fix(env-update): accept non-schema keys and preserve extras on round-trip

Two fixes for the .env write path:

1. Host agent: change strict reject (400) to warn-and-accept for keys
   not in .env.schema.json.  Extension install hooks and GPU pinning
   write keys that are absent from the core schema (e.g. JWT_SECRET
   from LibreChat, COMFYUI_GPU_UUID from the installer).  Rejecting
   them made the dashboard Settings save unusable after any extension
   install.

2. Dashboard API: _render_env_from_values no longer drops extras with
   empty values.  The filter `value != ""` silently discarded keys
   like LLAMA_ARG_TENSOR_SPLIT="" on round-trip, even though empty
   values are semantically meaningful (disabling a setting).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

dream-server/bin/dream-host-agent.py

@@ -676,10 +676,17 @@ def _handle_env_update(self):
                 return
             key, _, value = stripped.partition("=")
             key = key.strip()
-            if key not in allowed_keys:
-                logger.warning("env_update rejected: unknown key %r from %s", key, client_ip)
-                json_response(self, 400, {"error": f"Unknown key: {key}"})
+            if not re.match(r'^[A-Za-z_][A-Za-z0-9_]*$', key):
+                logger.warning("env_update rejected: invalid key name %r from %s", key[:40], client_ip)
+                json_response(self, 400, {"error": f"Invalid key name: {key[:40]}"})
                 return
+            if key not in allowed_keys:
+                # Warn but accept — extension install hooks and GPU pinning write
+                # keys that are not in the core schema (e.g. JWT_SECRET from
+                # LibreChat, COMFYUI_GPU_UUID from the installer).  Rejecting
+                # them breaks the dashboard Settings save for any install that
+                # has ever enabled an extension.
+                logger.info("env_update: non-schema key %r from %s (accepted)", key, client_ip)
             # Defense in depth: reject values containing control chars (null bytes,
             # escape sequences, etc.). splitlines() already consumed \n/\r/\u2028/\u2029;
             # this catches the residual edge cases flagged by security review.

dream-server/extensions/services/dashboard-api/main.py

@@ -709,7 +709,7 @@ def _render_env_from_values(values: dict[str, str]) -> str:
 
         output_lines.append(line)
 
-    extras = [(key, value) for key, value in values.items() if key not in seen and value != ""]
+    extras = [(key, value) for key, value in values.items() if key not in seen]
     if extras:
         if output_lines and output_lines[-1] != "":
             output_lines.append("")

dream-server/extensions/services/dashboard-api/tests/test_host_agent.py

@@ -325,14 +325,19 @@ def test_413_oversize_body(self, env_update_env):
         assert handler.response_code == 413
         assert "too large" in handler.parse_response()["error"].lower()
 
-    def test_400_unknown_key(self, env_update_env):
-        body = _make_body("NOT_IN_SCHEMA=foo\n")
+    def test_accepts_unknown_key_with_warning(self, env_update_env):
+        """Non-schema keys are accepted (warn, not reject) so extension-added
+        keys (e.g. JWT_SECRET from LibreChat) don't break Settings save."""
+        install_dir, data_dir = env_update_env
+        (install_dir / ".env").write_text("DREAM_AGENT_KEY=old\n", encoding="utf-8")
+        body = _make_body("DREAM_AGENT_KEY=old\nNOT_IN_SCHEMA=foo\n")
         handler = _FakeHandler(body)
 
         _mod.AgentHandler._handle_env_update(handler)
 
-        assert handler.response_code == 400
-        assert "Unknown key" in handler.parse_response()["error"]
+        assert handler.response_code == 200
+        env_text = (install_dir / ".env").read_text(encoding="utf-8")
+        assert "NOT_IN_SCHEMA=foo" in env_text
 
     def test_400_malformed_line(self, env_update_env):
         body = _make_body("THIS_LINE_HAS_NO_EQUALS\n")

dream-server/extensions/services/dashboard-api/tests/test_settings_env.py

@@ -287,3 +287,25 @@ def test_api_settings_env_apply_rejects_disallowed_service(test_client):
 
     assert response.status_code == 400
     assert "not eligible" in response.json()["detail"]["message"].lower()
+
+
+# --- Render round-trip fidelity ---
+
+
+def test_render_env_preserves_extras_with_empty_values():
+    """Keys with empty values must survive _render_env_from_values round-trip.
+
+    Regression guard for fork issue #335: the old filter
+    ``value != ""`` silently dropped keys like LLAMA_ARG_TENSOR_SPLIT=""
+    on every save.
+    """
+    from main import _render_env_from_values
+
+    values = {
+        "LLM_BACKEND": "local",
+        "TENSOR_SPLIT": "",       # intentionally empty
+        "GPU_UUID": "GPU-abc123",
+    }
+    rendered = _render_env_from_values(values)
+    assert "TENSOR_SPLIT=" in rendered
+    assert "GPU_UUID=GPU-abc123" in rendered