Try: Simplified Error Handling in Go
This module reduces the syntactic cost of error handling in Go.
Example usage in a main program:
func main() {
defer try.F(log.Fatal)
b := try.E1(os.ReadFile(...))
var v any
try.E(json.Unmarshal(b, &v))
...
}Example usage in a unit test:
func Test(t *testing.T) {
defer try.F(t.Fatal)
db := try.E1(setdb.Open(...))
defer db.Close()
...
try.E(db.Commit())
}Code before try:
func (a *MixedArray) UnmarshalNext(uo json.UnmarshalOptions, d *json.Decoder) error {
switch t, err := d.ReadToken(); {
case err != nil:
return err
case t.Kind() != '[':
return fmt.Errorf("got %v, expecting array start", t.Kind())
}
if err := uo.UnmarshalNext(d, &a.Scalar); err != nil {
return err
}
if err := uo.UnmarshalNext(d, &a.Slice); err != nil {
return err
}
if err := uo.UnmarshalNext(d, &a.Map); err != nil {
return err
}
switch t, err := d.ReadToken(); {
case err != nil:
return err
case t.Kind() != ']':
return fmt.Errorf("got %v, expecting array end", t.Kind())
}
return nil
}Code after try:
func (a *MixedArray) UnmarshalNext(uo json.UnmarshalOptions, d *json.Decoder) (err error) {
defer try.Handle(&err)
if t := try.E1(d.ReadToken()); t.Kind() != '[' {
return fmt.Errorf("found %v, expecting array start", t.Kind())
}
try.E(uo.UnmarshalNext(d, &a.Scalar))
try.E(uo.UnmarshalNext(d, &a.Slice))
try.E(uo.UnmarshalNext(d, &a.Map))
if t := try.E1(d.ReadToken()); t.Kind() != ']' {
return fmt.Errorf("found %v, expecting array end", t.Kind())
}
return nil
}See the documentation for more information.
Install
go get -u github.com/dsnet/try
Semgrep rules
These semgrep rules can help prevent bugs and abuse:
rules:
- id: non-deferred-try-handle
patterns:
- pattern-either:
- pattern: try.F(...)
- pattern: try.Handle(...)
- pattern: try.HandleF(...)
- pattern: try.Recover(...)
- pattern-not: defer try.F(...)
- pattern-not: defer try.Handle(...)
- pattern-not: defer try.HandleF(...)
- pattern-not: defer try.Recover(...)
message: Calls to try handlers must be deferred
severity: ERROR
languages:
- go
- id: missing-try-handler
patterns:
- pattern-either:
- pattern: try.E(...)
- pattern: try.E1(...)
- pattern: try.E2(...)
- pattern: try.E3(...)
- pattern: try.E4(...)
- pattern-not-inside: |
...
defer try.F(...)
...
- pattern-not-inside: |
...
defer try.Handle(...)
...
- pattern-not-inside: |
...
defer try.HandleF(...)
...
- pattern-not-inside: |
...
defer try.Recover(...)
...
message: Calls to try.E[n] must have a matching function-local handler
severity: ERROR
languages:
- goLicense
BSD - See LICENSE file