T7957: filter stderr when deleting container images

The call to rc_cmd('podman inspect ...') determines whether a container image
scheduled for deletion has any ancestor containers still using it. Previously,
if the podman command wrote output to stderr, rc_cmd() would return that error
message alongside or instead of the ancestor container ID.

This caused subsequent podman calls to fail, as the error string was incorrectly
treated as a valid command argument. This change ensures only valid ancestor
IDs are returned.

This is a fix for commit a99ca6d11b5 ("op-mode: T7403: add option for forcefully
remove a container image")

1 files changed, 2 insertions, 2 deletions

diff --git a/src/op_mode/container.py b/src/op_mode/container.py
index 3dd665051..a34901cb4 100755
--- a/src/op_mode/container.py
+++ b/src/op_mode/container.py
@@ -120,11 +120,11 @@ def delete_image(name: str, force: typing.Optional[bool] = False):
 
     for image in name:
         # convert the truncated image ID to a full image ID
-        rc, ancestor = rc_cmd(f'podman inspect {image} --format "{{{{.Id}}}}"')
+        rc, ancestor = rc_cmd(f'podman inspect {image} --format "{{{{.Id}}}}"', stderr=None)
         if rc != 0:
             raise vyos.opmode.InternalError(ancestor)
         # check if the image ID is an ancestor of any running container
-        rc, in_use = rc_cmd(f'podman ps --filter ancestor={ancestor} -q')
+        rc, in_use = rc_cmd(f'podman ps --filter ancestor={ancestor} -q', stderr=None)
         if rc != 0:
             raise vyos.opmode.InternalError(in_use)