Added errors.Cause() (#6)

mailgun · Jun 30, 2023 · 38abe5b · 38abe5b
1 parent 97c51d8
commit 38abe5b
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Showing 4 changed files with 21 additions and 6 deletions.
diff --git a/go.mod b/go.mod
@@ -4,14 +4,12 @@ go 1.19
 
 require (
 	github.com/ahmetb/go-linq v3.0.0+incompatible
-	github.com/mailgun/holster/v4 v4.11.0
 	github.com/sirupsen/logrus v1.9.0
 	github.com/stretchr/testify v1.8.1
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	golang.org/x/sys v0.0.0-20220919091848-fb04ddd9f9c8 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

diff --git a/go.sum b/go.sum
@@ -3,10 +3,6 @@ github.com/ahmetb/go-linq v3.0.0+incompatible/go.mod h1:PFffvbdbtw+QTB0WKRP0cNht
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/mailgun/holster/v4 v4.11.0 h1:c9DT3QZCfiUgcmOYvxJI9rRhLbtX6IqfaClrMjLxkLE=
-github.com/mailgun/holster/v4 v4.11.0/go.mod h1:sXpF+rzEqA89uBEiX19FrVUdbCUKDfR4GRdXmIkINQQ=
-github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
-github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/sirupsen/logrus v1.9.0 h1:trlNQbNUG3OdDrDil03MCb1H2o9nJ1x4/5LYw7byDE0=

diff --git a/wrap.go b/wrap.go
@@ -1,6 +1,7 @@
 package errors
 
 import (
+	"errors"
 	"fmt"
 	"io"
 
@@ -31,6 +32,17 @@ func Wrapf(err error, format string, a ...any) error {
 	}
 }
 
+// Cause returns the last error in the stack of wrapped errors.
+func Cause(err error) error {
+	for {
+		wrapped := errors.Unwrap(err)
+		if wrapped == nil {
+			return err
+		}
+		err = wrapped
+	}
+}
+
 type wrappedError struct {
 	msg     string
 	wrapped error

diff --git a/wrap_test.go b/wrap_test.go
@@ -124,3 +124,12 @@ func TestWrapErrorValue(t *testing.T) {
 	wrap := errors.Wrap(err, "message")
 	assert.True(t, errors.Is(wrap, io.EOF))
 }
+
+func TestCause(t *testing.T) {
+	err := errors.Errorf("error: %w", errors.Wrap(errors.Wrap(errors.New("the cause"), "wrap 2"), "wrap 1"))
+	cause := errors.Cause(err)
+	require.Error(t, err)
+	require.Error(t, cause)
+	assert.Equal(t, "error: wrap 1: wrap 2: the cause", err.Error())
+	assert.Equal(t, "the cause", cause.Error())
+}