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evalengine: Fix JSON Path support for same-value ranges. #19020

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evalengine: Fix JSON Path support for same-value ranges. #19020

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364e8e3
Add a failing test case for single-element ranges.
arthurschreiber Dec 12, 2025
b5d4474
Add more failing test cases.
arthurschreiber Dec 12, 2025
d8a08a9
Fix single index range parsing.
arthurschreiber Dec 12, 2025
ff62f88
Fix single-value path range support.
arthurschreiber Dec 12, 2025
0f5f04a
Refactor test cases.
arthurschreiber Dec 12, 2025
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51 changes: 42 additions & 9 deletions go/mysql/json/json_path.go
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,7 @@ const (
jpMemberAny
jpArrayLocation
jpArrayLocationAny
jpArrayLocationRange
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@arthurschreiber arthurschreiber Dec 12, 2025

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I had to add a new json path kind here. Previously offset0 and offset1 were used to distinguish between an array offset and an array range, but this does not work for things like $[0 to 0] or $[last to last]. So I figured adding a separate kind is simpler and cleaner.

jpAny
)

Expand Down Expand Up @@ -71,6 +72,15 @@ func (jp *Path) format(b *strings.Builder) {
case jpMemberAny:
b.WriteString(".*")
case jpArrayLocation:
switch {
case jp.offset0 == -1:
b.WriteString("[last]")
case jp.offset0 >= 0:
_, _ = fmt.Fprintf(b, "[%d]", jp.offset0)
case jp.offset0 < 0:
_, _ = fmt.Fprintf(b, "[last%d]", jp.offset0+1)
}
case jpArrayLocationRange:
switch {
case jp.offset0 == -1:
b.WriteString("[last")
Expand All @@ -82,7 +92,7 @@ func (jp *Path) format(b *strings.Builder) {
switch {
case jp.offset1 == -1:
b.WriteString(" to last")
case jp.offset1 > 0:
case jp.offset1 >= 0:
_, _ = fmt.Fprintf(b, " to %d", jp.offset1)
case jp.offset1 < 0:
_, _ = fmt.Fprintf(b, " to last%d", jp.offset1+1)
Expand All @@ -107,12 +117,8 @@ func (jp *Path) String() string {
func (jp *Path) ContainsWildcards() bool {
for jp != nil {
switch jp.kind {
case jpAny, jpArrayLocationAny, jpMemberAny:
case jpAny, jpArrayLocationAny, jpArrayLocationRange, jpMemberAny:
return true
case jpArrayLocation:
if jp.offset1 != 0 {
return true
}
}
jp = jp.next
}
Expand Down Expand Up @@ -186,6 +192,15 @@ func (m *matcher) value(p *Path, v *Value) {
})
}
case jpArrayLocation:
if ary, ok := v.Array(); ok {
from, _ := p.arrayOffsets(ary)
if from >= 0 && from < len(ary) {
m.value(p.next, ary[from])
}
} else if m.wrap && (p.offset0 == 0 || p.offset0 == -1) {
m.value(p.next, v)
}
case jpArrayLocationRange:
if ary, ok := v.Array(); ok {
from, to := p.arrayOffsets(ary)
if from >= 0 && from < len(ary) {
Expand All @@ -196,7 +211,7 @@ func (m *matcher) value(p *Path, v *Value) {
m.value(p.next, ary[n])
}
}
} else if m.wrap && (p.offset0 == 0 || p.offset0 == -1) {
} else if m.wrap && (p.offset0 == 0 || p.offset1 == -1) {
m.value(p.next, v)
}
case jpArrayLocationAny:
Expand Down Expand Up @@ -233,6 +248,20 @@ func (jp *Path) transform(v *Value, t func(pp *Path, vv *Value)) {
jp.next.transform(obj.Get(jp.name), t)
}
case jpArrayLocation:
if ary, ok := v.Array(); ok {
from, _ := jp.arrayOffsets(ary)
if from >= 0 && from < len(ary) {
jp.next.transform(ary[from], t)
}
} else if jp.offset0 == 0 || jp.offset0 == -1 {
/*
If the path is evaluated against a value that is not an array,
the result of the evaluation is the same as if the value had been
wrapped in a single-element array:
*/
jp.next.transform(v, t)
}
case jpArrayLocationRange:
if ary, ok := v.Array(); ok {
from, to := jp.arrayOffsets(ary)
if from != to {
Expand All @@ -241,7 +270,7 @@ func (jp *Path) transform(v *Value, t func(pp *Path, vv *Value)) {
if from >= 0 && from < len(ary) {
jp.next.transform(ary[from], t)
}
} else if jp.offset0 == 0 || jp.offset0 == -1 {
} else if jp.offset0 == 0 || jp.offset1 == -1 {
/*
If the path is evaluated against a value that is not an array,
the result of the evaluation is the same as if the value had been
Expand Down Expand Up @@ -532,13 +561,17 @@ func stepArrayLocationTo(p *PathParser, in []byte) ([]byte, error) {
if in == nil || skip == 0 {
return nil, errInvalid
}

