Attachment #189794 for bug #336428




 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Stephan Herrmann - contribution for Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.flow;


				if ((this.tagBits & FlowContext.HIDE_NULL_COMPARISON_WARNING) == 0) {
					recordNullReference(local, reference, checkType);
				}
			} else if (flowInfo.cannotBeDefinitelyNullOrNonNull(local)) {
				return; // no reason to complain, since there is definitely some uncertainty making the comparison relevant.
			} else {
				if ((this.tagBits & FlowContext.HIDE_NULL_COMPARISON_WARNING) == 0) {
					// note: pot non-null & pot null is already captured by cannotBeDefinitelyNullOrNonNull()
					if (flowInfo.isPotentiallyNonNull(local)) {
						// knowing 'local' can be non-null, we're only interested in seeing whether it can *only* be non-null 
						recordNullReference(local, reference, CAN_ONLY_NON_NULL | checkType & CONTEXT_MASK);
					} else if (flowInfo.isPotentiallyNull(local)) {
						// knowing 'local' can be null, we're only interested in seeing whether it can *only* be null
						recordNullReference(local, reference, CAN_ONLY_NULL | checkType & CONTEXT_MASK);
					} else {
						recordNullReference(local, reference, checkType);
					}
				}

Lines 8-14 Link Here

(-)src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java (-2 / +151 lines)
8	* Contributors:	8	* Contributors:
9	* IBM Corporation - initial API and implementation	9	* IBM Corporation - initial API and implementation
10	* Stephan Herrmann <stephan@cs.tu-berlin.de> - Contributions for	10	* Stephan Herrmann <stephan@cs.tu-berlin.de> - Contributions for
11	* bugs 325755, 133125, 292478, 319201, 320170 and 332637	11	* bug 325755 - [compiler] wrong initialization state after conditional expression
		12	* bug 133125 - [compiler][null] need to report the null status of expressions and analyze them simultaneously
		13	* bug 292478 - Report potentially null across variable assignment
		14	* bug 319201 - [null] no warning when unboxing SingleNameReference causes NPE
		15	* bug 320170 - [compiler] [null] Whitebox issues in null analysis
		16	* bug 332637 - Dead Code detection removing code that isn't dead
		17	* bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
12	*******************************************************************************/	18	*******************************************************************************/
13	package org.eclipse.jdt.core.tests.compiler.regression;	19	package org.eclipse.jdt.core.tests.compiler.regression;
14		20
Lines 36-42 Link Here
36	// Only the highest compliance level is run; add the VM argument	42	// Only the highest compliance level is run; add the VM argument
37	// -Dcompliance=1.4 (for example) to lower it if needed	43	// -Dcompliance=1.4 (for example) to lower it if needed
38	static {	44	static {
39	// TESTS_NAMES = new String[] { "testBug325229" };	45	// TESTS_NAMES = new String[] { "testBug336428e" };
40	// TESTS_NUMBERS = new int[] { 561 };	46	// TESTS_NUMBERS = new int[] { 561 };
41	// TESTS_RANGE = new int[] { 1, 2049 };	47	// TESTS_RANGE = new int[] { 1, 2049 };
42	}	48	}
Lines 13833-13838 Link Here
13833	"");	13839	"");
13834	}	13840	}
13835		13841
		13842	// Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
		13843	// original issue
		13844	public void testBug336428() {
		13845	this.runConformTest(
		13846	new String[] {
		13847	"DoWhileBug.java",
		13848	"public class DoWhileBug {\n" +
		13849	" void test(boolean b1, Object o1) {\n" +
		13850	" Object o2 = new Object();\n" +
		13851	" do {\n" +
		13852	" if (b1)\n" +
		13853	" o1 = null;\n" +
		13854	" } while ((o2 = o1) != null);\n" +
		13855	" }\n" +
		13856	"}"
		13857	},
		13858	"");
		13859	}
		13860	// Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
		13861	// hitting the same implementation branch from within the loop
		13862	// information from unknown o1 is not propagated into the loop, analysis currently believes o2 is def null.
		13863	public void _testBug336428a() {
		13864	this.runConformTest(
		13865	new String[] {
		13866	"DoWhileBug.java",
		13867	"public class DoWhileBug {\n" +
		13868	" void test(boolean b1, Object o1) {\n" +
		13869	" Object o2 = null;\n" +
		13870	" do {\n" +
		13871	" if (b1)\n" +
		13872	" o1 = null;\n" +
		13873	" if ((o2 = o1) != null)\n" +
		13874	" break;\n" +
		13875	" } while (true);\n" +
		13876	" }\n" +
		13877	"}"
		13878	},
		13879	"");
		13880	}
		13881
		13882	// Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
		13883	// in this variant the analysis believes o2 is def unknown and doesn't even consider raising a warning.
		13884	public void _testBug336428b() {
		13885	this.runNegativeTest(
		13886	new String[] {
		13887	"DoWhileBug.java",
		13888	"public class DoWhileBug {\n" +
		13889	" void test(boolean b1) {\n" +
		13890	" Object o1 = null;\n" +
		13891	" Object o2 = null;\n" +
		13892	" do {\n" +
		13893	" if ((o2 = o1) == null) break;\n" +
		13894	" } while (true);\n" +
		13895	" }\n" +
		13896	"}"
		13897	},
		13898	"----------\n" +
		13899	"1. ERROR in DoWhileBug.java (at line 6)\n" +
		13900	" if ((o2 = o1) == null) break;\n" +
		13901	" ^^^^^^^^^\n" +
		13902	"Redundant null check: The variable o2 can only be null at this location\n" +
		13903	"----------\n");
		13904	}
		13905
13906	// Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
13907	// in this case considering o1 as unknown is correct
13908	public void testBug336428c() {
13909	if (this.complianceLevel >= ClassFileConstants.JDK1_5) {
13910	this.runConformTest(
13911	new String[] {
13912	"DoWhileBug.java",
13913	"public class DoWhileBug {\n" +
13914	" void test(boolean b1, Object o1) {\n" +
13915	" Object o2 = null;\n" +
13916	" do {\n" +
13917	" if ((o2 = o1) == null) break;\n" +
13918	" } while (true);\n" +
13919	" }\n" +
13920	"}"
13921	},
13922	"");
13923	}
13924	}
13925
13926	// Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
13927	// one more if-statement triggers the expected warnings
13928	public void testBug336428d() {
13929	this.runNegativeTest(
13930	new String[] {
13931	"DoWhileBug.java",
13932	"public class DoWhileBug {\n" +
13933	" void test(boolean b1) {\n" +
13934	" Object o1 = null;\n" +
13935	" Object o2 = null;\n" +
13936	" do {\n" +
13937	" if (b1)\n" +
13938	" o1 = null;\n" +
13939	" if ((o2 = o1) == null) break;\n" +
13940	" } while (true);\n" +
13941	" }\n" +
13942	"}"
13943	},
13944	"----------\n" +
13945	"1. ERROR in DoWhileBug.java (at line 7)\n" +
13946	" o1 = null;\n" +
13947	" ^^\n" +
13948	"Redundant assignment: The variable o1 can only be null at this location\n" +
13949	"----------\n" +
13950	"2. ERROR in DoWhileBug.java (at line 8)\n" +
13951	" if ((o2 = o1) == null) break;\n" +
13952	" ^^^^^^^^^\n" +
13953	"Redundant null check: The variable o2 can only be null at this location\n" +
13954	"----------\n");
13955	}
13956
13957	// Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
13958	// same analysis, but assert instead of if suppresses the warning
13959	public void testBug336428e() {
13960	if (this.complianceLevel >= ClassFileConstants.JDK1_5) {
13961	this.runNegativeTest(
13962	new String[] {
13963	"DoWhileBug.java",
13964	"public class DoWhileBug {\n" +
13965	" void test(boolean b1) {\n" +
13966	" Object o1 = null;\n" +
13967	" Object o2 = null;\n" +
13968	" do {\n" +
13969	" if (b1)\n" +
13970	" o1 = null;\n" +
13971	" assert (o2 = o1) == null : \"bug\";\n" +
13972	" } while (true);\n" +
13973	" }\n" +
13974	"}"
13975	},
13976	"----------\n" +
13977	"1. ERROR in DoWhileBug.java (at line 7)\n" +
13978	" o1 = null;\n" +
13979	" ^^\n" +
13980	"Redundant assignment: The variable o1 can only be null at this location\n" +
13981	"----------\n");
13982	}
13983	}
13984
13836	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=332838	13985	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=332838
13837	// Null info of assert statements should not affect flow info	13986	// Null info of assert statements should not affect flow info
13838	// when CompilerOptions.OPTION_IncludeNullInfoFromAsserts is disabled.	13987	// when CompilerOptions.OPTION_IncludeNullInfoFromAsserts is disabled.

