Chained method calls aligned incorrectly

[yurikhan]

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.3 LTS
Release:	20.04
Codename:	focal

$ clang-format-12 --version
Ubuntu clang-format version 12.0.0-3ubuntu1~20.04.4

.clang-format:

IndentWidth: 4
TabWidth: 4
UseTab: ForContinuationAndIndentation

Observed indentation:

struct Foo {
→   Foo &long_named_self_returning_method();
};

int main() {
→   auto foo = Foo{}
→   →   →   →   ···.long_named_self_returning_method()
→   →   →   →   ···.long_named_self_returning_method()
→   →   →   →   ···.long_named_self_returning_method()
→   →   →   →   ···.long_named_self_returning_method();
}

Specifically, it looks like continuation lines are indented +4 relative to the expression start Foo{}.

Desired indentation:

struct Foo {
→   Foo &long_named_self_returning_method();
};

int main() {
→   auto foo = Foo{}
→   →   .long_named_self_returning_method()
→   →   .long_named_self_returning_method()
→   →   .long_named_self_returning_method()
→   →   .long_named_self_returning_method();
}

i.e. indent continuation lines relative to the start of preceding line.

I especially consider it a bug to emit the sequence <tab><space>. It will break every reader who uses a different tab width.

[mgerhold]

Any news on this? 🤔

[EugeneZelenko]

Could you please try 18 or main branch?

[yurikhan]

@EugeneZelenko Same behavior on 18.1.3 as packaged by Ubuntu 24.04.

[yurikhan]

Same behavior on 18.1.8 as packaged in Ubuntu 24.10.

[mgerhold]

I also tested with 18.1.8 on Windows 11. Same behavior.

[Davidbrcz]

Still present with 19.1.1

With this config:

TabWidth: 0
UseTab: Never
ContinuationIndentWidth: 4

This works:

    Dummy chainedMethods() {
        return chainedMethods()
            .chainedMethods()
            .chainedMethods()
            .chainedMethods()
            .chainedMethods()
            .chainedMethods()
            .chainedMethods()
            .chainedMethods()
            .chainedMethods();
    }

This doesn't:

    Dummy chainedMethods() {
        var a = chainedMethods()
                    .chainedMethods()
                    .chainedMethods()
                    .chainedMethods()
                    .chainedMethods()
                    .chainedMethods()
                    .chainedMethods()
                    .chainedMethods()
                    .chainedMethods();
        return a;
    }

[justineakehurst]

I would like to see this fixed as clang-format is unable to be configured to perform line-wrapping according to style(9):

Indentation is an 8 character tab.  Second level indents are four
spaces. If you have to wrap a long statement, put the operator at the
end of the line.

while (cnt < 20 && this_variable_name_is_too_long &&
    ep != NULL)
        z = a + really + long + statement + that + needs +
            two + lines + gets + indented + four + spaces +
            on + the + second + and + subsequent + lines;

I'm also seeing this particular problem manifest in this hypothetical example:

function_1(function_2(function_3(param),
            "this is a string param") == 0,
    "this is another string param");

which should be:

function_1(function_2(function_3(param),
    "this is a string param") == 0,
    "this is another string param");