BUG: HTMLRelated attachments with only HTML

[martinrode]

• Composing an Email with HTMLRelated attachement and only HTML body
• NO Text Body
• This crashes with a

Stack:
goroutine 804 [running]:
runtime/debug.Stack(0xc001f147e0, 0x5145b60, 0x645ad70)
        /usr/local/go/src/runtime/debug/stack.go:24 +0x9d
github.com/programmfabrik/fylr/pkg/server/middleware.Environment.func1.1(0xc001f147e0, 0x590f560, 0xc001f20540, 0xc00209b500)
        /Users/martin/go/src/github.com/programmfabrik/fylr/pkg/server/middleware/environment.go:32 +0x6b
panic(0x5145b60, 0x645ad70)
        /usr/local/go/src/runtime/panic.go:969 +0x166
mime/multipart.(*Writer).CreatePart(0x0, 0xc002376710, 0x53030ed, 0xc, 0xc0023767f8, 0xc000d55740)
        /usr/local/go/src/mime/multipart/writer.go:98 +0x3a
github.com/jordan-wright/email.(*Email).Bytes(0xc002376c70, 0xc0006d61a0, 0x10, 0x0, 0x0, 0x0)
        /Users/martin/go/pkg/mod/github.com/jordan-wright/email@v0.0.0-20200602115436-fd8a7622303e/email.go:452 +0xb43
github.com/jordan-wright/email.(*Email).Send(0xc002376c70, 0x530c490, 0x12, 0x59069e0, 0xc002834340, 0xc001e43f93, 0x9)
        /Users/martin/go/pkg/mod/github.com/jordan-wright/email@v0.0.0-20200602115436-fd8a7622303e/email.go:519 +0x3ab

[jordan-wright]

Hey there!

Could you please provide a sample email that I can use to reproduce the issue?

[martinrode]

Hi Jordan,

simply set HTML, Attachment (HTMLRelated), and no Text.

The logic in „Bytes“ set isMixed and isAlternative both to false and later when adding the html attachment the subWriter is nil.

I dont know enough about email, but I assume the isMixed or isAlternative need to be turned on in this case where the mail requires an HTML body and an attachment.

If you need code, I can provide this on Monday when I am back in the office.

Best, Martin

[sgoldenb]

Since i stumbled upon the same bug here something to reproduce:

// *Mailer contains the pool and some config stuff
func (m *Mailer) Send(e *email.Email) error {
    d := struct {
        Text          string
    }{
        Text:         "whatever" ,
    }

        // the template references the image via cid
        temp, err := m.parseTemplate("my_template.html", d)
    if err != nil {
             return err
       }
    e := email.NewEmail()
    e.HTML = temp
    e.From = "no-reply@foo.bar"
    e.Subject = "Blarb"
    e.To = []string{"foo@bar.baz"}

    dir, _ := os.Getwd()
    a, _ := e.AttachFile(dir+"/mailer/logo.png")

    // set to multipart to embed image
    a.HTMLRelated = true

    // text needs to be set to something non empty for multipart attachments to work
    // uncommenting this line will cause the crash 
    // e.Text = []byte(" ")

    return m.pool.Send(e, m.timeout)
}