golang template.ParseGlob not reading files in root directory

Question

I have a golang code as follows

package main

import (
    "html/template"
    "os"
    "path/filepath"
)

func main() {
    // Parse all templates that match the recursive glob pattern
    templates := template.Must(template.ParseGlob(filepath.Join("templates", "**", "*.gohtml")))

    // Execute the base template to render the combined content
    err := templates.ExecuteTemplate(os.Stdout, "base.gohtml", nil)
    if err != nil {
        panic(err)
    }
}

and the templates are in the following structure

templates
├── base.gohtml
└── nested
    └── index.gohtml

when I run this program, it's showing this error

panic: html/template: "base.gohtml" is undefined

goroutine 1 [running]:
main.main()

when I move the base.gohtml into nested directory, it works as expected. is there any problem with the pattern ?

Answer 1

In your program filepath.Join("templates", "**", "*.gohtml") gives you a file path that should match templates/**/*.gohtml and since we have /**/ in there it should match any directory but not root, and then inside that directory any gohtml file which is why files in the template dir are not getting matched but everything inside nested is. And if you have any other dir, the gohtml files inside it would also get matched.

So yeah there is a problem with the pattern and more details can be found in go docs

Also more can be found out on Issue#11862 on go's repo!