Problems with gin template rendering #912

5455230 · 2025-01-22T02:34:49Z

What version of Garble and Go are you using?

garble version:
mvdan.cc/garble v0.13.0
Build settings:
      -buildmode exe
       -compiler gc
     CGO_ENABLED 1
          GOARCH amd64
            GOOS windows
         GOAMD64 v1

go version:
go version go1.22.5 windows/amd64

What did you do?
[]Item list,iii cannot be printed.

        {{range $value := .iii}}
            value: {{$value.Size}}
        {{end}}

garble build -mod=vendor -o bin/go_go.exe main.go

/main.go

package main

import (
	"net/http"
	"github.com/gin-gonic/gin"
)

type Item struct {
	Page int
	Size int
}

func main() {
	r := gin.Default()
	r.LoadHTMLGlob("templates/*")
	r.GET("/index", func(c *gin.Context) {
		a := gin.H{
			"title": "titleAA",
			"ce":    "123456",
			"iii": []Item{
				{Page: 1, Size: 11},
				{Page: 2, Size: 12},
				{Page: 3, Size: 13},
			},
		}
		c.HTML(http.StatusOK, "index.html", a)
	})
	r.Run()
}

/templates/index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <title>{{.title}}</title>
</head>
    <body>
        iii:
        {{range $value := .iii}}
            value: {{$value.Size}}
        {{end}}
    </body>
</html>

GET:http://127.0.0.1:8080/index
Error #01: template: index.html:9:27: executing "index.html" at <$value.Size>: can't evaluate field Size in type main.B0aMZmq6

The text was updated successfully, but these errors were encountered:

5455230 · 2025-01-22T02:40:45Z

/main.go

"iii": Item{Page: 1, Size: 11}

/templates/index.html

{{.iii.Size}}

struct{} writing methods can be rendered successfully.

Error with []struct{} type in gin template rendering.

lu4p · 2025-01-22T20:22:11Z

This is likely fixed in master:

go install mvdan.cc/garble@master

5455230 · 2025-01-23T00:50:21Z

This is likely fixed in master:

go install mvdan.cc/garble@master

go install mvdan.cc/garble@master
OR
go get -u mvdan.cc/garble@master

What version of Garble and Go are you using?

garble version:
mvdan.cc/garble v0.13.1-0.20250119141355-97833204f8f2
Build settings:
      -buildmode exe
       -compiler gc
     CGO_ENABLED 1
          GOARCH amd64
            GOOS windows
         GOAMD64 v1

go version:
go version go1.23.5 windows/amd64

go.mod:
mvdan.cc/garble v0.13.1-0.20250119141355-97833204f8f2
go.sum:

mvdan.cc/garble v0.13.1-0.20250119141355-97833204f8f2 h1:KbpHDqitrM8UW68FcQ3ehobmldqmyLjmuZkwO82xva0=
mvdan.cc/garble v0.13.1-0.20250119141355-97833204f8f2/go.mod h1:QOG7wThB5kAQhih4m93Sk1kjiGT8pgcEvWi/+VTWEn0=

Go->cmd:
SET CGO_ENABLED=0 && SET GOOS=windows && SET GOARCH=amd64 && garble build -o bin/go_go.exe main.go

GET:http://127.0.0.1:8080/index
Error #1: template: index.html:9:27: executing "index.html" at <$value.Size>: can't evaluate field Size in type main.ORh2JaE4Gpg8

I seem to have found some clues (not sure).

iii := map[string]interface{}{"Page": 1, "Size": "11"}
fmt.Println(fmt.Printf("%+v", iii)) //map[Page:1 Size:11]

OR

iii := []map[string]interface{}{
	{"Page": 1, "Size": "11"},
	{"Page": 2, "Size": "12"},
	{"Page": 3, "Size": "13"},
}
fmt.Println(fmt.Printf("%+v", iii)) //[map[Page:1 Size:11] map[Page:2 Size:12] map[Page:3 Size:13]]

any and interface{} Obfuscation was not successfully performed.

Error #01: template: index.html:9:27: executing "index.html" at <$value.Size>: can't evaluate field Size in type main.B0aMZmq6

The reason for the error is that []Item{} liststruct has successfully executed the code confusion, but template: index.html:9:27 fails to correspond to the variable name after confusion.
(But I personally have no ability to repair this problem,sorry)

lu4p · 2025-01-23T11:37:57Z

Can you share a full example to reproduce this?

