bug(sniper): fields and local variables with joint declaration cannot be snipered

[fermadeiral]

Hi all,

I have the following code:

        int a, c = 0;

	void foo(int a) {
		a = a;
	}

I want to remove the statement a = a;, which is fine. However, after the sniper printer prints the code, I get: java.lang.IllegalStateException: Registering symbol: 'c' twice in the same scope. This happens because the printed code is:

        int a, c = 0;

	int c = 0;

	void foo(int a);

See, everything is fine with my transformation, but the variable c is printed twice. I created a failing test case to expose this issue, I hope it helps for fixing the bug:

@Test
	public void testPrintOneLineMultipleVariableDeclaration() {
		testSniper(OneLineMultipleVariableDeclaration.class.getName(), type -> {
			CtMethod<?> m = type.getMethodsByName("foo").get(0);
			m.setBody(null);
		}, (type, printed) -> {
			assertIsPrintedWithExpectedChanges(type, printed, "\\Qvoid foo(int a) {\n\t\ta = a;\n\t}", "void foo(int a);");
		});
	}

This is the content of the OneLineMultipleVariableDeclaration class:

package spoon.test.prettyprinter.testclasses;

public class OneLineMultipleVariableDeclaration {

	int a, c = 0;

	void foo(int a) {
		a = a;
	}
}

[monperrus]

For the record, making progress with #3390, #3391, #3392

[fermadeiral]

Nice!

[nharrand]

I've merge the work around!

[fermadeiral]

Thanks @monperrus and @nharrand!

[fermadeiral]

Hi,

The workaround doesn't work for the context I presented here. In my case, I have int a, c = 0;, but in your test you changed it to int a, c;.

The error changed for me now:

spoon.SpoonException: spoon.SpoonException: Unexpected source text: 0;

	at spoon.Launcher.prettyprint(Launcher.java:774)
	at spoon.test.prettyprinter.TestSniperPrinter.testSniper(TestSniperPrinter.java:281)
	at spoon.test.prettyprinter.TestSniperPrinter.testPrintOneLineMultipleVariableDeclaration(TestSniperPrinter.java:113)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: spoon.SpoonException: Unexpected source text: 0;
	at spoon.support.sniper.internal.ElementSourceFragment.onCharSequence(ElementSourceFragment.java:770)
	at spoon.support.sniper.internal.ElementSourceFragment.forEachConstantFragment(ElementSourceFragment.java:728)
	at spoon.support.sniper.internal.ElementSourceFragment.getChildrenFragments(ElementSourceFragment.java:519)
	at spoon.support.sniper.internal.ElementSourceFragment.getGroupedChildrenFragments(ElementSourceFragment.java:538)
	at spoon.support.sniper.internal.SourceFragmentContextNormal.<init>(SourceFragmentContextNormal.java:45)
	at spoon.support.sniper.SniperJavaPrettyPrinter$2.printSourceFragment(SniperJavaPrettyPrinter.java:281)
	at spoon.support.sniper.internal.AbstractSourceFragmentPrinter.print(AbstractSourceFragmentPrinter.java:60)
	at spoon.support.sniper.internal.SourceFragmentContextList.print(SourceFragmentContextList.java:19)
	at spoon.support.sniper.SniperJavaPrettyPrinter$2.printSourceFragment(SniperJavaPrettyPrinter.java:270)
	at spoon.support.sniper.internal.AbstractSourceFragmentPrinter.print(AbstractSourceFragmentPrinter.java:60)
	at spoon.support.sniper.internal.SourceFragmentContextNormal.print(SourceFragmentContextNormal.java:38)
	at spoon.support.sniper.SniperJavaPrettyPrinter.executePrintEventInContext(SniperJavaPrettyPrinter.java:311)
	at spoon.support.sniper.SniperJavaPrettyPrinter.scan(SniperJavaPrettyPrinter.java:241)
	at spoon.support.sniper.SniperJavaPrettyPrinter.scan(SniperJavaPrettyPrinter.java:53)
	at spoon.reflect.visitor.DefaultJavaPrettyPrinter.visitCtCompilationUnit(DefaultJavaPrettyPrinter.java:1092)
	at spoon.support.reflect.declaration.CtCompilationUnitImpl.accept(CtCompilationUnitImpl.java:407)
	at spoon.reflect.visitor.DefaultJavaPrettyPrinter.scan(DefaultJavaPrettyPrinter.java:380)
	at spoon.support.sniper.SniperJavaPrettyPrinter.lambda$superScanInContext$2(SniperJavaPrettyPrinter.java:361)
	at spoon.support.sniper.SniperJavaPrettyPrinter.runInContext(SniperJavaPrettyPrinter.java:372)
	at spoon.support.sniper.SniperJavaPrettyPrinter.superScanInContext(SniperJavaPrettyPrinter.java:361)
	at spoon.support.sniper.SniperJavaPrettyPrinter.access$300(SniperJavaPrettyPrinter.java:54)
	at spoon.support.sniper.SniperJavaPrettyPrinter$2.printSourceFragment(SniperJavaPrettyPrinter.java:281)
	at spoon.support.sniper.internal.AbstractSourceFragmentPrinter.print(AbstractSourceFragmentPrinter.java:60)
	at spoon.support.sniper.internal.SourceFragmentContextList.print(SourceFragmentContextList.java:19)
	at spoon.support.sniper.SniperJavaPrettyPrinter.executePrintEventInContext(SniperJavaPrettyPrinter.java:311)
	at spoon.support.sniper.SniperJavaPrettyPrinter.scan(SniperJavaPrettyPrinter.java:241)
	at spoon.support.sniper.SniperJavaPrettyPrinter.scan(SniperJavaPrettyPrinter.java:53)
	at spoon.reflect.visitor.DefaultJavaPrettyPrinter.calculate(DefaultJavaPrettyPrinter.java:2048)
	at spoon.support.sniper.SniperJavaPrettyPrinter.lambda$calculate$0(SniperJavaPrettyPrinter.java:120)
	at spoon.support.sniper.SniperJavaPrettyPrinter.runInContext(SniperJavaPrettyPrinter.java:372)
	at spoon.support.sniper.SniperJavaPrettyPrinter.calculate(SniperJavaPrettyPrinter.java:115)
	at spoon.support.compiler.jdt.JDTBasedSpoonCompiler.getCompilationUnitInputStream(JDTBasedSpoonCompiler.java:678)
	at spoon.support.compiler.jdt.JDTBasedSpoonCompiler.generateProcessedSourceFilesUsingCUs(JDTBasedSpoonCompiler.java:559)
	at spoon.support.compiler.jdt.JDTBasedSpoonCompiler.generateProcessedSourceFiles(JDTBasedSpoonCompiler.java:211)
	at spoon.Launcher.prettyprint(Launcher.java:772)
	... 24 more

