o/configstate, o/snapshotstate: fix handling of nil snap config on snapshot restore #10007
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Needs Samuele review
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| @@ -145,7 +145,8 @@ func GetSnapConfig(st *state.State, snapName string) (*json.RawMessage, error) { | |||
| func SetSnapConfig(st *state.State, snapName string, snapcfg *json.RawMessage) error { | |||
| var config map[string]*json.RawMessage | |||
| err := st.Get("config", &config) | |||
| isNil := snapcfg == nil || len(*snapcfg) == 0 | |||
| // empty nil snapcfg should be an empty message, but deal with "null" as well. | |||
| isNil := snapcfg == nil || len(*snapcfg) == 0 || bytes.Compare(*snapcfg, []byte("null")) == 0 | |||
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If I remove the "bytes.Compare()" here and run the (unit and snapshot-basic spread) tests nothing changes:
index 737421270d..563c5c49ae 100644
--- a/overlord/configstate/config/helpers.go
+++ b/overlord/configstate/config/helpers.go
@@ -146,7 +146,7 @@ func SetSnapConfig(st *state.State, snapName string, snapcfg *json.RawMessage) e
var config map[string]*json.RawMessage
err := st.Get("config", &config)
// empty nil snapcfg should be an empty message, but deal with "null" as well.
- isNil := snapcfg == nil || len(*snapcfg) == 0 || bytes.Compare(*snapcfg, []byte("null")) == 0
+ isNil := snapcfg == nil || len(*snapcfg) == 0
if err == state.ErrNoState {
if isNil {
// bail out early
so either:
a) I did something wrong
b) this is not needed
c) our tests need to improve
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Great catch! The check in the test was not sufficient, added now. Thanks!
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Fix for LP #1917870. The root cause is that if snapshot.Conf is nil and is marshaled into json.RawMessage, the later check if serialized value is nil or has len==0 is not working, because json.RawMessage is literally "null". So we put null as the root config of the given snap, and this later explodes in Commit on snap set ..., because we're not expecting nil maps at this level.
The fix avoids marshaling of nil config, but as an extra measure SetSnapConfig() also deals with "null" raw message.