// Upgrade to range
p.path.kind = jpArrayLocationRange

if in[0] >= '0' && in[0] <= '9' {
p.step = stepArrayLocationClose
offset, in2, err := p.lexNumeric(in)
if err != nil {
return nil, err
}
if offset <= p.path.offset0 {
if offset < p.path.offset0 {
return nil, fmt.Errorf("range %d should be >= %d", offset, p.path.offset0)
}
p.path.offset1 = offset
Expand Down
127 changes: 64 additions & 63 deletions go/mysql/json/json_path_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,10 @@ limitations under the License.
package json

import (
"slices"
"fmt"
"testing"

"github.com/stretchr/testify/require"
)

func TestParseJSONPath(t *testing.T) {
Expand All @@ -38,35 +40,33 @@ func TestParseJSONPath(t *testing.T) {
{P: `$.c[last-23 to last-444]`},
{P: `$.c[last-23 to last]`},
{P: `$.c[last]`},
{P: `$.c[last to last]`},
{P: `$.c[0 to 0]`},
{P: `$.c[last - 23 to last]`, Want: `$.c[last-23 to last]`},
{P: `$ . c [ last - 23 to last - 444 ]`, Want: `$.c[last-23 to last-444]`},
{P: `$. "a fish" `, Want: `$."a fish"`},
{P: `$ [last - 3 to last - 1`, Err: "Invalid JSON path expression. The error is around character position 28."},
}

for _, tc := range cases {
var p PathParser
jp, err := p.ParseBytes([]byte(tc.P))
if tc.Err == "" {
if err != nil {
t.Fatalf("failed to parse '%s': %v", tc.P, err)
t.Run(tc.P, func(t *testing.T) {
var p PathParser
jp, err := p.ParseBytes([]byte(tc.P))

if tc.Err != "" {
require.EqualError(t, err, tc.Err)
return
}
} else {
if err == nil {
t.Fatalf("bad parse for '%s': expected an error", tc.P)
} else if err.Error() != tc.Err {
t.Fatalf("bad parse for '%s': expected err='%s', got err='%s'", tc.P, tc.Err, err)

require.NoError(t, err)

want := tc.Want
if want == "" {
want = tc.P
}
continue
}
want := tc.Want
if want == "" {
want = tc.P
}
got := jp.String()
if got != want {
t.Fatalf("bad parse for '%s': want '%s', got '%s'", tc.P, want, got)
}

