Change "qualified Invocations" wrapping option to improve fluent API formatting

[redhead]

I was surprised that custom wrapped code in a long method call chains is reformatted back to a single line. Affects stream() or any builder methods. For example:

    return GraphQLArgument.newArgument()
            .name(argName)
            .type(argType)
            .description(description)
            .defaultValue(argDefaultValue)
            .build();

Becomes:

	return GraphQLArgument.newArgument().name(argName).type(argType).description(description)
			.defaultValue(argDefaultValue).build();

This does not improve readability IMHO.

[wilkinsona]

This is how Eclipse's formatter, upon which Java Format is based, works. If you want to keep the separate lines in certain cases you can disable the formatter.

[gberche-orange]

@wilkinsona with large adoption of builder, fluent apis, including reactor codebase, the proportion of affected code by this limitation increases, and this becomes impracticable to disable formatting for such large proportion of code. This prevents uses of the spring-javaformat in affected projects (e.g. spring-cloud/spring-cloud-app-broker#291 (comment))

Any chance to reopen this issue to discuss how to find solutions ?

Googling "eclipse formatter for fluent apis" leads to the discussions/issues below, could they be applicable and useful to spring-javaformat ?

https://bugs.eclipse.org/bugs/show_bug.cgi?id=547558 Formatter for lamda expression
https://bugs.eclipse.org/bugs/show_bug.cgi?id=489444 [Formatter] Chained method calls when using Stream API or builders should have different behavior from other method calls.
https://stackoverflow.com/questions/4172937/how-to-indent-the-fluent-interface-pattern-correctly-with-eclipse?rq=1

/CC @royclarkson

[wilkinsona]

Thanks for the references. I think they show that there's nothing that we can do here at the moment, particularly https://bugs.eclipse.org/bugs/show_bug.cgi?id=489444 which remains open.

[gberche-orange]

I wonder whether the existing flag line wrapping -> function calls -> qualified invocations was considered as an improvement over the single liner reported in this issue ?

https://bugs.eclipse.org/bugs/show_bug.cgi?id=547558#c2

[redhead]

In the end, we went the way that it's up to the programmer to decide the line breaks in every particular case. Thus, we don't restrict everything to one line nor splitting it per line every time (sometimes some short builder method chain or simple stream pipeline don't need to be wrapped). This, however, makes it relaxed enough to the point programmers are able to do line breaks anywhere they want, for example, in the middle of parameter list. It's not ideal, as we need to keep an eye out in the reviews, but still better than forcing everything on one line.

[JanecekPetr]

Hello, I'm sorry to resurrect this, but I feel even though Mr. Wilkinson is probably aware of what we're talking about, he didn't actually address it explicitly. Eclipse already supports nice formatting of chained method calls, like the stream calls or any fluent calls, via the Qualified Invocations option. How does this not solve the problem?

In Eclipse, this:

results in this code:

return SomeClass.builder()
	.aha(AhaConverter.convert(message))
	.uuid(UUID.randomUUID())
	.timeReceived(ZonedDateTime.now())
	.build();

That's exactly what we want and should also be available programatically. If there's consensus on the change I'll gladly try and help with the code changes and the required communication to downstream projects (might require a major/minor version bump?).

Let's please make the plugin actually useful by providing readable code :(

[philwebb]

I seem to remember the last time I looked at this I wasn't too happy with the results when we applied them to the Spring Boot codebase. I'll reopen the issue to check again, perhaps I was using a different setting.