encoding/xml: unexpected behavior of encoder.Indent("", "")

[poffe]

Marshaling xml with prefix and indent set to empty strings results in unindented xml. Tested in Go 1.5.1 darwin/amd64.

The following code:

package main

import (
    "encoding/xml"
    "fmt"
)

type Person struct {
    XMLName   xml.Name `xml:"person"`
    Id        int      `xml:"id,attr"`
    FirstName string   `xml:"name>first"`
    LastName  string   `xml:"name>last"`
    Age       int      `xml:"age"`
}

func main() {
    v := &Person{Id: 13, FirstName: "John", LastName: "Doe", Age: 42}

    output, err := xml.MarshalIndent(v, "", "")
    if err != nil {
        fmt.Printf("error: %v\n", err)
    }

    fmt.Println(string(output))
}

gives:

<person id="13"><name><first>John</first><last>Doe</last></name><age>42</age></person>

but expteded was:

<person id="13">
<name>
<first>John</first>
<last>Doe</last>
</name>
<age>42</age>
</person>

I know, not major, but believe it or not, I actually need the latter behavior. :-)

[ibukanov]

I also assumed that encoder.Indent("", "") should pretty-print with each element on its own line with no indent rather than disabling pretty-print. I need to work with potentially big and rather nested XML. For debugging and friendliness to diff I would like to save files with each element printed on its own line. However even with Indent("", " ") I got a significant increase in file size. I can work-around that with a regexp that strips initial spaces from each line with xml elements, but it would be nice if Indent("", "") worked as expected.

[gopherbot]

Change https://golang.org/cl/102417 mentions this issue: encoding/xml: unexpected behavior of encoder.Indent("", "")

[iwdgo]

MarshalIndent and Marshal share the code. When prefix and indent are
empty, the behaviour is like Marshal when it should have a minimal
indent, i.e. new line.

A boolean is added to the local printer struct which defaults to false.
It is set to true only when MarshalIndent is used and prefix and indent
are empty.

I submitted a minor change to solve this issue.

[gopherbot]

Change https://golang.org/cl/102420 mentions this issue: encoding/xml: fix unexpected behavior of encoder.Indent("", "")

[gopherbot]

Change https://golang.org/cl/108797 mentions this issue: encoding/xml: fix unexpected behavior of encoder.Indent("", "")

[iwdgo]

The fix has been adapted to fix #7113

[gopherbot]

Change https://golang.org/cl/109855 mentions this issue: encoding/xml : Fixes to enforce XML namespace standard