html/template: broken after clone

[jbeda]

See https://play.golang.org/p/r83esZdCzY.

package main

import "os"
import "fmt"
import "html/template"

func main() {
    t := template.New("name")
    t, _ = t.Clone()
    t = template.Must(t.Parse("stuff"))
    err := t.Execute(os.Stdout, nil)
    if err != nil {
        fmt.Printf("Error: %v", err)
    }
}

Produces:

Error: template: "name" is an incomplete or empty template; defined templates are: "name"

For the "source" template, it looks like Clone creates two copies.

I think adding this in the loop (after the definition of name would fix it):

if name == ret.text.Name() {
  ret.set[name] = ret
  continue
}

[gopherbot]

CL https://golang.org/cl/16104 mentions this issue.

[adg]

For the "source" template, it looks like Clone creates two copies.

What does this mean?

[jbeda]

"Source" means the template that you are cloning from. Looks like it creates the copy directly and another in the "textClone.Templates()" loop. You can see how text/template Clone deals with it here: https://github.com/golang/go/blob/master/src/text/template/template.go#L89

[nodirt]

@jbeda it does not create two copies of itself because, unlike html/template, in text/template Template.Templates() doesn't return itself

[gopherbot]

CL https://golang.org/cl/31092 mentions this issue.