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Cleanup errors to help understand what failed. Fixes #75
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@evanphx
evanphx committed Jun 10, 2019
1 parent aad5688 commit 026c730
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Showing 2 changed files with 80 additions and 46 deletions.
124 changes: 79 additions & 45 deletions patch.go
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Expand Up @@ -3,10 +3,11 @@ package jsonpatch
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"strconv"
"strings"

"github.com/pkg/errors"
)

const (
Expand All @@ -25,6 +26,14 @@ var (
AccumulatedCopySizeLimit int64 = 0
)

var (
ErrTestFailed = errors.New("test failed")
ErrMissing = errors.New("missing value")
ErrUnknownType = errors.New("unknown object type")
ErrInvalid = errors.New("invalid state detected")
ErrInvalidIndex = errors.New("invalid index referenced")
)

type lazyNode struct {
raw *json.RawMessage
doc partialDoc
Expand Down Expand Up @@ -61,7 +70,7 @@ func (n *lazyNode) MarshalJSON() ([]byte, error) {
case eAry:
return json.Marshal(n.ary)
default:
return nil, fmt.Errorf("Unknown type")
return nil, ErrUnknownType
}
}

Expand Down Expand Up @@ -93,7 +102,7 @@ func (n *lazyNode) intoDoc() (*partialDoc, error) {
}

if n.raw == nil {
return nil, fmt.Errorf("Unable to unmarshal nil pointer as partial document")
return nil, ErrInvalid
}

err := json.Unmarshal(*n.raw, &n.doc)
Expand All @@ -112,7 +121,7 @@ func (n *lazyNode) intoAry() (*partialArray, error) {
}

if n.raw == nil {
return nil, fmt.Errorf("Unable to unmarshal nil pointer as partial array")
return nil, ErrInvalid
}

err := json.Unmarshal(*n.raw, &n.ary)
Expand Down Expand Up @@ -260,7 +269,7 @@ func (o Operation) Path() (string, error) {
return op, nil
}

return "unknown", errors.New("operation missing path field")
return "unknown", errors.Wrapf(ErrMissing, "operation missing path field")
}

// From reads the "from" field of the Operation.
Expand All @@ -277,7 +286,7 @@ func (o Operation) From() (string, error) {
return op, nil
}

return "unknown", errors.New("operation missing from field")
return "unknown", errors.Wrapf(ErrMissing, "operation, missing from field")
}

func (o Operation) value() *lazyNode {
Expand All @@ -302,7 +311,7 @@ func (o Operation) ValueInterface() (interface{}, error) {
return v, nil
}

return nil, errors.New("operation missing value field")
return nil, errors.Wrapf(ErrMissing, "operation, missing value field")
}

func isArray(buf []byte) bool {
Expand Down Expand Up @@ -381,7 +390,7 @@ func (d *partialDoc) get(key string) (*lazyNode, error) {
func (d *partialDoc) remove(key string) error {
_, ok := (*d)[key]
if !ok {
return fmt.Errorf("Unable to remove nonexistent key: %s", key)
return errors.Wrapf(ErrMissing, "Unable to remove nonexistent key: %s", key)
}

delete(*d, key)
Expand All @@ -407,7 +416,7 @@ func (d *partialArray) add(key string, val *lazyNode) error {

idx, err := strconv.Atoi(key)
if err != nil {
return err
return errors.Wrapf(err, "value was not a proper array index: '%s'", key)
}

sz := len(*d) + 1
Expand All @@ -417,12 +426,12 @@ func (d *partialArray) add(key string, val *lazyNode) error {
cur := *d

if idx >= len(ary) {
return fmt.Errorf("Unable to access invalid index: %d", idx)
return errors.Wrapf(ErrInvalidIndex, "Unable to access invalid index: %d", idx)
}

if SupportNegativeIndices {
if idx < -len(ary) {
return fmt.Errorf("Unable to access invalid index: %d", idx)
return errors.Wrapf(ErrInvalidIndex, "Unable to access invalid index: %d", idx)
}

if idx < 0 {
Expand All @@ -446,7 +455,7 @@ func (d *partialArray) get(key string) (*lazyNode, error) {
}

