runtime: read_only local sources become :ro bind mounts

A local_code target can mark its tree read_only; collect_local_sources
forwards the flag and build_bind_mounts mounts the tree read-only instead
of relying on host mode bits, skipping the per-metadata remounts since the
whole tree is already immutable. Used for pulled container image layouts.

strix/interface/utils.py

@@ -1323,6 +1323,7 @@ def collect_local_sources(targets_info: list[dict[str, Any]]) -> list[dict[str,
                     "source_path": details["target_path"],
                     "workspace_subdir": workspace_subdir,
                     "protect_metadata": True,
+                    "read_only": bool(details.get("read_only")),
                 }
             )
 

strix/runtime/session_manager.py

@@ -70,8 +70,9 @@ def build_bind_mounts(local_sources: list[dict[str, Any]]) -> list[dict[str, Any
             continue
         resolved = Path(host_path).expanduser().resolve()
         target = f"{_WORKSPACE_ROOT}/{ws_subdir}"
-        bind_mounts.append({"source": str(resolved), "target": target, "read_only": False})
-        if src.get("protect_metadata"):
+        read_only = bool(src.get("read_only"))
+        bind_mounts.append({"source": str(resolved), "target": target, "read_only": read_only})
+        if src.get("protect_metadata") and not read_only:
             bind_mounts.extend(_metadata_mounts(resolved, target))
     return bind_mounts
 

tests/test_local_sources.py

@@ -30,7 +30,26 @@ def _local_target(target_path: str) -> dict[str, Any]:
 def test_collect_local_sources_protects_the_users_own_git() -> None:
     sources = collect_local_sources([_local_target("/code")])
     assert sources == [
-        {"source_path": "/code", "workspace_subdir": "repo", "protect_metadata": True}
+        {
+            "source_path": "/code",
+            "workspace_subdir": "repo",
+            "protect_metadata": True,
+            "read_only": False,
+        }
+    ]
+
+
+def test_collect_local_sources_forwards_read_only() -> None:
+    target = _local_target("/layout")
+    target["details"]["read_only"] = True
+    sources = collect_local_sources([target])
+    assert sources == [
+        {
+            "source_path": "/layout",
+            "workspace_subdir": "repo",
+            "protect_metadata": True,
+            "read_only": True,
+        }
     ]
 
 

tests/test_session_entries.py

@@ -27,8 +27,15 @@ from strix.runtime.session_manager import (
 )
 
 
-def _source(subdir: str, path: str, *, protect_metadata: bool = False) -> dict[str, Any]:
-    return {"source_path": path, "workspace_subdir": subdir, "protect_metadata": protect_metadata}
+def _source(
+    subdir: str, path: str, *, protect_metadata: bool = False, read_only: bool = False
+) -> dict[str, Any]:
+    return {
+        "source_path": path,
+        "workspace_subdir": subdir,
+        "protect_metadata": protect_metadata,
+        "read_only": read_only,
+    }
 
 
 def test_source_becomes_writable_bind_mount(tmp_path: Path) -> None:
@@ -124,6 +131,16 @@ def test_clone_keeps_its_git_writable(tmp_path: Path) -> None:
     assert [m["target"] for m in mounts] == ["/workspace/clone"]
 
 
+def test_read_only_source_is_one_read_only_mount(tmp_path: Path) -> None:
+    (tmp_path / ".git").mkdir()
+    mounts = build_bind_mounts(
+        [_source("image", str(tmp_path), protect_metadata=True, read_only=True)]
+    )
+    assert mounts == [
+        {"source": str(tmp_path.resolve()), "target": "/workspace/image", "read_only": True}
+    ]
+
+
 def test_multiple_sources_each_get_a_mount(tmp_path: Path) -> None:
     first = tmp_path / "first"
     second = tmp_path / "second"