fix(gpu): respect dotenv override precedence and export prefix in env reader

.github/workflows/test-linux.yml

@@ -402,6 +402,7 @@ jobs:
           bash tests/test-preflight-resolver-bug.sh
           bash tests/test-desktop-agent-host-env.sh
           bash tests/test-pixel-uninstall.sh
+          python3 tests/test_gpu_env_precedence.py
           python3 tests/contracts/test-network-exposure-contracts.py
           python3 tests/contracts/test-remote-provider-egress-policy.py
           python3 tests/contracts/test-remote-provider-egress-service.py

ods/extensions/services/dashboard-api/gpu.py

@@ -549,13 +549,22 @@ def _read_env_var_from_file_state(key: str) -> tuple[bool, str]:
     """Read a live .env value while preserving present-but-empty assignments."""
     install_dir = os.environ.get("ODS_INSTALL_DIR", os.path.expanduser("~/ods"))
     env_path = Path(install_dir) / ".env"
+    found = False
+    result = ""
+    prefix = f"{key}="
+    export_prefix = f"export {key}="
     try:
-        for line in env_path.read_text().splitlines():
-            if line.startswith(f"{key}="):
-                return True, parse_env_value(line[len(key) + 1:])
-    except OSError:
+        for raw in env_path.read_text(encoding="utf-8", errors="replace").splitlines():
+            line = raw.strip()
+            if line.startswith(prefix):
+                found = True
+                result = parse_env_value(line[len(prefix):])
+            elif line.startswith(export_prefix):
+                found = True
+                result = parse_env_value(line[len(export_prefix):])
+    except (OSError, UnicodeError):
         pass
-    return False, ""
+    return found, result
 
 
 def _read_env_var_from_file(key: str) -> str:

ods/tests/test_gpu_env_precedence.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+"""Regression test: gpu module env reader respects dotenv override precedence and export prefix."""
+
+from __future__ import annotations
+
+import os
+import sys
+import tempfile
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(ROOT / "extensions" / "services" / "dashboard-api"))
+
+import gpu  # noqa: E402
+
+
+def test_gpu_read_env_var_precedence_and_export():
+    with tempfile.TemporaryDirectory() as tmpdir:
+        tmp_path = Path(tmpdir)
+        env_file = tmp_path / ".env"
+
+        # Baseline: initial assignment overridden by later assignment; second var uses export prefix
+        env_file.write_text(
+            """
+# Default configuration
+GPU_BACKEND=cpu
+# Custom override appended by installer or operator
+GPU_BACKEND=nvidia
+export GPU_ACCELERATOR=cuda
+UNTOUCHED_VAR=kept
+# Non-ASCII UTF-8 comment: 🚀
+""",
+            encoding="utf-8",
+        )
+
+        old_dir = os.environ.get("ODS_INSTALL_DIR")
+        os.environ["ODS_INSTALL_DIR"] = str(tmp_path)
+        try:
+            # 1. Precedence: final assignment must override initial assignment
+            found, backend = gpu._read_env_var_from_file_state("GPU_BACKEND")
+            assert found is True
+            assert backend == "nvidia", f"Expected 'nvidia', got {backend!r}"
+
+            # 2. Export prefix: must parse key assigned with export prefix
+            found_acc, acc = gpu._read_env_var_from_file_state("GPU_ACCELERATOR")
+            assert found_acc is True
+            assert acc == "cuda", f"Expected 'cuda', got {acc!r}"
+
+            # 3. Missing key falls back cleanly to found=False
+            found_missing, missing = gpu._read_env_var_from_file_state("NON_EXISTENT")
+            assert found_missing is False
+            assert missing == ""
+        finally:
+            if old_dir is None:
+                os.environ.pop("ODS_INSTALL_DIR", None)
+            else:
+                os.environ["ODS_INSTALL_DIR"] = old_dir
+
+
+if __name__ == "__main__":
+    test_gpu_read_env_var_precedence_and_export()
+    print("test_gpu_env_precedence: OK")