merr: move With/GetValue to kv.go, make nil error behavior be explicitly defined and tested

This commit is contained in:
Brian Picciano 2019-01-24 16:45:38 -05:00
parent 0e80e1fd3d
commit 405120513f
4 changed files with 48 additions and 18 deletions

View File

@ -5,6 +5,32 @@ import (
"path/filepath"
)
// WithValue returns a copy of the original error, automatically wrapping it if
// the error is not from merr (see Wrap). The returned error has a value set on
// with for the given key.
//
// visible determines whether or not the value is visible in the output of
// Error.
func WithValue(e error, k, v interface{}, visible bool) error {
if e == nil {
return nil
}
er := wrap(e, true, 1)
er.attr[k] = val{val: v, visible: visible}
return er
}
// GetValue returns the value embedded in the error for the given key, or nil if
// the error isn't from this package or doesn't have that key embedded.
func GetValue(e error, k interface{}) interface{} {
if e == nil {
return nil
}
return wrap(e, false, -1).attr[k].val
}
////////////////////////////////////////////////////////////////////////////////
// not really used for attributes, but w/e
const attrKeyErr attrKey = "err"
const attrKeyErrSrc attrKey = "errSrc"
@ -27,6 +53,10 @@ func (kv KVer) KV() map[string]interface{} {
// If any keys conflict then their type information will be included as part of
// the key.
func KV(e error) KVer {
if e == nil {
return KVer{}
}
er := wrap(e, false, 1)
kvm := make(map[string]interface{}, len(er.attr)+1)

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@ -8,6 +8,13 @@ import (
)
func TestKV(t *T) {
massert.Fatal(t, massert.All(
massert.Nil(WithValue(nil, "foo", "bar", true)),
massert.Nil(WithValue(nil, "foo", "bar", false)),
massert.Nil(GetValue(nil, "foo")),
massert.Len(KV(nil).KV(), 0),
))
er := New("foo")
kv := KV(er).KV()
massert.Fatal(t, massert.Comment(

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@ -1,5 +1,11 @@
// Package merr extends the errors package with features like key-value
// attributes for errors, embedded stacktraces, and multi-errors.
//
// merr functions takes in generic errors of the built-in type. The returned
// errors are wrapped by a type internal to merr, and appear to also be of the
// generic error type. This means that equality checking will not work, unless
// the Base function is used. If any functions are given nil they will also
// return nil.
package merr
import (
@ -39,6 +45,10 @@ type err struct {
type attrKey string
func wrap(e error, cp bool, skip int) *err {
if e == nil {
return nil
}
er, ok := e.(*err)
if !ok {
er := &err{err: e, attr: map[interface{}]val{}}
@ -132,24 +142,6 @@ func (er *err) Error() string {
return sb.String()
}
// WithValue returns a copy of the original error, automatically wrapping it if
// the error is not from merr (see Wrap). The returned error has a value set on
// with for the given key.
//
// visible determines whether or not the value is visible in the output of
// Error.
func WithValue(e error, k, v interface{}, visible bool) error {
er := wrap(e, true, 1)
er.attr[k] = val{val: v, visible: visible}
return er
}
// GetValue returns the value embedded in the error for the given key, or nil if
// the error isn't from this package or doesn't have that key embedded.
func GetValue(e error, k interface{}) interface{} {
return wrap(e, false, -1).attr[k].val
}
// Base takes in an error and checks if it is merr's internal error type. If it
// is then the underlying error which is being wrapped is returned. If it's not
// then the passed in error is returned as-is.

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@ -31,6 +31,7 @@ func TestBase(t *T) {
errFoo, errBar := errors.New("foo"), errors.New("bar")
erFoo := Wrap(errFoo)
massert.Fatal(t, massert.All(
massert.Nil(Base(nil)),
massert.Equal(errFoo, Base(erFoo)),
massert.Equal(errBar, Base(errBar)),
massert.Not(massert.Equal(errFoo, erFoo)),