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

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arthurschreiber wants to merge 5 commits into from
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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
8 changes: 8 additions & 0 deletions go/mysql/json/json_path_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,8 @@ 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: `$."a fish"`},
Expand Down Expand Up @@ -88,6 +90,12 @@ func TestJSONExtract(t *testing.T) {
{`{"a": 1, "b": 2, "c": [3, 4, 5]}`, `$.*`, []string{"1", "2", "[3, 4, 5]"}},
{`true`, `$[0]`, []string{"true"}},
{`true`, `$[last]`, []string{"true"}},
{`true`, `$[0 to 0]`, []string{"true"}},
{`true`, `$[0 to 1]`, []string{"true"}},
{`true`, `$[1 to 2]`, []string{}},
{`true`, `$[last to last]`, []string{"true"}},
{`true`, `$[last-4 to last]`, []string{"true"}},
{`true`, `$[last-4 to last-1]`, []string{}},
{`true`, `$[1]`, []string{}},
{`true`, `$[last-1]`, []string{}},
{`[ { "a": 1 }, { "a": 2 } ]`, `$**[0]`, []string{`{"a": 1}`, `1`, `{"a": 2}`, `2`}},
Expand Down
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