Inconsistent splitting with long lines

[jtojnar]

Description

The second optionals will get split onto two extra lines, probably since the line spans 110 columns but splitting it vertically only reduces it down three columns – not a very good trade in my opinion.

Small example input

{
  patches =
    attrs.patches or [ ]
    ++ lib.optionals (lib.versionOlder prev.php.version "7.4") [
      ./foo.patch
    ]
    ++ lib.optionals (lib.versionAtLeast prev.php.version "8.0" && lib.versionOlder prev.php.version "8.1") [
      ./bar.patch
    ];
}

Expected output

{
  patches =
    attrs.patches or [ ]
    ++ lib.optionals (lib.versionOlder prev.php.version "7.4") [
      ./foo.patch
    ]
    ++ lib.optionals (lib.versionAtLeast prev.php.version "8.0" && lib.versionOlder prev.php.version "8.1") [
      ./bar.patch
    ];
}

Actual output

{
  patches =
    attrs.patches or [ ]
    ++ lib.optionals (lib.versionOlder prev.php.version "7.4") [
      ./foo.patch
    ]
    ++
      lib.optionals (lib.versionAtLeast prev.php.version "8.0" && lib.versionOlder prev.php.version "8.1")
        [
          ./bar.patch
        ];
}

[piegamesde]

This is an artifact of the line length limit, your expected output exceeds it. If you increase the limit you will get the desired formatting again

[jtojnar]

Right. I am arguing for the line length limit to be a bit more fuzzy.

For example, nixfmt could prefer more compact vertical layout when splitting a line would also overflow the line limit and the reduction of width would be insignificant (it is less than 3% here).