[monperrus]

Thanks @fermadeiral for the follow up, fixed in #3412

[monperrus]

#3412 was only a partial fix, we still have the problem in some cases, see 736bf3a

@algomaster99 would have a look at this sniper limitation?

[algomaster99]

@monperrus I can have a look at it. Can you assign it to me? It can be in my logs that way.

[monperrus]

great, thanks. you're assigned.

[algomaster99]

I think the root of this problem is the ElementSourceFragment tree that is being created. For example, the tree of public class Field { String f1,f2,f3 = "42",f4; } is as follows:

firstChild = {ElementSourceFragment@3860} "|41, 47|public|"
nextSibling = {ElementSourceFragment@3866} " f4;|66, 92|String f1,f2,f3 = "42",f4;|"
  firstChild = {ElementSourceFragment@3894} " f3 = "42",|66, 89|String f1,f2,f3 = "42",|"
     firstChild = {ElementSourceFragment@3899} " f2,|66, 79|String f1,f2,|"
        firstChild = {ElementSourceFragment@3897} "java.lang.String f1,|66, 76|String f1,|"
          firstChild = {ElementSourceFragment@3898} "java.lang.String|66, 72|String|"
             firstChild = {ElementSourceFragment@3900} "java.lang.String|66, 72|String|"
               firstChild = {ElementSourceFragment@3901} "java.lang.String|66, 72|String|"
                 firstChild = {ElementSourceFragment@3903} "java.lang.String|66, 72|String|"

The field declarations are children instead of being siblings of one another and their types are not directly associated with them. We should fix this first otherwise, we will keep working around in the printer and miss some of the edge cases.

Note that this result is after commenting the following lines:

spoon/src/main/java/spoon/support/sniper/internal/ElementSourceFragment.java

Lines 164 to 169 in 58d8d21

	// bug #3386: we cannot handle joint declaration yet
	//so we ignore them, meaning that fields in joint declarations
	// will be reprinted normally
	if (f.isPartOfJointDeclaration()) {
	return;
	}

[algomaster99]

An idea to deal with the above comment is pushed here. It will take a lot of time to reach the goal so I am putting it in my backlog. At least the printer produces a compilable output.