feat: add errors.Is support to all errors

internal/encoding/error_test.go

@@ -0,0 +1,17 @@
+package encoding
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_encodingError(t *testing.T) {
+	err1 := fmt.Errorf("test error")
+	err2 := encodingError("encoding error")
+	assert.NotErrorIs(t, err1, err2)
+	assert.NotErrorIs(t, err2, err1)
+	assert.ErrorIs(t, err2, encodingError("encoding error"))
+	assert.NotErrorIs(t, err2, encodingError("other encodingerror"))
+}

util.go

@@ -37,6 +37,12 @@ func (pe ConfigParseError) Unwrap() error {
 	return pe.err
 }
 
+// Is adds a check to see if the specified target is an error of this type, see [errors.Is]
+func (pe ConfigParseError) Is(err error) bool {
+	_, ok := err.(*ConfigParseError)
+	return ok
+}
+
 // toCaseInsensitiveValue checks if the value is a  map;
 // if so, create a copy and lower-case the keys recursively.
 func toCaseInsensitiveValue(value any) any {

util_test.go

@@ -11,6 +11,7 @@
 package viper
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
@@ -84,3 +85,13 @@ func TestAbsPathify(t *testing.T) {
 		assert.Equal(t, test.output, got)
 	}
 }
+
+func TestConfigParseError(t *testing.T) {
+	// test a generic error
+	err1 := fmt.Errorf("test error")
+	assert.NotErrorIs(t, err1, &ConfigParseError{})
+	// test the wrapped generic error
+	err2 := ConfigParseError{err: err1}
+	assert.ErrorIs(t, err2, &ConfigParseError{})
+	assert.ErrorIs(t, err2.Unwrap(), err1)
+}

viper.go

@@ -61,6 +61,17 @@ func (e ConfigMarshalError) Error() string {
 	return fmt.Sprintf("While marshaling config: %s", e.err.Error())
 }
 
+// Unwrap returns the wrapped error.
+func (e ConfigMarshalError) Unwrap() error {
+	return e.err
+}
+
+// Is adds a check to see if the specified target is an error of this type, see [errors.Is]
+func (e ConfigMarshalError) Is(err error) bool {
+	_, ok := err.(*ConfigMarshalError)
+	return ok
+}
+
 var v *Viper
 
 type RemoteResponse struct {
@@ -118,6 +129,12 @@ func (fnfe ConfigFileNotFoundError) Error() string {
 	return fmt.Sprintf("Config File %q Not Found in %q", fnfe.name, fnfe.locations)
 }
 
+// Is adds a check to see if the specified target is an error of this type, see [errors.Is]
+func (e ConfigFileNotFoundError) Is(err error) bool {
+	_, ok := err.(*ConfigFileNotFoundError)
+	return ok
+}
+
 // ConfigFileAlreadyExistsError denotes failure to write new configuration file.
 type ConfigFileAlreadyExistsError string
 

viper_test.go

@@ -8,6 +8,7 @@ package viper
 import (
 	"bytes"
 	"encoding/json"
+	"fmt"
 	"io"
 	"os"
 	"os/exec"
@@ -2696,3 +2697,60 @@ func skipWindows(t *testing.T) {
 		t.Skip("Skip test on Windows")
 	}
 }
+
+// Test the ConfigMarshalError
+func TestConfigMarshalError(t *testing.T) {
+	// test a generic error
+	err1 := fmt.Errorf("test error")
+	assert.NotErrorIs(t, err1, &ConfigMarshalError{})
+	// test the wrapped generic error
+	err2 := ConfigMarshalError{err: err1}
+	assert.ErrorIs(t, err2, &ConfigMarshalError{})
+	assert.ErrorIs(t, err2.Unwrap(), err1)
+}
+
+func TestUnsupportedConfigError(t *testing.T) {
+	err1 := fmt.Errorf("test error")
+	err2 := UnsupportedConfigError("some string")
+	assert.NotErrorIs(t, err2, err1)
+	assert.NotErrorIs(t, err1, err2)
+	assert.ErrorIs(t, err2, UnsupportedConfigError("some string"))
+	assert.NotErrorIs(t, err2, UnsupportedConfigError("other string"))
+}
+
+func TestUnsupportedRemoteProviderError(t *testing.T) {
+	err1 := fmt.Errorf("test error")
+	err2 := UnsupportedRemoteProviderError("some string")
+	assert.NotErrorIs(t, err1, err2)
+	assert.NotErrorIs(t, err2, err1)
+	assert.ErrorIs(t, err2, UnsupportedRemoteProviderError("some string"))
+	assert.NotErrorIs(t, err2, UnsupportedRemoteProviderError("other string"))
+}
+
+func TestRemoteConfigError(t *testing.T) {
+	err1 := fmt.Errorf("test error")
+	err2 := RemoteConfigError("some string")
+	assert.NotErrorIs(t, err1, err2)
+	assert.NotErrorIs(t, err2, err1)
+	assert.ErrorIs(t, err2, RemoteConfigError("some string"))
+	assert.NotErrorIs(t, err2, RemoteConfigError("other string"))
+}
+
+func TestConfigFileNotFoundError(t *testing.T) {
+	err1 := fmt.Errorf("test error")
+	err2 := ConfigFileNotFoundError{name: "name", locations: "locations"}
+	assert.NotErrorIs(t, err1, err2)
+	assert.NotErrorIs(t, err2, err1)
+	assert.ErrorIs(t, err2, &ConfigFileNotFoundError{})
+	assert.ErrorIs(t, err2, &ConfigFileNotFoundError{name: "name", locations: "locations"})
+	assert.ErrorIs(t, err2, &ConfigFileNotFoundError{name: "other name", locations: "other locations"})
+}
+
+func TestConfigFileAlreadyExistsError(t *testing.T) {
+	err1 := fmt.Errorf("test error")
+	err2 := ConfigFileAlreadyExistsError("some string")
+	assert.NotErrorIs(t, err1, err2)
+	assert.NotErrorIs(t, err2, err1)
+	assert.ErrorIs(t, err2, ConfigFileAlreadyExistsError("some string"))
+	assert.NotErrorIs(t, err2, ConfigFileAlreadyExistsError("other string"))
+}