6 literal ('::1', '2001:db8::1') is valid
+        and accepted: yarl brackets it itself.
+
+        a hostname/IPv4 replacement rewrites any host CONTAINING target (substring splice,
+        e.g. 'example.com' -> 'internal.example.com'). an IPv6 replacement can only ever be
+        a WHOLE-HOST swap - splicing '::1' into the middle of a name yields an invalid host
+        ('internal::1') - so at request time an IPv6 replacement applies ONLY when target
+        equals the whole request host; a request whose host merely CONTAINS the target (a
+        substring) is left unrewritten instead of composing an invalid host and exploding
+        deep in yarl. see _apply_domain_overwrites.
+        """
+        try:
+            URL("http://placeholder").with_host(replacement)
+        except ValueError as exc:
+            raise ValueError(
+                f"overwrite_domain replacement {replacement!r} is not a valid host: {exc}; "
+                "pass a bare hostname or IP (a bare IPv6 literal is fine), not a host:port or "
+                "bracketed form - rewrite a port via a full URL override, not domain_overwrites"
+            ) from exc
         self.domain_overwrites[target] = replacement
 
     def _apply_domain_overwrites(self, url: str) -> str:
-        """apply any host-substring rewrites to a url"""
+        """apply any host rewrites to a url
+
+        a hostname/IPv4 replacement splices on a substring match; an IPv6 replacement only
+        applies on a whole-host (exact) match, since it can't be spliced mid-host - this pairs
+        with overwrite_domain's registration guard so an IPv6 rewrite never composes an
+        invalid host.
+        """
         parsed = URL(url)
         if not parsed.host:
             return url
         for target, replacement in self.domain_overwrites.items():
-            if target in parsed.host:
+            if _is_ipv6_literal(replacement):
+                if target == parsed.host:
+                    return str(parsed.with_host(replacement))
+            elif target in parsed.host:
                 return str(parsed.with_host(parsed.host.replace(target, replacement)))
         return url
 
@@ -205,8 +255,13 @@ class ExtendedSession:
         self.proxies.clear()
 
     def _get_proxy(self, url, proxies=None):
-        """resolve the proxy for a url's scheme"""
-        proxies = proxies or self.proxies
+        """resolve the proxy for a url's scheme
+
+        proxies is checked with `is None`, not truthiness, so an explicit
+        proxies={} disables session proxies for that one call instead of
+        falling back to them.
+        """
+        proxies = self.proxies if proxies is None else proxies
         scheme = url.split("://")[0]
         return proxies.get(scheme)
 
@@ -214,31 +269,89 @@ class ExtendedSession:
     #   cookies
 
     def get_cookies(self):
-        """cookies stored in the session jar"""
-        return self.session.cookie_jar.filter_cookies()
+        """all cookies in the session jar, regardless of domain binding
+
+        iterates the jar directly rather than filter_cookies() (which needs a url and,
+        given none, returns only domain-less shared cookies - {} for any normal one).
+        returns {} off-loop when no session was built yet (nothing could be set), mirroring
+        preview() - reaching self.session would build it and need a running loop.
+        """
+        if self._session is None:
+            return {}
+        return {c.key: c.value for c in self.session.cookie_jar}
 
