Using `render.MustTemplate` with chart causes parsing error

[Logan Jones]

When attempting to use the base template with my chart I get this template parsing error function "safeJS" not defined. This led me to see that the render.MustTemplate function does not add the function safeJS to the template before calling parse on the template.

https://pkg.go.dev/text/template#Template.Funcs
States that

Funcs adds the elements of the argument map to the template's function map. It must be called before the template is parsed.

I've tested making the tweak to render.MustTemplate to abide by this requirement and it works correctly now.

[Koy Zhuang]

Hi @LJ-Software , could plz provide a tiny reproduce demo? thx.

[Logan Jones]

@Koooooo-7 Sure, I was able to get the same error with this code:

package main

import (
  "bytes"
  "log"
  
  "github.com/go-echarts/go-echarts/v2/charts"
  "github.com/go-echarts/go-echarts/v2/render"
  "github.com/go-echarts/go-echarts/v2/templates"
)

func main() {
  graph := charts.NewGraph()
  contents := []string{templates.BaseTpl, templates.ChartTpl, templates.HeaderTpl}
  tpl := render.MustTemplate("chart", contents) 
  buf := new(bytes.Buffer)
  if err := tpl.ExecuteTemplate(buf, "chart", graph); err != nil { 
    log.Panic("could not execute template")
  }
}

the error:

panic: template: chart:9: function "safeJS" not defined

goroutine 1 [running]:
html/template.Must(...)
        /usr/local/Cellar/go/1.20.3/libexec/src/html/template/template.go:368
github.com/go-echarts/go-echarts/v2/render.MustTemplate({0x1196f25?, 0xc0000061a0?}, {0xc000151f40?, 0x3?, 0x3?})
        /Users/ljones/go/pkg/mod/github.com/go-echarts/go-echarts/v2@v2.2.6/render/engine.go:108 +0x237
main.main()
        /Users/ljones/Development/echarts-bug-min-example/main.go:15 +0xab
exit status 2

[Logan Jones]

Would it be possible to get a new release tag off the master branch with this fix in? @Koooooo-7

[Koy Zhuang]

Would it be possible to get a new release tag off the master branch with this fix in? @Koooooo-7

No prob, I gonna have a patch release on it, and you could tag the commit id as workaround.

[Koy Zhuang]

FYI @LJ-Software , v2.2.7 released.