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Java: Highlight switch expressions that don't produce the result on some execution path (IDEA-202621)

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This commit is contained in:
Pavel Dolgov
2018-11-22 16:13:48 +03:00
parent 8d6d4f9758
commit 153535ef9a
7 changed files with 247 additions and 0 deletions
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java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightUtil.java
+31
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@@ -51,6 +51,7 @@ import com.intellij.util.containers.MultiMap;
import com.intellij.util.containers.hash.HashSet;
import com.intellij.util.ui.UIUtil;
import com.intellij.xml.util.XmlStringUtil;
import com.siyeh.ig.psiutils.ControlFlowUtils;
import gnu.trove.THashMap;
import org.jetbrains.annotations.Contract;
import org.jetbrains.annotations.NotNull;
@@ -2017,6 +2018,36 @@ public class HighlightUtil extends HighlightUtilBase {
return results;
}
@Nullable
static Collection<HighlightInfo> checkSwitchExpressionHasResult(@NotNull PsiSwitchExpression switchExpression) {
PsiCodeBlock switchBody = switchExpression.getBody();
if (switchBody != null) {
PsiStatement lastStatement = PsiTreeUtil.getPrevSiblingOfType(switchBody.getRBrace(), PsiStatement.class);
if (lastStatement instanceof PsiSwitchLabeledRuleStatement) {
Collection<HighlightInfo> results = new ArrayList<>();
for (PsiSwitchLabeledRuleStatement rule = (PsiSwitchLabeledRuleStatement)lastStatement;
rule != null;
rule = PsiTreeUtil.getPrevSiblingOfType(rule, PsiSwitchLabeledRuleStatement.class)) {
PsiStatement ruleBody = rule.getBody();
// the expression and throw statements are fine, only the block statement could be an issue
if (ruleBody instanceof PsiBlockStatement && ControlFlowUtils.statementMayCompleteNormally(ruleBody)) {
PsiElement target = ObjectUtils.notNull(ObjectUtils.tryCast(rule.getFirstChild(), PsiKeyword.class), rule);
results.add(HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(target)
.descriptionAndTooltip(JavaErrorMessages.message("switch.expr.rule.should.produce.result")).create());
}
}
return results;
}
// previous statements may have no result as well but in that case they fall through to the last one which needs to be checked anyway
if (lastStatement != null && ControlFlowUtils.statementMayCompleteNormally(lastStatement)) {
PsiElement target = ObjectUtils.notNull(ObjectUtils.tryCast(switchExpression.getFirstChild(), PsiKeyword.class), switchExpression);
return Collections.singletonList(HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(target)
.descriptionAndTooltip(JavaErrorMessages.message("switch.expr.should.produce.result")).create());
}
}
return null;
}
/**
* see JLS 8.3.2.3
java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightVisitorImpl.java
+1
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@@ -1608,6 +1608,7 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
if (!myHolder.hasErrorResults()) myHolder.add(checkFeature(expression, Feature.SWITCH_EXPRESSION));
checkSwitchBlock(expression);
if (!myHolder.hasErrorResults()) myHolder.addAll(HighlightUtil.checkSwitchExpressionReturnTypeCompatible(expression));
if (!myHolder.hasErrorResults()) myHolder.addAll(HighlightUtil.checkSwitchExpressionHasResult(expression));
}
private void checkSwitchBlock(PsiSwitchBlock switchBlock) {
java/java-psi-impl/src/messages/JavaErrorMessages.properties
+2
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@@ -269,6 +269,8 @@ duplicate.switch.label=Duplicate label ''{0}''
switch.colon.expected.after.case.label=':' expected
switch.expr.empty='switch' expression does not have any case clauses
switch.expr.incomplete='switch' expression does not cover all possible input values
switch.expr.should.produce.result=Switch expression should produce result in all execution paths
switch.expr.rule.should.produce.result=Switch expression rule should produce result in all execution paths
illegal.forward.reference=Illegal forward reference
illegal.self.reference=Illegal self reference
java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting12/EnhancedSwitchDefinitelyAssigned.java
+39
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@@ -177,4 +177,43 @@ class C {
};
System.out.println(<error descr="Variable 'n' might not have been initialized">n</error>);
}
void switchExpressionAssignedInFinally(int n) {
String s;
try {
} finally {
s = switch (n) {
case -1 -> throw new RuntimeException();
case 0 -> "a";
default -> "b";
};
}
System.out.println(s);
}
void allSwitchRulesAssignInFinally(int n) {
String s;
try {
} finally {
String string = switch (n) {