     def set_cookie(self, name, value, domain=None, path="/"):
-        """set a cookie in the session jar"""
-        response_url = URL(domain or "http://localhost")
-        self.session.cookie_jar.update_cookies({name: value}, response_url=response_url)
+        """set a cookie in the session jar
+
+        domain=None stores a truly shared cookie sent to every host. domain='example.com'
+        (scheme optional, defaulted to http://) scopes it to that host - a bare hostname
+        is normalized into a URL so the jar binds by host instead of silently storing
+        another domain-less shared cookie. `path` is honored via the morsel itself.
+
+        raises:
+            ValueError: if domain is a bare IP host (e.g. '127.0.0.1') and the jar is
+                the default aiohttp.CookieJar(unsafe=False), which drops cookies bound
+                to IP hosts with no store, no send, and no log - construct the session
+                with cookie_jar=aiohttp.CookieJar(unsafe=True) to allow IP-host cookies
+        """
+        if self._session is None:
+            try:
+                self._ensure_session()
+            except RuntimeError as error:
+                raise RuntimeError(
+                    "set_cookie needs the backend cookie jar, which builds on first use and "
+                    "requires a running event loop; call it inside an async context (unlike "
+                    "get_cookies/clear_cookies, which no-op off-loop)"
+                ) from error
+        cookie = SimpleCookie()
+        cookie[name] = value
+        cookie[name]["path"] = path
+        if domain is None:
+            self.session.cookie_jar.update_cookies(cookie)
+            return
+        if "://" not in domain:
+            domain = "http://" + domain
+        url = URL(domain)
+        jar = self.session.cookie_jar
+        if _is_ip_host(url.raw_host) and not getattr(jar, "unsafe", False):
+            raise ValueError(
+                f"set_cookie domain {domain!r} resolves to a bare IP host, but "
+                "aiohttp's cookie jar rejects IP-address domains under unsafe=False "
+                "(the default) - the cookie would be silently dropped; construct "
+                "ExtendedSession with cookie_jar=aiohttp.CookieJar(unsafe=True) to "
+                "allow IP-host cookies"
+            )
+        jar.update_cookies(cookie, response_url=url)
 
     def clear_cookies(self):
-        """clear the session cookie jar"""
+        """clear the session cookie jar
+
+        a no-op off-loop when no session was built yet (an unbuilt jar is already empty),
+        so callers can clear before the loop starts without a spurious session build.
+        """
+        if self._session is None:
+            return
         self.session.cookie_jar.clear()
 
     def _cookies_for_url(self, url):
-        """dict of cookies the backend would send for url — override per backend
-
-        used by preview(). non-aiohttp backends override this (or return {}); the
-        rest of preview (domain rewrites, header overwrites) is backend-agnostic.
-        """
+        """dict of cookies the backend would send for url - override per backend (used by preview())"""
         return {k: v.value for k, v in self.session.cookie_jar.filter_cookies(URL(url)).items()}
 
     # -------------------------------------------------------------------------
     #   preview
 
     def preview(self, method, url, **kwargs):
-        """build a RequestPreview for a request without sending it"""
+        """build a RequestPreview for a request without sending it - synchronous, no loop required
+
+        url is domain-rewritten before cookies are resolved, matching the real
+        request - cookie binding is host-based, so resolving against the pre-rewrite
+        host could miss or misattribute cookies. the default cookie lookup never
+        touches the backend session: building it needs a running loop (aiohttp>=3.14),
+        which would defeat preview()'s own pre-loop inspection use case, and an unbuilt
+        session has no cookies to report anyway - pass cookies= explicitly to preview
+        cookies that would come from a not-yet-built session.
+        """
+        url = self._apply_domain_overwrites(url)
         proxy = self._get_proxy(url, kwargs.pop("proxies", None))
         merged = {**self._default_headers, **(kwargs.pop("headers", None) or {})}
         headers = self._apply_overwrites(merged)
@@ -247,7 +360,7 @@ class ExtendedSession:
         timeout_total = timeout if isinstance(timeout, (int, float)) else None
 
         cookies = kwargs.pop("cookies", None)
-        if cookies is None:
+        if cookies is None and self._session is not None:
             cookies = self._cookies_for_url(url)
         if cookies:
             cookie_header = "; ".join(f"{k}={v}" for k, v in cookies.items())
@@ -257,7 +370,7 @@ class ExtendedSession:
 
         return RequestPreview(
             method=method,
-            url=self._apply_domain_overwrites(url),
+            url=url,
             headers=headers,
             proxy=proxy,
             data=kwargs.get("data"),
@@ -272,10 +385,9 @@ class ExtendedSession:
     async def _raw_request(self, method, url, **kwargs) -> Response:
         """send one request with aiohttp and adapt it into a Response
 