if idx >= len(*d) {
return nil, fmt.Errorf("Unable to access invalid index: %d", idx)
return nil, errors.Wrapf(ErrInvalidIndex, "Unable to access invalid index: %d", idx)
}

return (*d)[idx], nil
Expand All @@ -461,12 +470,12 @@ func (d *partialArray) remove(key string) error {
cur := *d

if idx >= len(cur) {
return fmt.Errorf("Unable to access invalid index: %d", idx)
return errors.Wrapf(ErrInvalidIndex, "Unable to access invalid index: %d", idx)
}

if SupportNegativeIndices {
if idx < -len(cur) {
return fmt.Errorf("Unable to access invalid index: %d", idx)
return errors.Wrapf(ErrInvalidIndex, "Unable to access invalid index: %d", idx)
}

if idx < 0 {
Expand All @@ -487,161 +496,186 @@ func (d *partialArray) remove(key string) error {
func (p Patch) add(doc *container, op Operation) error {
path, err := op.Path()
if err != nil {
return fmt.Errorf("jsonpatch add operation failed to decode path: %s", err)
return errors.Wrapf(ErrMissing, "add operation failed to decode path")
}

con, key := findObject(doc, path)

if con == nil {
return fmt.Errorf("jsonpatch add operation does not apply: doc is missing path: \"%s\"", path)
return errors.Wrapf(ErrMissing, "add operation does not apply: doc is missing path: \"%s\"", path)
}

return con.add(key, op.value())
err = con.add(key, op.value())
if err != nil {
return errors.Wrapf(err, "error in add for path: '%s'", path)
}

return nil
}

func (p Patch) remove(doc *container, op Operation) error {
path, err := op.Path()
if err != nil {
return fmt.Errorf("jsonpatch remove operation failed to decode path: %s", err)
return errors.Wrapf(ErrMissing, "remove operation failed to decode path")
}

con, key := findObject(doc, path)

if con == nil {
return fmt.Errorf("jsonpatch remove operation does not apply: doc is missing path: \"%s\"", path)
return errors.Wrapf(ErrMissing, "remove operation does not apply: doc is missing path: \"%s\"", path)
}

return con.remove(key)
err = con.remove(key)
if err != nil {
return errors.Wrapf(err, "error in remove for path: '%s'", path)
}

return nil
}

func (p Patch) replace(doc *container, op Operation) error {
path, err := op.Path()
if err != nil {
return fmt.Errorf("jsonpatch replace operation failed to decode path: %s", err)
return errors.Wrapf(err, "replace operation failed to decode path")
}

con, key := findObject(doc, path)

if con == nil {
return fmt.Errorf("jsonpatch replace operation does not apply: doc is missing path: %s", path)
return errors.Wrapf(ErrMissing, "replace operation does not apply: doc is missing path: %s", path)
}

_, ok := con.get(key)
if ok != nil {
return fmt.Errorf("jsonpatch replace operation does not apply: doc is missing key: %s", path)
return errors.Wrapf(ErrMissing, "replace operation does not apply: doc is missing key: %s", path)
}

err = con.set(key, op.value())
if err != nil {
return errors.Wrapf(err, "error in remove for path: '%s'", path)
}

return con.set(key, op.value())
return nil
}

func (p Patch) move(doc *container, op Operation) error {
from, err := op.From()
if err != nil {
return fmt.Errorf("jsonpatch move operation failed to decode from: %s", err)
return errors.Wrapf(err, "move operation failed to decode from")
}

con, key := findObject(doc, from)

if con == nil {
return fmt.Errorf("jsonpatch move operation does not apply: doc is missing from path: %s", from)
return errors.Wrapf(ErrMissing, "move operation does not apply: doc is missing from path: %s", from)
}

val, err := con.get(key)
if err != nil {
return err
return errors.Wrapf(err, "error in move for path: '%s'", key)
}

err = con.remove(key)
if err != nil {
return err
return errors.Wrapf(err, "error in move for path: '%s'", key)
}

