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Fix NPE in VarWithPrimitive when lambda parameters have inferred primitive types #5873

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Fix NPE in VarWithPrimitive when lambda parameters have inferred primitive types #5873

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4 changes: 2 additions & 2 deletions check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1863,10 +1863,10 @@ public static String castTree(ExpressionTree expressionTree, String toType, Visi
public static Optional<SuggestedFix> replaceVariableType(
VariableTree tree, String replacementType, VisitorState state) {
Tree type = tree.getType();
if (hasExplicitSource(type, state)) {
if (type != null && hasExplicitSource(type, state)) {
return Optional.of(SuggestedFix.replace(type, replacementType));
}
int pos = getStartPosition(type);
int pos = type != null ? getStartPosition(type) : Position.NOPOS;
if (pos == Position.NOPOS) {
pos = getStartPosition(tree);
}
Expand Down
229 changes: 229 additions & 0 deletions core/src/test/java/com/google/errorprone/bugpatterns/VarWithPrimitiveTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,10 @@

package com.google.errorprone.bugpatterns;

import static com.google.common.truth.TruthJUnit.assume;

import com.google.errorprone.BugCheckerRefactoringTestHelper;
import com.google.errorprone.CompilationTestHelper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
Expand All @@ -27,6 +30,9 @@ public final class VarWithPrimitiveTest {
private final BugCheckerRefactoringTestHelper refactoringHelper =
BugCheckerRefactoringTestHelper.newInstance(VarWithPrimitive.class, getClass());

private final CompilationTestHelper compilationHelper =
CompilationTestHelper.newInstance(VarWithPrimitive.class, getClass());

// from https://openjdk.org/projects/amber/guides/lvti-style-guide#G7
@Test
public void lvtiExamples() {
Expand Down Expand Up @@ -194,6 +200,229 @@ long getAgeAsLong() {
.doTest();
}

@Test
public void enhancedForLoop() {
refactoringHelper
.addInputLines(
"Test.java",
"""
class Test {
void t() {
int[] arr = {1, 2, 3};
for (var x : arr) {
System.out.println(x);
}
}
}
""")
.addOutputLines(
"Test.java",
"""
class Test {
void t() {
int[] arr = {1, 2, 3};
for (int x : arr) {
System.out.println(x);
}
}
}
""")
.doTest();
}

@Test
public void forLoopInitializer() {
refactoringHelper
.addInputLines(
"Test.java",
"""
class Test {
void t() {
for (var i = 0; i < 10; i++) {
System.out.println(i);
}
}
}
""")
.addOutputLines(
"Test.java",
"""
class Test {
void t() {
for (int i = 0; i < 10; i++) {
System.out.println(i);
}
}
}
""")
.doTest();
}

@Test
public void implicitLambdaParameter_noMatch() {
refactoringHelper
.addInputLines(
"Test.java",
"""
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
class Test {
void foo() {
byte[] bar = new byte[6];
Map<Byte, List<Byte>> indicesMap =
IntStream.range(0, 6)
.mapToObj(n -> n)
.collect(
Collectors.groupingBy(
n -> bar[n],
Collectors.mapping(
n -> (byte) n.intValue(), Collectors.toList())));
}
}
""")
.expectUnchanged()
.doTest();
}

@Test
public void varLambdaParam() {
refactoringHelper
.addInputLines(
"Test.java",
"""
import java.util.function.IntUnaryOperator;
class Test {
void t() {
IntUnaryOperator op = (var n) -> n * 2;
}
}
""")
.addOutputLines(
"Test.java",
"""
import java.util.function.IntUnaryOperator;
class Test {
void t() {
IntUnaryOperator op = (int n) -> n * 2;
}
}
""")
.doTest();
}

@Test
public void annotatedVarLambdaParam() {
refactoringHelper
.addInputLines("A.java", "@interface A { int var() default 0; }")
.expectUnchanged()
.addInputLines(
"Test.java",
"""
import java.util.function.IntUnaryOperator;
class Test {
void t() {
IntUnaryOperator op = (@A(var = 0) var n) -> n * 2;
}
}
""")
.addOutputLines(
"Test.java",
"""
import java.util.function.IntUnaryOperator;
class Test {
void t() {
IntUnaryOperator op = (@A(var = 0) int n) -> n * 2;
}
}
""")
.doTest();
}

@Test
public void annotatedVarLocalVariable_beforeJdk27() {
// Before JDK 27 there is no AST node for the var type, so the token scan finds two 'var'
// tokens (@A(var=0) attribute + type keyword) and safely returns no fix.
assume().that(Runtime.version().feature()).isLessThan(27);
refactoringHelper
.addInputLines("A.java", "@interface A { int var() default 0; }")
.expectUnchanged()
.addInputLines(
"Test.java",
"""
class Test {
void t() {
@A(var = 0) var n = 5;
}
}
""")
.expectUnchanged()
.doTest();
}

@Test
public void annotatedVarLocalVariable_jdk27AndAbove() {
// On JDK 27+ there is an AST node for the var type with source positions, so hasExplicitSource
// returns true and the replacement targets the type keyword directly, preserving the
// annotation.
assume().that(Runtime.version().feature()).isAtLeast(27);
refactoringHelper
.addInputLines("A.java", "@interface A { int var() default 0; }")
.expectUnchanged()
.addInputLines(
"Test.java",
"""
class Test {
void t() {
@A(var = 0) var n = 5;
}
}
""")
.addOutputLines(
"Test.java",
"""
class Test {
void t() {
@A(var = 0) int n = 5;
}
}
""")
.doTest();
}

@Test
public void multiParamImplicitLambda_noMatch() {
compilationHelper
.addSourceLines(
"Test.java",
"""
import java.util.function.IntBinaryOperator;
class Test {
void t() {
IntBinaryOperator op = (a, b) -> a + b;
}
}
""")
.doTest();
}

@Test
public void explicitLambdaParam_noMatch() {
compilationHelper
.addSourceLines(
"Test.java",
"""
import java.util.function.IntUnaryOperator;
class Test {
void t() {
IntUnaryOperator op = (int n) -> n * 2;
}
}
""")
.doTest();
}

@Test
public void explicitType() {
refactoringHelper
Expand Down
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