Convert httpx usage added on main since the last rebase to httpx2

New test files and comments picked up httpx imports on main; convert
them to httpx2 and re-apply the dependency swap to uv.lock (httpx,
httpx-sse, and httpcore out; httpx2, httpcore2, and truststore in;
idna raised to the 3.18 floor httpx2 requires).

No-Verification-Needed: test-only conversions plus lockfile, no runtime surface

Author: maxisbey

tests/client/test_client_caching.py

@@ -12,7 +12,7 @@
 
 import anyio
 import anyio.lowlevel
-import httpx
+import httpx2
 import mcp_types as types
 import pytest
 from inline_snapshot import snapshot
@@ -836,9 +836,9 @@ async def call_tool(ctx: ServerRequestContext, params: types.CallToolRequestPara
 
     server = Server("headers", on_list_tools=list_tools, on_call_tool=call_tool)
 
-    posts: list[httpx.Request] = []
+    posts: list[httpx2.Request] = []
 
-    async def on_request(request: httpx.Request) -> None:
+    async def on_request(request: httpx2.Request) -> None:
         posts.append(request)
 
     config = CacheConfig(store=InMemoryResponseCacheStore(), partition="p", target_id="svc")

tests/client/test_streamable_http.py

@@ -189,7 +189,7 @@ class _ParkedSSEStream(httpx2.AsyncByteStream):
     """An SSE response body that emits one comment line, then parks until closed.
 
     `opened` fires once the transport is iterating the body (the POST is truly in
-    flight); `closed` fires when httpx tears the body down — the observable proof
+    flight); `closed` fires when httpx2 tears the body down — the observable proof
     that an abort, not a response, ended the stream.
     """
 

tests/docs_src/test_deploy.py

@@ -1,7 +1,7 @@
 """`docs/run/deploy.md`: every claim the page makes, proved against the real SDK."""
 
 import anyio
-import httpx
+import httpx2
 import pytest
 from mcp_types import (
     INVALID_PARAMS,
@@ -44,18 +44,18 @@ async def test_the_default_app_rejects_a_real_hostname_before_mcp_runs() -> None
     bare = MCPServer("Notes")
     app = bare.streamable_http_app()
     async with bare.session_manager.run():
-        async with httpx.AsyncClient(transport=httpx.ASGITransport(app=app), base_url="https://api.example.com") as h:
+        async with httpx2.AsyncClient(transport=httpx2.ASGITransport(app=app), base_url="https://api.example.com") as h:
             response = await h.post("/mcp", json=INITIALIZE, headers=MCP_HEADERS)
     assert (response.status_code, response.text) == (421, "Invalid Host header")
 
 
 async def test_the_allowlisted_app_serves_its_hostname_and_still_rejects_others() -> None:
     """tutorial001: `allowed_hosts=` opens exactly the hostname you named, and nothing else."""
-    transport = httpx.ASGITransport(app=tutorial001.app)
+    transport = httpx2.ASGITransport(app=tutorial001.app)
     async with tutorial001.mcp.session_manager.run():
-        async with httpx.AsyncClient(transport=transport, base_url="https://mcp.example.com") as http:
+        async with httpx2.AsyncClient(transport=transport, base_url="https://mcp.example.com") as http:
             allowed = await http.post("/mcp", json=INITIALIZE, headers=MCP_HEADERS)
-        async with httpx.AsyncClient(transport=transport, base_url="https://api.example.com") as http:
+        async with httpx2.AsyncClient(transport=transport, base_url="https://api.example.com") as http:
             rejected = await http.post("/mcp", json=INITIALIZE, headers=MCP_HEADERS)
     assert allowed.status_code == 200
     assert allowed.headers["mcp-session-id"]

tests/docs_src/test_legacy_clients.py

@@ -2,7 +2,7 @@
 
 import inspect
 
-import httpx
+import httpx2
 import pytest
 from mcp_types import INVALID_REQUEST, ResourceUpdatedNotification, TextContent
 
