Studio: ignore unsupported env proxy during Studio startup (#6102)

* fix: ignore unsupported env proxy during Studio startup

* fix: handle missing socksio env proxy at startup

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* Match printf logging style and inline the proxy predicate for PR #6102

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Daniel Han <danielhanchen@gmail.com>

studio/backend/core/inference/external_provider.py

@@ -469,9 +469,24 @@ def _apply_mistral_reasoning_controls(
 
 
 # Shared client reused across all requests for HTTP connection pooling.
-# Auth headers and timeouts are per-request, so one client handles every
-# provider without storing credentials.
-_http_client = httpx.AsyncClient()
+# Auth headers and timeouts are passed per-request, so a single client
+# handles every provider without storing credentials.
+def _create_shared_http_client() -> httpx.AsyncClient:
+    # Unsupported env proxy schemes (socks:// etc) raise at construction and
+    # would crash Studio startup (#6090); retry ignoring env proxies instead.
+    try:
+        return httpx.AsyncClient()
+    except (ImportError, ValueError) as exc:
+        exc_str = str(exc)
+        if "Unknown scheme for proxy URL" not in exc_str and "socksio" not in exc_str:
+            raise
+        logger.warning(
+            "Ignoring unsupported environment proxy for the shared HTTP client: %s", exc_str
+        )
+        return httpx.AsyncClient(trust_env = False)
+
+
+_http_client = _create_shared_http_client()
 
 
 # Cap per-image fetch well below Gemini's ~20 MB total request budget.

studio/backend/tests/test_external_provider_proxy_env.py

@@ -0,0 +1,80 @@
+# SPDX-License-Identifier: AGPL-3.0-only
+# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
+
+from pathlib import Path
+import importlib.util
+import sys
+
+_BACKEND_DIR = str(Path(__file__).resolve().parent.parent)
+if _BACKEND_DIR not in sys.path:
+    sys.path.insert(0, _BACKEND_DIR)
+
+_EXTERNAL_PROVIDER_PATH = (
+    Path(__file__).resolve().parent.parent / "core/inference/external_provider.py"
+)
+
+
+def _load_external_provider_module():
+    spec = importlib.util.spec_from_file_location(
+        "external_provider_under_test",
+        _EXTERNAL_PROVIDER_PATH,
+    )
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_shared_http_client_ignores_unsupported_proxy_scheme(monkeypatch):
+    ep_mod = _load_external_provider_module()
+    calls = []
+
+    class FakeAsyncClient:
+        def __init__(self, **kwargs):
+            calls.append(kwargs)
+            if kwargs.get("trust_env") is not False:
+                raise ValueError("Unknown scheme for proxy URL URL('socks4://127.0.0.1:12345')")
+
+    monkeypatch.setattr(ep_mod.httpx, "AsyncClient", FakeAsyncClient)
+
+    client = ep_mod._create_shared_http_client()
+
+    assert isinstance(client, FakeAsyncClient)
+    assert calls == [{}, {"trust_env": False}]
+
+
+def test_shared_http_client_ignores_missing_socksio(monkeypatch):
+    ep_mod = _load_external_provider_module()
+    calls = []
+
+    class FakeAsyncClient:
+        def __init__(self, **kwargs):
+            calls.append(kwargs)
+            if kwargs.get("trust_env") is not False:
+                raise ImportError(
+                    "Using SOCKS proxy, but the 'socksio' package is not installed. "
+                    "Make sure to install httpx using `pip install httpx[socks]`."
+                )
+
+    monkeypatch.setattr(ep_mod.httpx, "AsyncClient", FakeAsyncClient)
+
+    client = ep_mod._create_shared_http_client()
+
+    assert isinstance(client, FakeAsyncClient)
+    assert calls == [{}, {"trust_env": False}]
+
+
+def test_shared_http_client_reraises_other_value_errors(monkeypatch):
+    ep_mod = _load_external_provider_module()
+
+    class FakeAsyncClient:
+        def __init__(self, **kwargs):
+            raise ValueError("different httpx setup error")
+
+    monkeypatch.setattr(ep_mod.httpx, "AsyncClient", FakeAsyncClient)
+
+    try:
+        ep_mod._create_shared_http_client()
+    except ValueError as exc:
+        assert str(exc) == "different httpx setup error"
+    else:
+        raise AssertionError("expected ValueError")