***Optimzation**: Never issue refresh event when Grafana tab is not visible [#7218](https://github.com/grafana/grafana/issues/7218), thx [@mtanda](https://github.com/mtanda)
***Browser History**: Browser back/forward now works time ranges / zoom, [#7259](https://github.com/grafana/grafana/issues/7259)
## Bugfixes
***Alerting**: Fixes missing support for no_data and execution error when testing alerts [#7149](https://github.com/grafana/grafana/issues/7149)
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null is a library with reasonable options for dealing with nullable SQL and JSON values
There are two packages: `null` and its subpackage `zero`.
Types in `null` will only be considered null on null input, and will JSON encode to `null`. If you need zero and null be considered separate values, use these.
Types in `zero` are treated like zero values in Go: blank string input will produce a null `zero.String`, and null Strings will JSON encode to `""`. Zero values of these types will be considered null to SQL. If you need zero and null treated the same, use these.
All types implement `sql.Scanner` and `driver.Valuer`, so you can use this library in place of `sql.NullXXX`. All types also implement: `encoding.TextMarshaler`, `encoding.TextUnmarshaler`, `json.Marshaler`, and `json.Unmarshaler`.
### null package
`import "gopkg.in/guregu/null.v3"`
#### null.String
Nullable string.
Marshals to JSON null if SQL source data is null. Zero (blank) input will not produce a null String. Can unmarshal from `sql.NullString` JSON input or string input.
#### null.Int
Nullable int64.
Marshals to JSON null if SQL source data is null. Zero input will not produce a null Int. Can unmarshal from `sql.NullInt64` JSON input.
#### null.Float
Nullable float64.
Marshals to JSON null if SQL source data is null. Zero input will not produce a null Float. Can unmarshal from `sql.NullFloat64` JSON input.
#### null.Bool
Nullable bool.
Marshals to JSON null if SQL source data is null. False input will not produce a null Bool. Can unmarshal from `sql.NullBool` JSON input.
#### null.Time
Marshals to JSON null if SQL source data is null. Uses `time.Time`'s marshaler. Can unmarshal from `pq.NullTime` and similar JSON input.
### zero package
`import "gopkg.in/guregu/null.v3/zero"`
#### zero.String
Nullable string.
Will marshal to a blank string if null. Blank string input produces a null String. Null values and zero values are considered equivalent. Can unmarshal from `sql.NullString` JSON input.
#### zero.Int
Nullable int64.
Will marshal to 0 if null. 0 produces a null Int. Null values and zero values are considered equivalent. Can unmarshal from `sql.NullInt64` JSON input.
#### zero.Float
Nullable float64.
Will marshal to 0 if null. 0.0 produces a null Float. Null values and zero values are considered equivalent. Can unmarshal from `sql.NullFloat64` JSON input.
#### zero.Bool
Nullable bool.
Will marshal to false if null. `false` produces a null Float. Null values and zero values are considered equivalent. Can unmarshal from `sql.NullBool` JSON input.
#### zero.Time
Will marshal to the zero time if null. Uses `time.Time`'s marshaler. Can unmarshal from `pq.NullTime` and similar JSON input.
### Bugs
`json`'s `",omitempty"` struct tag does not work correctly right now. It will never omit a null or empty String. This might be [fixed eventually](https://github.com/golang/go/issues/4357).
// Time is a nullable time.Time. It supports SQL and JSON serialization.
// It will marshal to null if null.
typeTimestruct{
Timetime.Time
Validbool
}
// Scan implements the Scanner interface.
func(t*Time)Scan(valueinterface{})error{
varerrerror
switchx:=value.(type){
casetime.Time:
t.Time=x
casenil:
t.Valid=false
returnnil
default:
err=fmt.Errorf("null: cannot scan type %T into null.Time: %v",value,value)
}
t.Valid=err==nil
returnerr
}
// Value implements the driver Valuer interface.
func(tTime)Value()(driver.Value,error){
if!t.Valid{
returnnil,nil
}
returnt.Time,nil
}
// NewTime creates a new Time.
funcNewTime(ttime.Time,validbool)Time{
returnTime{
Time:t,
Valid:valid,
}
}
// TimeFrom creates a new Time that will always be valid.
funcTimeFrom(ttime.Time)Time{
returnNewTime(t,true)
}
// TimeFromPtr creates a new Time that will be null if t is nil.
funcTimeFromPtr(t*time.Time)Time{
ift==nil{
returnNewTime(time.Time{},false)
}
returnNewTime(*t,true)
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this time is null.
func(tTime)MarshalJSON()([]byte,error){
if!t.Valid{
return[]byte("null"),nil
}
returnt.Time.MarshalJSON()
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports string, object (e.g. pq.NullTime and friends)
// and null input.
func(t*Time)UnmarshalJSON(data[]byte)error{
varerrerror
varvinterface{}
iferr=json.Unmarshal(data,&v);err!=nil{
returnerr
}
switchx:=v.(type){
casestring:
err=t.Time.UnmarshalJSON(data)
casemap[string]interface{}:
ti,tiOK:=x["Time"].(string)
valid,validOK:=x["Valid"].(bool)
if!tiOK||!validOK{
returnfmt.Errorf(`json: unmarshalling object into Go value of type null.Time requires key "Time" to be of type string and key "Valid" to be of type bool; found %T and %T, respectively`,x["Time"],x["Valid"])
}
err=t.Time.UnmarshalText([]byte(ti))
t.Valid=valid
returnerr
casenil:
t.Valid=false
returnnil
default:
err=fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Time",reflect.TypeOf(v).Name())
}
t.Valid=err==nil
returnerr
}
func(tTime)MarshalText()([]byte,error){
if!t.Valid{
return[]byte("null"),nil
}
returnt.Time.MarshalText()
}
func(t*Time)UnmarshalText(text[]byte)error{
str:=string(text)
ifstr==""||str=="null"{
t.Valid=false
returnnil
}
iferr:=t.Time.UnmarshalText(text);err!=nil{
returnerr
}
t.Valid=true
returnnil
}
// SetValid changes this Time's value and sets it to be non-null.
func(t*Time)SetValid(vtime.Time){
t.Time=v
t.Valid=true
}
// Ptr returns a pointer to this Time's value, or a nil pointer if this Time is null.