@@ -64,8 +64,8 @@ async def test_a_legacy_session_is_minted_in_process_and_a_stray_session_id_is_a
     app = MCPServer("Bookshop").streamable_http_app()
     async with (
         app.router.lifespan_context(app),
-        httpx.ASGITransport(app) as transport,
-        httpx.AsyncClient(transport=transport, base_url="http://localhost:8000") as http,
+        httpx2.ASGITransport(app) as transport,
+        httpx2.AsyncClient(transport=transport, base_url="http://localhost:8000") as http,
     ):
         opened = await http.post("/mcp", json=INITIALIZE, headers=MCP_HEADERS)
         assert opened.status_code == 200
@@ -80,8 +80,8 @@ async def test_stateless_http_never_mints_a_session() -> None:
     app = MCPServer("Bookshop").streamable_http_app(stateless_http=True)
     async with (
         app.router.lifespan_context(app),
-        httpx.ASGITransport(app) as transport,
-        httpx.AsyncClient(transport=transport, base_url="http://localhost:8000") as http,
+        httpx2.ASGITransport(app) as transport,
+        httpx2.AsyncClient(transport=transport, base_url="http://localhost:8000") as http,
     ):
         opened = await http.post("/mcp", json=INITIALIZE, headers=MCP_HEADERS)
     assert opened.status_code == 200
@@ -93,8 +93,8 @@ async def test_stateless_http_kills_the_legacy_back_channel_and_only_the_legacy_
     the legacy client's call fails as the top-level `MCPError` the `!!! check` quotes."""
     async with (
         tutorial002.app.router.lifespan_context(tutorial002.app),
-        httpx.ASGITransport(tutorial002.app) as transport,
-        httpx.AsyncClient(transport=transport) as http,
+        httpx2.ASGITransport(tutorial002.app) as transport,
+        httpx2.AsyncClient(transport=transport) as http,
     ):
         modern_target = streamable_http_client(URL, http_client=http)
         async with Client(modern_target, elicitation_callback=tutorial001.answer) as modern:

tests/docs_src/test_troubleshooting.py

@@ -3,7 +3,7 @@
 import logging
 from typing import Any
 
-import httpx
+import httpx2
 import pytest
 from mcp_types import (
     INVALID_PARAMS,
@@ -125,10 +125,10 @@ async def test_the_default_streamable_http_app_answers_a_real_hostname_with_421(
     caplog: pytest.LogCaptureFixture,
 ) -> None:
     """tutorial003: one 421, three spellings. The page presents all three as the same event."""
-    transport = httpx.ASGITransport(app=tutorial003.app)
+    transport = httpx2.ASGITransport(app=tutorial003.app)
     async with tutorial003.mcp.session_manager.run():
         # What curl (or the reverse proxy's access log) shows: the status and the plain-text body.
-        async with httpx.AsyncClient(transport=transport, base_url="http://mcp.example.com") as raw:
+        async with httpx2.AsyncClient(transport=transport, base_url="http://mcp.example.com") as raw:
             with caplog.at_level(logging.WARNING, logger="mcp.server.transport_security"):
                 response = await raw.post("/mcp", json=INITIALIZE, headers=MCP_HEADERS)
         assert (response.status_code, response.text) == (421, "Invalid Host header")
@@ -137,7 +137,7 @@ async def test_the_default_streamable_http_app_answers_a_real_hostname_with_421(
         # What the server operator finds by grepping the server log.
         assert "Invalid Host header: mcp.example.com" in caplog.messages
         # What the python `Client` raises instead: the generic stand-in, wrapped by the task group.
-        async with httpx.AsyncClient(transport=transport) as http_client:
+        async with httpx2.AsyncClient(transport=transport) as http_client:
             client = Client(streamable_http_client("http://mcp.example.com/mcp", http_client=http_client))
             with pytest.raises(Exception) as exc_info:  # pragma: no branch
                 await client.__aenter__()  # the connection attempt itself is what fails
@@ -147,9 +147,9 @@ async def test_the_default_streamable_http_app_answers_a_real_hostname_with_421(
 