require.Equal(t, want, jp.String())
})
}
}

Expand All @@ -88,29 +88,33 @@ func TestJSONExtract(t *testing.T) {
{`{"a": 1, "b": 2, "c": [3, 4, 5]}`, `$.*`, []string{"1", "2", "[3, 4, 5]"}},
{`true`, `$[0]`, []string{"true"}},
{`true`, `$[last]`, []string{"true"}},
{`true`, `$[1]`, []string{}},
{`true`, `$[last-1]`, []string{}},
{`true`, `$[0 to 0]`, []string{"true"}},
{`true`, `$[0 to 1]`, []string{"true"}},
{`true`, `$[1 to 2]`, nil},
{`true`, `$[last to last]`, []string{"true"}},
{`true`, `$[last-4 to last]`, []string{"true"}},
{`true`, `$[last-4 to last-1]`, nil},
{`true`, `$[1]`, nil},
{`true`, `$[last-1]`, nil},
{`[ { "a": 1 }, { "a": 2 } ]`, `$**[0]`, []string{`{"a": 1}`, `1`, `{"a": 2}`, `2`}},
{`{ "a" : "foo", "b" : [ true, { "c" : 123, "c" : 456 } ] }`, `$.b[1].c`, []string{"456"}},
{`{ "a" : "foo", "b" : [ true, { "c" : "123" } ] }`, `$.b[1].c`, []string{"\"123\""}},
{`{ "a" : "foo", "b" : [ true, { "c" : 123 } ] }`, `$.b[1].c`, []string{"123"}},
}

for _, tc := range cases {
var matched []string
err := MatchPath([]byte(tc.J), []byte(tc.JP), func(value *Value) {
if value == nil {
return
}
matched = append(matched, string(value.MarshalTo(nil)))
t.Run(fmt.Sprintf("'%s' -> '%s'", tc.J, tc.JP), func(t *testing.T) {
var matched []string
err := MatchPath([]byte(tc.J), []byte(tc.JP), func(value *Value) {
if value == nil {
return
}
matched = append(matched, string(value.MarshalTo(nil)))
})

require.NoError(t, err)
require.Equal(t, tc.Expected, matched)
})
if err != nil {
t.Errorf("failed to match '%s'->'%s': %v", tc.J, tc.JP, err)
continue
}
if !slices.Equal(tc.Expected, matched) {
t.Errorf("'%s'->'%s' = %v (expected %v)", tc.J, tc.JP, matched, tc.Expected)
}
}
}

Expand All @@ -137,63 +141,60 @@ func TestTransformations(t *testing.T) {
const Path1 = `$[1].b[0]`
const Path2 = `$[2][2]`

cases := []struct {
cases := map[string]struct {
T Transformation
Document string
Paths []string
Values []string
Expected string
}{
{
"set operation": {
T: Set,
Document: Document1,
Paths: []string{Path1, Path2},
Values: []string{"1", "2"},
Expected: `["a", {"b": [1, false]}, [10, 20, 2]]`,
},
{
"insert operation": {
T: Insert,
Document: Document1,
Paths: []string{Path1, Path2},
Values: []string{"1", "2"},
Expected: `["a", {"b": [true, false]}, [10, 20, 2]]`,
},
{
"replace operation": {
T: Replace,
Document: Document1,
Paths: []string{Path1, Path2},
Values: []string{"1", "2"},
Expected: `["a", {"b": [1, false]}, [10, 20]]`,
},
{
"remove operation": {
T: Remove,
Document: Document1,
Paths: []string{`$[2]`, `$[1].b[1]`, `$[1].b[1]`},
Expected: `["a", {"b": [true]}]`,
},
}

for _, tc := range cases {
doc := json(t, tc.Document)

var paths []*Path
for _, p := range tc.Paths {
paths = append(paths, path(t, p))
}

var values []*Value
for _, v := range tc.Values {
values = append(values, json(t, v))
}

err := ApplyTransform(tc.T, doc, paths, values)
if err != nil {
t.Fatal(err)
}

result := string(doc.MarshalTo(nil))
if result != tc.Expected {
t.Errorf("bad transformation (%v)\nwant: %s\ngot: %s", tc.T, tc.Expected, result)
}
for name, tc := range cases {
t.Run(name, func(t *testing.T) {
doc := json(t, tc.Document)

var paths []*Path
for _, p := range tc.Paths {
paths = append(paths, path(t, p))
}

var values []*Value
for _, v := range tc.Values {
values = append(values, json(t, v))
}

err := ApplyTransform(tc.T, doc, paths, values)
require.NoError(t, err)

require.Equal(t, tc.Expected, string(doc.MarshalTo(nil)))
})
}
}
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