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Preventing panics of RecoverableError casts #2267

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merged 4 commits into from
Feb 1, 2017
Merged

Preventing panics of RecoverableError casts #2267

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09ba15f
Preventing panics of RecoverableError casts
Feb 1, 2017
5326ad3
Properly dealing with non-nil errors.
Feb 1, 2017
57c9ff3
Third time is a charm.
Feb 1, 2017
e887e80
fmt
Feb 1, 2017
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4 changes: 2 additions & 2 deletions nomad/node_endpoint.go
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Original file line number Diff line number Diff line change
Expand Up @@ -944,7 +944,7 @@ func (n *Node) DeriveVaultToken(args *structs.DeriveVaultTokenRequest,
// setErr is a helper for setting the recoverable error on the reply and
// logging it
setErr := func(e error, recoverable bool) {
reply.Error = structs.NewRecoverableError(e, recoverable).(*structs.RecoverableError)
reply.Error = structs.NewRecoverableError(e, recoverable)
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Instead of omitting the type assertion, let's just check if error is nil and return early.

Otherwise we re-introduce a bug where reply.Error gets set even when the original error e was nil!

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I was going to do a type assertion before I thought I could just change the return type.
Will have shortly.

n.srv.logger.Printf("[ERR] nomad.client: DeriveVaultToken failed (recoverable %v): %v", recoverable, e)
}

Expand Down Expand Up @@ -1134,7 +1134,7 @@ func (n *Node) DeriveVaultToken(args *structs.DeriveVaultTokenRequest,
if rerr, ok := createErr.(*structs.RecoverableError); ok {
reply.Error = rerr
} else {
reply.Error = structs.NewRecoverableError(createErr, false).(*structs.RecoverableError)
reply.Error = structs.NewRecoverableError(createErr, false)
}

return nil
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2 changes: 1 addition & 1 deletion nomad/structs/structs.go
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Expand Up @@ -4054,7 +4054,7 @@ type RecoverableError struct {

// NewRecoverableError is used to wrap an error and mark it as recoverable or
// not.
func NewRecoverableError(e error, recoverable bool) error {
func NewRecoverableError(e error, recoverable bool) *RecoverableError {
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So, I changed this return value from *RecoverableError to error intentionally in 0.5.3 to avoid turning nil errors into non-nil *RecoverableErrors. Here's an example of that sort of problem: https://play.golang.org/p/Y8z9GdcAhx

So let's keep returning error here to avoid that issue.

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Thanks for the awesome explanation. What a nasty side effect.

if e == nil {
return nil
}
Expand Down