# Replacing one grouped var accepts a leading doc comment, preserves its sibling, and rejects malformed input without a write.
! exec semedit replace-decl --file api/errors.go --symbol ErrAlpha --source 'var ErrAlpha = {'
stderr 'syntax error'
cmp api/errors.go want/api/before.go
exec sh -c 'semedit replace-decl --file api/errors.go --symbol ErrAlpha --source "$(cat api/replacement.txt)"'
exec semedit replace-decl --file api/errors.go --symbol ErrZulu --source 'var ErrZulu = errors.New("updated zulu")'
cmp api/errors.go want/api/errors.go
exec go test ./api

-- go.mod --
module example.com/comments

go 1.23

-- api/errors.go --
package api

import "errors"

var (
	// ErrAlpha is the original sentinel.
	ErrAlpha = errors.New("alpha")
	// ErrZulu stays documented.
	ErrZulu = errors.New("zulu")
)

-- api/replacement.txt --
// ErrAlpha is the updated sentinel.
var ErrAlpha = errors.New("updated alpha")

-- want/api/before.go --
package api

import "errors"

var (
	// ErrAlpha is the original sentinel.
	ErrAlpha = errors.New("alpha")
	// ErrZulu stays documented.
	ErrZulu = errors.New("zulu")
)

-- want/api/errors.go --
package api

import "errors"

var (
	// ErrAlpha is the updated sentinel.
	ErrAlpha = errors.New("updated alpha")
	// ErrZulu stays documented.
	ErrZulu = errors.New("updated zulu")
)