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fix: remove unused imports after deleting a method argument #5710

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fix: remove unused imports after deleting a method argument #5710

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ead5faa
fix: remove imports after removing a method argument
pdelagrave Jul 4, 2025
42eff47
Slight polish
timtebeek Jul 5, 2025
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129 changes: 129 additions & 0 deletions rewrite-java-test/src/test/java/org/openrewrite/java/DeleteMethodArgumentTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,8 @@ public static void foo(int n1, int n2) {}
public static void foo(int n1, int n2, int n3) {}
public B() {}
public B(int n) {}
public static void foo(String s) {}
public static void foo(java.util.List<?> l) {}
}
""";

Expand Down Expand Up @@ -125,4 +127,131 @@ void deleteFirstArgument() {
)
);
}

@Test
void deleteNullArgument() {
rewriteRun(
spec -> spec.recipe(new DeleteMethodArgument("B foo(String)", 0)),
java(
"public class A {{ B.foo(null); }}",
"public class A {{ B.foo(); }}"
)
);
}

@Test
void removeUnusedImportOfGenericType() {
rewriteRun(
spec -> spec.recipes(new DeleteMethodArgument("B foo(java.util.List)", 0)),
java(
"""
import java.util.ArrayList;

class A {{ B.foo(new ArrayList<>()); }}
""",
"""
class A {{ B.foo(); }}
"""
)
);
}

@Test
void removeUnusedImportOfClassOfStaticMethodWithoutAStaticImport() {
rewriteRun(
spec -> spec.recipes(new DeleteMethodArgument("B foo(java.util.List)", 0)),
java(
"""
import java.util.Collections;

class A {{ B.foo(Collections.emptyList()); }}
""",
"""
class A {{ B.foo(); }}
"""
)
);
}

@Test
void removeUnusedStaticMethodImport() {
rewriteRun(
spec -> spec.recipes(new DeleteMethodArgument("B foo(int)", 0)),
java(
"""
import static java.lang.Math.max;

class A {{ B.foo(max(1,2)); }}
""",
"""
class A {{ B.foo(); }}
"""
)
);
}

@Test
void removeUnusedStaticFieldImport() {
rewriteRun(
spec -> spec.recipes(new DeleteMethodArgument("B foo(int)", 0)),
java(
"""
import static java.lang.Integer.MAX_VALUE;

class A {{ B.foo(MAX_VALUE); }}
""",
"""
class A {{ B.foo(); }}
"""
)
);
}


@Test
void removeUnusedImportOfInnerClass() {
rewriteRun(
spec -> spec.recipes(new DeleteMethodArgument("B foo(java.util.List)", 0)),
java(
"""
import java.util.AbstractMap.SimpleEntry;
import java.util.List;

class A {{
B.foo(List.of(new SimpleEntry<>("a", "b")));
}}
""",
"""
class A {{
B.foo();
}}
"""
)
);
}

@Test
void removeUnusedImportWithLambda() {
rewriteRun(
spec -> spec.recipes(new DeleteMethodArgument("B foo(java.util.List)", 0)),
java(
"""
import java.math.BigInteger;
import java.util.stream.Collectors;
import java.util.stream.Stream;

class A {{
B.foo(Stream.of("23").map(s -> {
return new BigInteger(s).toString();
}).collect(Collectors.toList()));
}}
""",
"""
class A {{
B.foo();
}}
"""
)
);
}
}
47 changes: 39 additions & 8 deletions rewrite-java/src/main/java/org/openrewrite/java/DeleteMethodArgument.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,14 +16,18 @@
package org.openrewrite.java;

import lombok.EqualsAndHashCode;
import lombok.RequiredArgsConstructor;
import lombok.Value;
import org.jspecify.annotations.Nullable;
import org.openrewrite.*;
import org.openrewrite.java.search.UsesMethod;
import org.openrewrite.java.tree.*;
import org.openrewrite.marker.Markers;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import static java.util.Collections.singletonList;
import static org.openrewrite.Tree.randomId;
Expand Down Expand Up @@ -75,16 +79,14 @@ public Validated<Object> validate() {

@Override
public TreeVisitor<?, ExecutionContext> getVisitor() {
return Preconditions.check(new UsesMethod<>(methodPattern), new DeleteMethodArgumentVisitor(new MethodMatcher(methodPattern)));
MethodMatcher methodMatcher = new MethodMatcher(methodPattern);
return Preconditions.check(new UsesMethod<>(methodMatcher), new DeleteMethodArgumentVisitor(methodMatcher));
}

@RequiredArgsConstructor
private class DeleteMethodArgumentVisitor extends JavaIsoVisitor<ExecutionContext> {
private final MethodMatcher methodMatcher;

public DeleteMethodArgumentVisitor(MethodMatcher methodMatcher) {
this.methodMatcher = methodMatcher;
}

@Override
public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, ExecutionContext ctx) {
J.MethodInvocation m = super.visitMethodInvocation(method, ctx);
Expand All @@ -101,8 +103,8 @@ private MethodCall visitMethodCall(MethodCall methodCall) {
MethodCall m = methodCall;
List<Expression> originalArgs = m.getArguments();
if (methodMatcher.matches(m) && originalArgs.stream()
.filter(a -> !(a instanceof J.Empty))
.count() >= argumentIndex + 1) {
.filter(a -> !(a instanceof J.Empty))
.count() >= argumentIndex + 1) {
List<Expression> args = new ArrayList<>(originalArgs);

Expression removed = args.remove(argumentIndex);
Expand All @@ -111,9 +113,38 @@ private MethodCall visitMethodCall(MethodCall methodCall) {
} else if (argumentIndex == 0) {
args.set(0, args.get(0).withPrefix(removed.getPrefix()));
}

m = m.withArguments(args);

// Remove imports of types used in the removed argument
new JavaIsoVisitor<Set<String>>() {
@Override
public @Nullable JavaType visitType(@Nullable JavaType javaType, Set<String> types) {
if (javaType instanceof JavaType.Class) {
JavaType.Class type = (JavaType.Class) javaType;
if (!"java.lang".equals(type.getPackageName())) {
types.add(type.getFullyQualifiedName());
}
} else if (javaType instanceof JavaType.Variable) {
JavaType.Variable variable = (JavaType.Variable) javaType;
if (variable.hasFlags(Flag.Static) && variable.getOwner() instanceof JavaType.Class) {
JavaType.Class owner = (JavaType.Class) variable.getOwner();
types.add(owner.getFullyQualifiedName() + "." + variable.getName());
}
}
return super.visitType(javaType, types);
}

@Override
public J.MethodInvocation visitMethodInvocation(J.MethodInvocation mi, Set<String> strings) {
if (mi.getMethodType() != null && mi.getMethodType().hasFlags(Flag.Static) && mi.getSelect() == null) {
JavaType.FullyQualified receiverType = mi.getMethodType().getDeclaringType();
strings.add(receiverType.getFullyQualifiedName() + "." + mi.getSimpleName());
}
return super.visitMethodInvocation(mi, strings);
}
}.reduce(removed, new HashSet<>()).forEach(this::maybeRemoveImport);

// Update the method types
JavaType.Method methodType = m.getMethodType();
if (methodType != null) {
List<String> parameterNames = new ArrayList<>(methodType.getParameterNames());
Expand Down