 async def test_an_allowlisted_hostname_connects_and_calls_a_tool() -> None:
     """tutorial004: `transport_security=` names the deployed hostname, and the same client connects."""
-    transport = httpx.ASGITransport(app=tutorial004.app)
+    transport = httpx2.ASGITransport(app=tutorial004.app)
     async with tutorial004.mcp.session_manager.run():
-        async with httpx.AsyncClient(transport=transport) as http_client:
+        async with httpx2.AsyncClient(transport=transport) as http_client:
             allowed = streamable_http_client("http://mcp.example.com/mcp", http_client=http_client)
             async with Client(allowed) as c:  # pragma: no branch
                 assert c.protocol_version == "2026-07-28"
@@ -159,8 +159,8 @@ async def test_an_allowlisted_hostname_connects_and_calls_a_tool() -> None:
 
 async def test_a_mounted_app_without_a_lifespan_fails_on_the_first_request() -> None:
     """tutorial005: Starlette never runs a mounted sub-app's lifespan, so nothing starts the manager."""
-    transport = httpx.ASGITransport(app=tutorial005.app)
-    async with httpx.AsyncClient(transport=transport, base_url="http://127.0.0.1:8000") as http:
+    transport = httpx2.ASGITransport(app=tutorial005.app)
+    async with httpx2.AsyncClient(transport=transport, base_url="http://127.0.0.1:8000") as http:
         with pytest.raises(RuntimeError, match=r"Task group is not initialized\. Make sure to use run\(\)\."):
             await http.post("/mcp")
 
@@ -170,7 +170,7 @@ async def test_a_session_id_the_server_never_issued_gets_a_404_session_not_found
     mcp = MCPServer("Weather")
     app = mcp.streamable_http_app()
     async with mcp.session_manager.run():
-        async with httpx.AsyncClient(transport=httpx.ASGITransport(app=app), base_url="http://127.0.0.1:8000") as h:
+        async with httpx2.AsyncClient(transport=httpx2.ASGITransport(app=app), base_url="http://127.0.0.1:8000") as h:
             response = await h.post(
                 "/mcp",
                 json={"jsonrpc": "2.0", "id": 1, "method": "tools/list", "params": {}},
@@ -243,9 +243,9 @@ async def test_a_legacy_ctx_elicit_without_a_callback_says_elicitation_not_suppo
 
 async def test_ctx_elicit_over_stateless_http_has_no_back_channel() -> None:
     """tutorial008: `stateless_http=True` leaves the server no channel to send `elicitation/create`."""
-    transport = httpx.ASGITransport(app=tutorial008.app)
+    transport = httpx2.ASGITransport(app=tutorial008.app)
     async with tutorial008.mcp.session_manager.run():
-        async with httpx.AsyncClient(transport=transport) as http_client:
+        async with httpx2.AsyncClient(transport=transport) as http_client:
             stateless = streamable_http_client("http://127.0.0.1:8000/mcp", http_client=http_client)
             async with Client(stateless) as c:  # pragma: no branch
                 with pytest.raises(MCPError) as exc_info:  # pragma: no branch

tests/server/test_streamable_http_modern.py

@@ -894,7 +894,7 @@ async def test_modern_tools_call_leaves_mis_shaped_name_and_arguments_to_dispatc
 
 async def test_modern_tools_call_rejects_a_duplicated_mcp_param_header() -> None:
     """A duplicated recognized header is rejected even if one copy matches: readers may disagree on which wins."""
-    # An httpx header list with a repeated name reaches the ASGI scope as two raw header lines.
+    # An httpx2 header list with a repeated name reaches the ASGI scope as two raw header lines.
     duplicated = httpx2.Headers(
         [*_TOOL_CALL_HEADERS.items(), ("mcp-param-region", "spoofed"), ("mcp-param-region", "eu")]
     )