fix(docker): surface enumeration failures

bot_bottle/backend/docker/compose.py

@@ -52,19 +52,20 @@ def slug_from_compose_project(project: str) -> str:
 
 
 def list_compose_projects(
-    *, include_stopped: bool = True, warn_on_error: bool = True,
+    *,
+    include_stopped: bool = True,
+    warn_on_error: bool = True,
+    raise_on_error: bool = False,
 ) -> list[str]:
     """All compose project names starting with `bot-bottle-`.
     `include_stopped=True` (default) runs `docker compose ls --all`
     so exited projects appear too; pass False to get only projects
     with at least one running container.
 
-    Returns [] on docker daemon errors or malformed output rather
-    than raising — callers should treat the empty list as "no
-    projects discoverable", not "no projects exist". `warn_on_error`
-    stays true for explicit operator commands like cleanup, but active
-    discovery paths set it false so dashboard refreshes don't spam
-    stderr while Docker Desktop is stopped."""
+    Best-effort callers get ``[]`` on Docker errors or malformed output.
+    Enumeration callers pass ``raise_on_error=True`` so a failed query is not
+    reported as an authoritative empty result.
+    """
     argv = ["docker", "compose", "ls", "--format", "json"]
     if include_stopped:
         argv.insert(3, "--all")
@@ -72,19 +73,25 @@ def list_compose_projects(
         result = subprocess.run(
             argv, capture_output=True, text=True, check=False,
         )
-    except FileNotFoundError:
-        # docker binary not on PATH — same shape as a daemon-down
-        # error from the caller's POV: no projects discoverable.
+    except FileNotFoundError as exc:
+        if raise_on_error:
+            raise RuntimeError("docker compose ls failed: docker not found") from exc
         return []
     if result.returncode != 0:
+        message = f"docker compose ls failed: {result.stderr.strip()}"
+        if raise_on_error:
+            raise RuntimeError(message)
         if warn_on_error:
-            warn(f"docker compose ls failed: {result.stderr.strip()}")
+            warn(message)
         return []
     try:
         projects = json.loads(result.stdout or "[]")
     except json.JSONDecodeError as e:
+        message = f"docker compose ls returned malformed JSON: {e}"
+        if raise_on_error:
+            raise RuntimeError(message) from e
         if warn_on_error:
-            warn(f"docker compose ls returned malformed JSON: {e}")
+            warn(message)
         return []
     names: list[str] = []
     for p in projects:
@@ -97,7 +104,10 @@ def list_compose_projects(
 
 
 def list_active_slugs(
-    *, include_stopped: bool = False, warn_on_error: bool = True,
+    *,
+    include_stopped: bool = False,
+    warn_on_error: bool = True,
+    raise_on_error: bool = False,
 ) -> list[str]:
     """Slugs (project name minus prefix) of currently-running
     bottles. Used by the dashboard's operator-edit verbs to choose
@@ -108,6 +118,7 @@ def list_active_slugs(
             for p in list_compose_projects(
                 include_stopped=include_stopped,
                 warn_on_error=warn_on_error,
+                raise_on_error=raise_on_error,
             )
         ) if slug
     )