Nunjucks: Trailing newline output from include even with whitespace stripping

[dgirgenti]

I have the following template code in our codebase that renders Jinja2 and/or Nunjucks depending on the situation:

<a href="#">
    {%- include 'logo.j2' -%}{%- include 'icon.j2' -%}
</a>

where logo.j2 and icon.j2 both contain a single <svg>

Jinja2 is rendering this how I would expect, where I get ...</svg><svg>... in my output. However, Nunjucks is insisting on returning ...</svg>\n<svg>... no matter what I try. How can I have these tags touch in the output?

[fdintino]

Ah, I see the issue. From the jinja2 docs:

By default, Jinja2 also removes trailing newlines. To keep single trailing newlines, configure Jinja to keep_trailing_newline.

We don't copy this behavior in nunjucks, and I'm actually rather surprised that Jinja2 does this by default. From this discussion it sounds like it was originally a bug, or at least unintentional, but folks started relying on the trailing-newline-stripping so they made it configurable with a setting to keep backwards compatibility.

I'm not sure it makes sense to follow jinja2's lead on this, though I could be convinced otherwise. The most straightforward way to get rid of the \n is to remove the trailing newline in the included files.

[fdintino]

Maybe I'm overstating it by saying that it was originally unintentional. If the only thing being rendered is html, and given that some editors always add a trailing newline to a file, I can understand why some might find the trailing-newline-stripping preferable. And since {% include %} isn't part of an open/close tag, I could see why {%- include -%} might be expected to do to the included file what it would have done for {%- if -%}...{%- endif -%}

[dgirgenti]

So, would it be possible or favorable to at least add a global flag/option to Nunjucks to get it to behave the same as Jinja2's default behavior?