Do not adopt Arrays.toString for varargs arguments

[timtebeek]

Fixes #230

What's changed

In this proposal we look at the method parameter type, and if that is also an array we do not produce a change.

Anything in particular you'd like reviewers to focus on?

Not sure I actually like this change yet; It seems before we were too eager to make changes, even where we changed to logic. The recipe was intended not to show the result of arr.toString(), that that wasn't what happened on some of the previous cases. Take for example

jshell> String[] args = new String[] {"a","b","c"}
args ==> String[3] { "a", "b", "c" }

jshell> String.format("s=%s", args)
|  Warning:
|  non-varargs call of varargs method with inexact argument type for last parameter;
|    cast to java.lang.Object for a varargs call
|    cast to java.lang.Object[] for a non-varargs call and to suppress this warning
|  String.format("s=%s", args)
|                        ^--^
$6 ==> "s=a"

Note

How we print s=a, not s=[Ljava.lang.String;@73a8dfcc as would be the case for args.toString()

That means that the recipe might inadvertently in the old situation changes the above to start producing
s=[a, b, c] for String.format("s=%s", Arrays.toString(args))

[timtebeek]

@philippe-granet do these changes align with what you expected after logging

• RemoveToStringCallsFromArrayInstances should not use Arrays.toString on String/PrintStream/PrintWriter.format methods #230 ?

[philippe-granet]

@philippe-granet do these changes align with what you expected after logging

• RemoveToStringCallsFromArrayInstances should not use Arrays.toString on String/PrintStream/PrintWriter.format methods #230 ?

@timtebeek yes it's OK for me, thanks!

[knutwannheden]

An alternative would be to rely on Flag.Varargs which when set on the JavaType.Method means that it is a varargs method.

[timtebeek]

Didn't know that flag, thanks! But then that only applies to the entire method right? Yet we'd still want to do replacements on String.format and friends when we can. Say String.format gets called with 6 arguments, one of them is an array. The current implementation would then still wrap that one array in Arrays.toString. Or how would you apply that flag here?

[knutwannheden]

Not sure. I would probably just use the flag to check what the recipe should do with the arguments corresponding to the (last) varargs parameter, if any. Probably no huge improvement...