[#IDEADEV-13181] Configurable "assert" calls for "Contants Conditions and exceptions"

IDEA: Development

Configurable "assert" calls for "Contants Conditions and exceptions"

Created: 06 Dec 06 13:42 Updated: 06 Nov 08 23:25

Component/s:

Code Analysis. Inspection

Fix Version/s:

Undefined

Original Estimate:

Unknown

Remaining Estimate:

Unknown

Time Spent:

Unknown

Issue Links:

Duplicate

This issue is duplicated by:
	~~IDEA-14020~~ Mechanism to Designate a method as ha...

Build:	6,112
Severity:	Medium

Description

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A lot of projects out there include custom assertion helpers, see for example http://eclipsezone.com/eclipse/forums/t84288.html
Currently we have the strange situation that an inspection warning like "may throw NPE" appears if and only if some custom assert checks that a variable is not null.

class Assert {
    public static void test(boolean b, String message) {
        if (!b) {
            throw new RuntimeException(message);
        }
    }
}

public class Main {

    public static void foo(JFrame frame) {
        Assert.test(frame != null, "Need a frame");
        frame.setVisible(true);
    }
}

This triggers "may throw NullPointerException" on "frame.setVisible()".
As soon as you remove the preceding Assert the warning vanishes.

I understand this from a technical point of view, but it feels very odd.

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Taras Tielkes - 10 Sep 07 22:07

Stephen, if I understand correctly you'd like to annotate (possibly "external annotate") a method with a @PerformsNullCheck or something similar?

Such an annotation would indeed be nice.

An extra bonus would be: IDEA could index/remember such methods present in module classpath, and automatically provide QuickFixes based on that data.

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Taras Tielkes - 10 Sep 07 22:08

IDEA-14669 is related.

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Yann Cébron - 10 Sep 07 22:25

same goes for Commons Lang "Validate" class, I'd really welcome that RFE

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Stephen Friedrich - 11 Sep 07 11:04

Yup, that's what I have in mind. I am not sure how it's best implemented. You'll definitely need something more flexible than @PerformsNullCheck: You need to specify which of possible multiple parameters is checked for no-nullness.
Also in my example above (from the last project I worked on) there's no dedicated not-null check, but just a simple test method that assert that the first parameter is true.

I would put this much lower on my priority list if this weren't so weird:
frame.setVisible(true);
by itself is not flagged by Idea.
Only if you do assert that frame is non-null by adding
Assert.test(frame != null);
in front of it, then Idea complains that it may be null.

Somehow I technically understand this, but it really makes the constant conditions inspection useless if the project frequently uses custom assert statements.