path, err := op.Path()
if err != nil {
return fmt.Errorf("jsonpatch move operation failed to decode path: %s", err)
return errors.Wrapf(err, "move operation failed to decode path")
}

con, key = findObject(doc, path)

if con == nil {
return fmt.Errorf("jsonpatch move operation does not apply: doc is missing destination path: %s", path)
return errors.Wrapf(ErrMissing, "move operation does not apply: doc is missing destination path: %s", path)
}

err = con.add(key, val)
if err != nil {
return errors.Wrapf(err, "error in move for path: '%s'", path)
}

return con.add(key, val)
return nil
}

func (p Patch) test(doc *container, op Operation) error {
path, err := op.Path()
if err != nil {
return fmt.Errorf("jsonpatch test operation failed to decode path: %s", err)
return errors.Wrapf(err, "test operation failed to decode path")
}

con, key := findObject(doc, path)

if con == nil {
return fmt.Errorf("jsonpatch test operation does not apply: is missing path: %s", path)
return errors.Wrapf(ErrMissing, "test operation does not apply: is missing path: %s", path)
}

val, err := con.get(key)

if err != nil {
return err
return errors.Wrapf(err, "error in test for path: '%s'", path)
}

if val == nil {
if op.value().raw == nil {
return nil
}
return fmt.Errorf("Testing value %s failed", path)
return errors.Wrapf(ErrTestFailed, "testing value %s failed", path)
} else if op.value() == nil {
return fmt.Errorf("Testing value %s failed", path)
return errors.Wrapf(ErrTestFailed, "testing value %s failed", path)
}

if val.equal(op.value()) {
return nil
}

return fmt.Errorf("Testing value %s failed", path)
return errors.Wrapf(ErrTestFailed, "testing value %s failed", path)
}

func (p Patch) copy(doc *container, op Operation, accumulatedCopySize *int64) error {
from, err := op.From()
if err != nil {
return fmt.Errorf("jsonpatch copy operation failed to decode from: %s", err)
return errors.Wrapf(err, "copy operation failed to decode from")
}

con, key := findObject(doc, from)

if con == nil {
return fmt.Errorf("jsonpatch copy operation does not apply: doc is missing from path: %s", from)
return errors.Wrapf(ErrMissing, "copy operation does not apply: doc is missing from path: %s", from)
}

val, err := con.get(key)
if err != nil {
return err
return errors.Wrapf(err, "error in copy for from: '%s'", from)
}

path, err := op.Path()
if err != nil {
return fmt.Errorf("jsonpatch copy operation failed to decode path: %s", err)
return errors.Wrapf(ErrMissing, "copy operation failed to decode path")
}

con, key = findObject(doc, path)

if con == nil {
return fmt.Errorf("jsonpatch copy operation does not apply: doc is missing destination path: %s", path)
return errors.Wrapf(ErrMissing, "copy operation does not apply: doc is missing destination path: %s", path)
}

valCopy, sz, err := deepCopy(val)
if err != nil {
return err
return errors.Wrapf(err, "error while performing deep copy")
}

(*accumulatedCopySize) += int64(sz)
if AccumulatedCopySizeLimit > 0 && *accumulatedCopySize > AccumulatedCopySizeLimit {
return NewAccumulatedCopySizeError(AccumulatedCopySizeLimit, *accumulatedCopySize)
}

return con.add(key, valCopy)
err = con.add(key, valCopy)
if err != nil {
return errors.Wrapf(err, "error while adding value during copy")
}

return nil
}

// Equal indicates if 2 JSON documents have the same structural equality.
Expand Down
2 changes: 1 addition & 1 deletion patch_test.go
View file
Expand Up @@ -470,7 +470,7 @@ func TestAllTest(t *testing.T) {
} else if !c.result && err == nil {
t.Errorf("Testing passed when it should have faild: %s", err)
} else if !c.result {
expected := fmt.Sprintf("Testing value %s failed", c.failedPath)
expected := fmt.Sprintf("testing value %s failed: test failed", c.failedPath)
if err.Error() != expected {
t.Errorf("Testing failed as expected but invalid message: expected [%s], got [%s]", expected, err)
}
Expand Down

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