Error when formatting sigils containing newlines

[gustawlippa]

When trying to format code containing multiline sigils:

-module(test).

-export([hello/0]).

hello() ->
    ~"Hello
             there".

An error is reported:

test.erl:5:1: formatter result not equivalent. Please report this bug.

Hence I'm reporting the error - not sure how popular this sigil usage is though 😅

However, it's legal Erlang code. It compiles without warnings, and the sigil is properly handled:

1> test:hello().
<<"Hello\n             there">>

[michalmuskala]

Thank you for the report. I'm on holiday now, but I'll take a look once I'm back.

The error is likely related to the newline inside the sigil - it's possible we don't handle that case correctly. Converting to an explicit \n character might be a mitigation.

[williamthome]

I can confirm the issue occurs because erlfmt's multiline string transformation logic doesn't preserve sigil context.

When it encounters:

~"
    foo
    "

It applies the standard string splitting that works for regular strings ("a\nb" → "a\n" "b"), but creates invalid mixed syntax:

~"\n"
"    foo\n"
"    "

Where only the first part remains a sigil.