5455230 · 2025-01-23T12:46:24Z

Can you share a full example to reproduce this?

The complete file example is at the beginning of the post, with only two files (/main.go and /templates/index.html)

5455230 · 2025-01-30T13:17:40Z

package main

import (
	"fmt"
	"html/template"

	"github.com/gin-gonic/gin"
)

// SET CGO_ENABLED=0&&SET GOOS=windows&&SET GOARCH=amd64&&garble build -o bin/go_build_main_go.exe main.go
func main() {
	r := gin.Default()
	// r.LoadHTMLGlob("templates/*")
	tmpl := template.Must(template.New("index.html").Parse(`
		<!DOCTYPE html>
		<html lang="en">
		<head>
			<title>{{.title}}</title>
		</head>
			<body>
				iii:
				{{range $value := .iii}}
					value: {{$value.Size}}
				{{end}}
			</body>
		</html>
	`))
	r.SetHTMLTemplate(tmpl)
	r.GET("/index", func(c *gin.Context) {
		type Item struct {
			Page int
			Size string
		}
		aaa := []Item{
			{Page: 1, Size: "11"},
			{Page: 2, Size: "12"},
			{Page: 3, Size: "13"},
		}
		a := gin.H{
			"title": "titleAA",
			"ce":    "123456",
			"iii":   aaa,
			"aaa": []Item{
				{Page: 1, Size: "11"},
				{Page: 2, Size: "12"},
				{Page: 3, Size: "13"},
			},
		}
		c.HTML(200, "index.html", a)
	})
	r.Run()
}

This example(main.go) has the same error prompt as the example above.

Xiol · 2025-02-04T11:19:15Z

I am having a similar problem, although my use case is different. I can replicate my issue with this code, which replicates what I'm doing in my application:

package main

import (
	"embed"
	"fmt"
	"os"
	"strings"
	"text/template"
)

//go:embed templates
var templateFS embed.FS

type TemplateData struct {
	Name  string
	Value string
	Port  int
}

func RenderTemplate[T any](src string, dest string, data T) error {
	content, err := templateFS.ReadFile(src)
	if err != nil {
		return fmt.Errorf("failed to read template: %w", err)
	}

	tmpl, err := template.New(src).Parse(string(content))
	if err != nil {
		return fmt.Errorf("failed to parse template: %w", err)
	}

	var buf strings.Builder
	if err := tmpl.Execute(&buf, data); err != nil {
		return fmt.Errorf("failed to execute template: %w", err)
	}

	return os.WriteFile(dest, []byte(buf.String()), 0644)
}

func main() {
	data := TemplateData{
		Name:  "test",
		Value: "example",
		Port:  8080,
	}

	if err := RenderTemplate("templates/config.yaml.tmpl", "config.yaml", data); err != nil {
		fmt.Printf("Error rendering template: %v\n", err)
		os.Exit(1)
	}
}

In the same directory, create another directory called templates and add this as config.yaml.tmpl:

name: {{.Name}}
value: {{.Value}}
port: {{.Port}}

Directory structure should then match:

.
├── main.go
└── templates/
    └── config.yaml.tmpl

Running this with go run main.go results in the template being rendered correctly:

❯ go run main.go
❯ cat config.yaml
name: test
value: example
port: 8080

Running it with garble run main.go results in the error as reported by others:

❯ garble run main.go
Error rendering template: failed to execute template: template: templates/config.yaml.tmpl:1:8: executing "templates/config.yaml.tmpl" at <.Name>: can't evaluate field Name in type main.BuHbPeMsq
exit status 1
exit status 1

lu4p added the bug Something isn't working label Feb 18, 2025

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Problems with gin template rendering #912

Problems with gin template rendering #912

5455230 commented Jan 22, 2025 •

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lu4p commented Jan 22, 2025

5455230 commented Jan 23, 2025 •

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lu4p commented Jan 23, 2025

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5455230 commented Jan 30, 2025

Xiol commented Feb 4, 2025

Problems with gin template rendering #912

Problems with gin template rendering #912

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