-        this is the backend seam: a subclass can override only this method (using a
-        different HTTP client, e.g. a TLS-fingerprinting one), building a Response
-        from that backend's primitives. everything else (overwrites, retries,
-        preview) is inherited.
+        the backend seam: a subclass overrides only this to swap HTTP clients,
+        building a Response from that backend's primitives; everything else
+        (overwrites, retries, preview) is inherited.
         """
         response = await self.session.request(method, url, **kwargs)
         async with response:
@@ -292,8 +404,21 @@ class ExtendedSession:
             )
 
     async def request(self, method, url, **kwargs) -> Response:
-        """make a request, applying overwrites/domain rewrites/proxy resolution"""
-        kwargs["proxy"] = self._get_proxy(url, kwargs.pop("proxies", None))
+        """make a request, applying overwrites/domain rewrites/proxy resolution
+
+        raises the real exception subtype on failure (ServerTimeoutError on a total
+        timeout; any other aiohttp.ClientError re-raised as-is, not flattened, so
+        callers can branch by type or read subtype attributes like .status/.headers).
+        a native proxy= is never silently clobbered by resolved proxies= (that would
+        unmask the caller's real IP) - pass only one of them.
+        """
+        resolved_proxy = self._get_proxy(url, kwargs.pop("proxies", None))
+        if kwargs.get("proxy") is not None and resolved_proxy is not None:
+            raise ValueError("pass only one of proxy= or proxies= (session/per-call), not both")
+        # a bare proxy=None must not shadow a resolved proxies= (that would send direct and
+        # unmask the caller's IP); setdefault can't fix it because the None key already exists
+        if kwargs.get("proxy") is None:
+            kwargs["proxy"] = resolved_proxy
         debug = kwargs.pop("debug", False)
 
         merged = {**self._default_headers, **(kwargs.get("headers") or {})}
@@ -301,23 +426,55 @@ class ExtendedSession:
         kwargs["headers"] = {str(k): str(v) for k, v in kwargs["headers"].items()}
 
         timeout = kwargs.get("timeout")
+        # the hang-guard deadline, captured as a bare number BEFORE the ClientTimeout
+        # conversion below consumes it: a per-call numeric timeout, else the session
+        # default. a timeout=None (omitted, or the explicit None request_with_retries
+        # passes) means "use the session bound" - so it guards on self._session_timeout,
+        # NOT unguarded. the ONLY unguarded case is a session deliberately constructed
+        # unbounded (Session(timeout=None) -> self._session_timeout is None): the
+        # documented opt-out for a genuinely unbounded call (long-poll/streaming).
+        if isinstance(timeout, (int, float)):
+            guard_secs = timeout
+        else:
+            guard_secs = self._session_timeout
         if isinstance(timeout, (int, float)):
             kwargs["timeout"] = aiohttp.ClientTimeout(total=timeout)
+        elif timeout is None and "timeout" in kwargs:
+            # explicit timeout=None would reach aiohttp as ClientTimeout(total=None) -
+            # infinite, disabling the session default - so drop it instead (matters for
+            # request_with_retries, whose timeout kwarg defaults to None)
+            del kwargs["timeout"]
 
         url = self._apply_domain_overwrites(url)
         if debug:
             log.info("sending request to: %s", url)
 