Return to bug 336428

Lines 7-12 Link Here

(-)compiler/org/eclipse/jdt/internal/compiler/flow/LoopingFlowContext.java (-5 / +13 lines)
7	*	7	*
8	* Contributors:	8	* Contributors:
9	* IBM Corporation - initial API and implementation	9	* IBM Corporation - initial API and implementation
		10	* Stephan Herrmann - contribution for Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
10	*******************************************************************************/	11	*******************************************************************************/
11	package org.eclipse.jdt.internal.compiler.flow;	12	package org.eclipse.jdt.internal.compiler.flow;
12		13
Lines 525-535 Link Here
525	if ((this.tagBits & FlowContext.HIDE_NULL_COMPARISON_WARNING) == 0) {	526	if ((this.tagBits & FlowContext.HIDE_NULL_COMPARISON_WARNING) == 0) {
526	recordNullReference(local, reference, checkType);	527	recordNullReference(local, reference, checkType);
527	}	528	}
528	} else if (! flowInfo.cannotBeDefinitelyNullOrNonNull(local)) {	529	} else if (flowInfo.cannotBeDefinitelyNullOrNonNull(local)) {
529	if (flowInfo.isPotentiallyNonNull(local)) {	530	return; // no reason to complain, since there is definitely some uncertainty making the comparison relevant.
530	recordNullReference(local, reference, CAN_ONLY_NON_NULL \| checkType & CONTEXT_MASK);	531	} else {
531	} else {	532	if ((this.tagBits & FlowContext.HIDE_NULL_COMPARISON_WARNING) == 0) {
532	if ((this.tagBits & FlowContext.HIDE_NULL_COMPARISON_WARNING) == 0) {	533	// note: pot non-null & pot null is already captured by cannotBeDefinitelyNullOrNonNull()
		534	if (flowInfo.isPotentiallyNonNull(local)) {
		535	// knowing 'local' can be non-null, we're only interested in seeing whether it can only be non-null
		536	recordNullReference(local, reference, CAN_ONLY_NON_NULL \| checkType & CONTEXT_MASK);
		537	} else if (flowInfo.isPotentiallyNull(local)) {
		538	// knowing 'local' can be null, we're only interested in seeing whether it can only be null
		539	recordNullReference(local, reference, CAN_ONLY_NULL \| checkType & CONTEXT_MASK);
		540	} else {
533	recordNullReference(local, reference, checkType);	541	recordNullReference(local, reference, checkType);
534	}	542	}
535	}	543	}