case -1 -> throw new RuntimeException();
case 0 -> s = "a";
default -> { break s = "b"; }
};
}
System.out.println(s);
}
void notAllSwitchRulesAssignInFinally(int n) {
String s;
try {
} finally {
String t = switch (n) {
case -1 -> throw new RuntimeException();
case 0 -> s = "a";
default -> "b";
};
}
System.out.println(<error descr="Variable 's' might not have been initialized">s</error>);
}
}
java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting12/EnhancedSwitchUnreachable.java
+24
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@@ -86,6 +86,30 @@ class C {
<error descr="Unreachable statement">System.out.println();</error>
}
void switchExpressionUnreachableInFinally(int n) {
String s;
try {
} finally {
return;
s = <error descr="Unreachable statement">switch</error> (n) {
case 0 -> "a";
default -> "b";
};
}
}
void switchExpressionReachableInFinally(int n) {
String s;
try {
return;
} finally {
s = switch (n) {
case 0 -> "a";
default -> "b";
};
}
}
static class SwitchExpressionReturnedFromTry {
int foo(String s) throws Exception {
try {
java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting12/SwitchExpressionHasResult.java
+149
View File
@@ -0,0 +1,149 @@
class C {
void defaultBranchHasNoResult(int n) {
String s = <error descr="Switch expression should produce result in all execution paths">switch</error> (n) {
default:
};
}
void defaultRuleHasNoResult(int n) {
String s = switch (n) {
<error descr="Switch expression rule should produce result in all execution paths">default</error> -> {}
};
}
void defaultBranchSometimesHasNoResult(int n, boolean b) {
String s = <error descr="Switch expression should produce result in all execution paths">switch</error> (n) {
default: {
if (b) break "";
}
};
}
void defaultRuleSometimesHasNoResult(int n, boolean b) {
String s = switch (n) {
<error descr="Switch expression rule should produce result in all execution paths">default</error> -> {
if (b) break "";
}
};
}
void defaultBranchAlwaysThrows(int n) {
String s = switch (n) {
default: throw new RuntimeException();
};
}
void defaultRuleAlwaysThrows(int n) {
String s = switch (n) {
default -> throw new RuntimeException();
};
}
void defaultBranchSometimesThrows(int n, boolean b) {
String s = switch (n) {
default:
if (b) throw new RuntimeException();
break "";
};
}
void defaultRuleSometimesThrows(int n, boolean b) {
String s = switch (n) {
default -> {
if (b) throw new RuntimeException();
break "";
}
};
}
void defaultBranchHasManyResults(int n, int k) {
String s = switch (n) {
default: {
if (k < n) break "a";
if (k > n) break "b";
break "c";
}
};
}
void defaultRuleHasManyResults(int n, int k) {
String s = switch (n) {
default -> {
if (k < n) break "a";
if (k > n) break "b";
break "c";
}
};
}
void oneOfBranchesHasNoResult(int n) {
String s = <error descr="Switch expression should produce result in all execution paths">switch</error> (n) {
case 0: break "";
default:
};
}
void oneOfRulesHasNoResult(int n) {
String s = switch (n) {
case 0 -> "";
<error descr="Switch expression rule should produce result in all execution paths">default</error> -> {
}
};
}
void allBranchesHaveNoResult(int n) {
String s = <error descr="Switch expression should produce result in all execution paths">switch</error> (n) {
case 0:
default:
};
}
void allRulesHaveNoResult(int n) {
String s = switch (n) {
<error descr="Switch expression rule should produce result in all execution paths">case</error> 0 -> {
}
<error descr="Switch expression rule should produce result in all execution paths">default</error> -> {
}
};
}
void allBranchesDoHaveResult(int n) {
String s = switch (n) {
case -1: throw new RuntimeException();
case 0: break "a";
default: break "b";
};
}
void allRulesDoHaveResult(int n) {
String s = switch (n) {
case -1 -> throw new RuntimeException();
case 0 -> "a";
default -> "b";
};
}
void allBranchesDoHaveResultInFinally(int n) {
String s;
try {
} finally {
s = switch (n) {
case -1: throw new RuntimeException();
case 0: break "a";
default: break "b";
};
}
}
void allRulesDoHaveResultInFinally(int n) {
String s;
try {
} finally {
s = switch (n) {
case -1 -> throw new RuntimeException();
case 0 -> "a";
default -> "b";
};
}
}
}
java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/LightJava12HighlightingTest.kt
+1
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@@ -15,6 +15,7 @@ class LightJava12HighlightingTest : LightCodeInsightFixtureTestCase() {
fun testSimpleInferenceCases() = doTest()
fun testEnhancedSwitchDefinitelyAssigned() = doTest()
fun testEnhancedSwitchUnreachable() = doTest()
fun testSwitchExpressionHasResult() = doTest()
private fun doTest() {
myFixture.configureByFile(getTestName(false) + ".java")