         try:
+            # hang-guard: an outer asyncio deadline (session/curl timers can die in the
+            # same failure that parks the transfer - a backend that loses both wakeup and
+            # its own timeout enforcement would otherwise leave this await parked forever).
+            # the backend's own timeout still fires first in every healthy failure (slack,
+            # not replacement); wait_for only trips when the backend's enforcement is dead,
+            # and its cancellation is what unwedges the orphaned transfer.
+            if guard_secs is not None:
+                result = await asyncio.wait_for(
+                    self._raw_request(method, url, **kwargs), guard_secs + _HANG_GUARD_SLACK
+                )
+            else:
                 result = await self._raw_request(method, url, **kwargs)
             if debug and result.redirect_chain:
                 log.info("redirect chain: %s", result.redirect_chain)
             return result
-        except (aiohttp.ClientError, asyncio.TimeoutError) as error:
-            # a total ClientTimeout raises a bare asyncio.TimeoutError, which is NOT an
-            # aiohttp.ClientError subclass — wrap it into the same typed path so direct
-            # callers get a consistent failure instead of a raw timeout
-            raise aiohttp.ClientError(f"client error for {url}: {error}") from error
+        except asyncio.TimeoutError as error:
+            # not an aiohttp.ClientError subclass - wrap as ServerTimeoutError so callers
+            # get a typed failure and request_with_retries can label it a timeout. now also
+            # catches the hang-guard firing (asyncio.wait_for raises asyncio.TimeoutError).
+            raise aiohttp.ServerTimeoutError(f"timeout for {url}: {error}") from error
+        except aiohttp.ClientError as error:
+            # re-raise the original subtype (not flattened) - request_with_retries still
+            # catches the base aiohttp.ClientError below and is unaffected
+            log.error("client error for %s: %s", url, error)
+            raise
 
     async def request_with_retries(
         self, method, url, *, data=None, proxies=None, timeout=None, attempts=None,
@@ -328,9 +485,11 @@ class ExtendedSession:
 
         returns a Response on success (or non-retryable status), or a falsy
         FailureResponse if every attempt fails. backoff is exponential
-        (backoff_base ** attempt).
+        (backoff_base ** attempt). timeout=None falls back to the session-level
+        timeout (see request()'s note on why explicit None is dropped, not passed
+        through). attempts=0 floors to 1 (via commons.aretry), not DEFAULT_ATTEMPTS.
         """
-        attempts = attempts or DEFAULT_ATTEMPTS
+        attempts = DEFAULT_ATTEMPTS if attempts is None else attempts
         body_data, body_json = _route_body(data)
 
         if debug:
@@ -361,6 +520,10 @@ class ExtendedSession:
             log.error("all %d attempts failed for %s (last status %s)",
                       attempts, url, exhausted.response.status_code)
             return exhausted.response
+        except asyncio.TimeoutError:
+            # catch before ClientError so a timeout is labeled as such, not generic
+            log.error("all %d attempts timed out for %s", attempts, url)
+            return FailureResponse(reason="timeout", url=url)
         except aiohttp.ClientError as error:
             log.error("all %d attempts failed for %s (client error: %s)", attempts, url, error)
             return FailureResponse(reason=f"client error: {error}", url=url)
@@ -372,12 +535,18 @@ class ExtendedSession:
     #   lifecycle
 
     async def close(self):
-        """close the backend session — override if the backend's close differs"""
-        await self.session.close()
+        """close the backend session - override if the backend's close differs; no-op if never built"""
+        if self._session is not None:
+            await self._session.close()
 
     def _is_closed(self) -> bool:
-        """whether the backend session is closed — override for non-aiohttp backends"""
-        return self.session.closed
+        """whether the backend session is closed - override for non-aiohttp backends
+
+        an unbuilt session counts as closed: nothing was opened, nothing to leak.
+        """
+        if self._session is None:
+            return True
+        return self._session.closed
 
     async def __aenter__(self):
         return self
@@ -386,8 +555,8 @@ class ExtendedSession:
         await self.close()
 
     def __del__(self):
-        # do NOT attempt async cleanup here — spinning event loops in a finalizer
-        # is unsafe. just warn so the leak is visible; callers must close explicitly.
+        # no async cleanup here - spinning event loops in a finalizer is unsafe;
+        # just warn so the leak is visible, callers must close explicitly
         try:
             closed = self._is_closed()
         except Exception: