add on `null` does not work anymore ?

[eddycharly]

Looks like applying an add patch to null now panics: https://go.dev/play/p/qo2WNSqwpYZ

package main

import (
	"fmt"

	jsonpatch "github.com/evanphx/json-patch/v5"
)

func main() {
	original := []byte(`null`)
	patchJSON := []byte(`[{"op": "add", "path": "/version", "value": "0.2.0"}]`)
	patch, err := jsonpatch.DecodePatch(patchJSON)
	if err != nil {
		panic(err)
	}
	options := &jsonpatch.ApplyOptions{EnsurePathExistsOnAdd: true}
	modified, err := patch.ApplyWithOptions(original, options)
	if err != nil {
		panic(err)
	}

	fmt.Printf("Original document:\n%s\n", original)
	fmt.Printf("Modified document:\n%s\n", modified)
}

panic: assignment to entry in nil map

goroutine 1 [running]:
github.com/evanphx/json-patch/v5.(*partialDoc).set(...)
	/tmp/gopath2668474575/pkg/mod/github.com/evanphx/json-patch/v5@v5.8.1/patch.go:570
github.com/evanphx/json-patch/v5.(*partialDoc).add(0xc0000161b0, {0xc000012120, 0x7}, 0xc0000600e0, 0x496328?)
	/tmp/gopath2668474575/pkg/mod/github.com/evanphx/json-patch/v5@v5.8.1/patch.go:575 +0x176
github.com/evanphx/json-patch/v5.Patch.add({0xc000012028?, 0x4?, 0x4?}, 0xc000104e60, 0xc0000161b0?, 0xc00001a078)
	/tmp/gopath2668474575/pkg/mod/github.com/evanphx/json-patch/v5@v5.8.1/patch.go:781 +0x25e
github.com/evanphx/json-patch/v5.Patch.ApplyIndentWithOptions({0xc000060040?, 0x1, 0x4}, {0xc000012028, 0x4, 0x4}, {0x0, 0x0}, 0x60?)
	/tmp/gopath2668474575/pkg/mod/github.com/evanphx/json-patch/v5@v5.8.1/patch.go:1221 +0x2d9
github.com/evanphx/json-patch/v5.Patch.ApplyWithOptions(...)
	/tmp/gopath2668474575/pkg/mod/github.com/evanphx/json-patch/v5@v5.8.1/patch.go:1174
main.main()
	/tmp/sandbox724842672/prog.go:17 +0x105

Program exited.

[evanphx]

Shouldn't panic, that's a bug I'll fix now. But I don't think it's valid either.

[eddycharly]

Thanks, it used to work in 5.7.0 and below (at least with EnsurePathExistsOnAdd: true)

[evanphx]

@eddycharly what did it do? Why were you using it?

[evanphx]

Looks like in v5.7.0, it returned an error about the json document...

[eddycharly]

Yes, in v5.7.0 it returned an error failed to patch resource: unexpected JSON token in document node: <nil>.

[evanphx]

kk, I'll have a 5.8.2 out shortly that fixes this.

[eddycharly]

@evanphx are you still planing a fix release soon ?

shall I give it a try and open a PR ? would that help ?

[evanphx]

Sorry for the delay, dealing with this today.

[evanphx]

5.9.0 is out now with the fix!

[eddycharly]

Thanks, trying it out !