fix(models): probe /v1/models for path-less LM Studio endpoints

Probe /v1/models for path-less OpenAI-compatible model endpoints and surface clearer LM Studio diagnostics with the actual probed URL.

tests/test_lmstudio_models_url.py

@@ -0,0 +1,160 @@
+"""Regression coverage for LM Studio /v1 model-list endpoints (issue #25).
+
+LM Studio's OpenAI-compatible surface exposes its model list at
+``/v1/models`` (just like llama-server, vLLM, text-generation-webui). Two
+distinct failure modes were reported by users:
+
+1. Pasting ``http://localhost:1234`` (no ``/v1``) — ``build_models_url``
+   used to return ``http://localhost:1234/models``, which LM Studio does
+   not expose, so the user got a generic "No models found" error even
+   though the server was running and reachable.
+2. Pasting ``http://localhost:1234/v1`` (with ``/v1``) — the model list
+   fetch was correct, but the error message gave the user no way to tell
+   whether the URL was wrong, the server was down, or the server was
+   reachable but had no model loaded.
+
+This module pins both behaviors so future refactors don't regress them.
+"""
+
+import httpx
+
+from src import endpoint_resolver, llm_core
+
+
+def _neutralize_provider_detection(monkeypatch):
+    """``_is_ollama_native_url`` matches any localhost host with an empty
+    path, which would route ``http://localhost:1234`` (LM Studio) into the
+    Ollama branch and probe ``/api/tags`` instead of ``/v1/models``. Force
+    provider detection to "openai" so the URL builder takes the LM Studio
+    path the user actually intends."""
+    monkeypatch.setattr(llm_core, "_is_ollama_native_url", lambda url: False)
+
+
+# ── build_models_url: handle LM Studio base shapes ────────────────────
+
+
+def test_build_models_url_inserts_v1_for_bare_host_port(monkeypatch):
+    """`http://localhost:1234` must probe `/v1/models` for LM Studio."""
+    monkeypatch.setattr(endpoint_resolver, "resolve_url", lambda url: url)
+    _neutralize_provider_detection(monkeypatch)
+
+    assert (
+        endpoint_resolver.build_models_url("http://localhost:1234")
+        == "http://localhost:1234/v1/models"
+    )
+
+
+def test_build_models_url_accepts_v1_base(monkeypatch):
+    """`http://localhost:1234/v1` must probe `/v1/models` (no double v1)."""
+    monkeypatch.setattr(endpoint_resolver, "resolve_url", lambda url: url)
+    _neutralize_provider_detection(monkeypatch)
+
+    assert (
+        endpoint_resolver.build_models_url("http://localhost:1234/v1")
+        == "http://localhost:1234/v1/models"
+    )
+
+
+def test_build_models_url_idempotent_for_explicit_models(monkeypatch):
+    """`/v1/models` must probe `/v1/models` (normalize_base strips it)."""
+    monkeypatch.setattr(endpoint_resolver, "resolve_url", lambda url: url)
+    _neutralize_provider_detection(monkeypatch)
+
+    assert (
+        endpoint_resolver.build_models_url("http://localhost:1234/v1/models")
+        == "http://localhost:1234/v1/models"
+    )
+
+
+def test_build_models_url_strips_chat_completions(monkeypatch):
+    """`/v1/chat/completions` must collapse to `/v1/models` (parity with #3330)."""
+    monkeypatch.setattr(endpoint_resolver, "resolve_url", lambda url: url)
+    _neutralize_provider_detection(monkeypatch)
+
+    assert (
+        endpoint_resolver.build_models_url("http://localhost:1234/v1/chat/completions")
+        == "http://localhost:1234/v1/models"
+    )
+
+
+def test_build_models_url_preserves_explicit_non_v1_path(monkeypatch):
+    """User-supplied non-empty paths (e.g. `/openai`) must not be overridden
+    with `/v1`. We only insert `/v1` when the path is empty — that matches
+    the documented contract: a custom path is the caller's intent."""
+    monkeypatch.setattr(endpoint_resolver, "resolve_url", lambda url: url)
+    _neutralize_provider_detection(monkeypatch)
+
+    assert (
+        endpoint_resolver.build_models_url("http://proxy.example.com/openai")
+        == "http://proxy.example.com/openai/models"
+    )
+
+
+# ── list_model_ids: parse LM Studio's response ─────────────────────────
+
+
+def test_llm_core_list_model_ids_queries_v1_models_for_lmstudio(monkeypatch):
+    """Issue #25: probing `http://localhost:1234/v1` must hit `/v1/models`."""
+    monkeypatch.setattr(endpoint_resolver, "resolve_url", lambda url: url)
+    monkeypatch.setattr(llm_core, "_configured_cached_model_ids", lambda url, **kwargs: [])
+    seen = []
+
+    def fake_get(url, headers=None, timeout=None):
+        seen.append(url)
+        request = httpx.Request("GET", url)
+        return httpx.Response(
+            200,
+            json={
+                "object": "list",
+                "data": [
+                    {"id": "lmstudio-community/Meta-Llama-3-8B-Instruct-GGUF"},
+                    {"id": "qwen2.5-7b-instruct"},
+                ],
+            },
+            request=request,
+        )
+
+    monkeypatch.setattr(llm_core.httpx, "get", fake_get)
+
+    assert llm_core.list_model_ids("http://localhost:1234/v1", timeout=1) == [
+        "lmstudio-community/Meta-Llama-3-8B-Instruct-GGUF",
+        "qwen2.5-7b-instruct",
+    ]
+    assert seen == ["http://localhost:1234/v1/models"]
+
+
+def test_llm_core_list_model_ids_queries_v1_models_for_bare_lmstudio(monkeypatch):
+    """Issue #25: probing `http://localhost:1234` (no /v1) must hit `/v1/models`."""
+    monkeypatch.setattr(endpoint_resolver, "resolve_url", lambda url: url)
+    monkeypatch.setattr(llm_core, "_configured_cached_model_ids", lambda url, **kwargs: [])
+    # Localhost with empty path would otherwise be misclassified as Ollama
+    # (llm_core._is_ollama_native_url); neutralise that for the test.
+    monkeypatch.setattr(llm_core, "_is_ollama_native_url", lambda url: False)
+    seen = []
+
+    def fake_get(url, headers=None, timeout=None):
+        seen.append(url)
+        request = httpx.Request("GET", url)
+        return httpx.Response(200, json={"data": [{"id": "model-a"}]}, request=request)
+
+    monkeypatch.setattr(llm_core.httpx, "get", fake_get)
+
+    assert llm_core.list_model_ids("http://localhost:1234", timeout=1) == ["model-a"]
+    assert seen == ["http://localhost:1234/v1/models"]
+
+
+def test_llm_core_list_model_ids_handles_empty_lmstudio_list(monkeypatch):
+    """LM Studio returns `{"object":"list","data":[]}` when no model is loaded.
+    The helper must return `[]` cleanly so the caller can surface a clear
+    error (issue #25: previously the empty case was indistinguishable from
+    a connection failure)."""
+    monkeypatch.setattr(endpoint_resolver, "resolve_url", lambda url: url)
+    monkeypatch.setattr(llm_core, "_configured_cached_model_ids", lambda url, **kwargs: [])
+
+    def fake_get(url, headers=None, timeout=None):
+        request = httpx.Request("GET", url)
+        return httpx.Response(200, json={"object": "list", "data": []}, request=request)
+
+    monkeypatch.setattr(llm_core.httpx, "get", fake_get)
+
+    assert llm_core.list_model_ids("http://localhost:1234/v1", timeout=1) == []