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Rename variables if the name matches class name #5454

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8551095
Rename variables if the name matches class name
radoslaw-panuszewski May 19, 2025
8e132e2
Prevent variable name conflicts; support unicode characters
radoslaw-panuszewski May 20, 2025
0820d5c
Fix tests in rewrite-kotlin
radoslaw-panuszewski May 20, 2025
f2f61a6
Add test verifying that random variables with matching name are not r…
radoslaw-panuszewski May 20, 2025
5bad96a
Use 𐐅/𐐭 instead of Ą/ą in test since Ą is in BMP
radoslaw-panuszewski May 21, 2025
9c4ea8f
Revert unicode characters handling in decapitalize method as it seems…
radoslaw-panuszewski May 21, 2025
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10 changes: 0 additions & 10 deletions rewrite-core/src/main/java/org/openrewrite/internal/StringUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -732,14 +732,4 @@ public static boolean containsWhitespace(String s) {

return false;
}

/**
* @return string with first character changed to lowercase (or empty string)
*/
public static String decapitalize(@Nullable String string) {
if (string != null && !string.isEmpty()) {
return Character.toLowerCase(string.charAt(0)) + string.substring(1);
}
return "";
}
}
86 changes: 86 additions & 0 deletions rewrite-java-test/src/test/java/org/openrewrite/java/ChangeTypeTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1630,6 +1630,92 @@ public class Test {
);
}

@Test
void updateMethodTypeWithUnicodeCharacter() {
rewriteRun(
spec -> spec.recipe(new ChangeType("a.Ą1", "a.Ą2", false)),
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Since Ą is in the BMP, this test should pass with the old code as well. In order to really see the change going from characters to codepoints, you probably need something like 𐐓 (\uD801\uDC13).

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@radoslaw-panuszewski radoslaw-panuszewski May 21, 2025 •
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I tried changing Ą/ą to 𐐅/𐐭 but I encountered strange issues from unrelated parts of the code (like import statement started disappearing). I've spent some time debugging it but eventually gave up as it seems to be a broader issue and fixing it is out of scope of this PR.

I reverted the code of decapitalize method to the previous version and removed the test case with special characters. All of my experiments are in the git history in case someone would like to continue the fight from there 😄

java(
"""
package a;
public class Ą1 {
}
""",
"""
package a;
public class Ą2 {
}
"""
),
java(
"""
package org.foo;

import a.Ą1;

public class Example {
public Ą1 method(Ą1 ą1) {
return ą1;
}
}
""",
"""
package org.foo;

import a.Ą2;

public class Example {
public Ą2 method(Ą2 ą2) {
return ą2;
}
}
"""
)
);
}

@Test
void doNotRenameRandomVariablesMatchingClassName() {
rewriteRun(
spec -> spec.recipe(new ChangeType("a.A1", "a.A2", false)),
java(
"""
package a;
public class A1 {
}
""",
"""
package a;
public class A2 {
}
"""
),
java(
"""
package org.foo;

import a.A1;

public class Example {
public String method(A1 a, String a1) {
return a1;
}
}
""",
"""
package org.foo;

import a.A2;

public class Example {
public String method(A2 a, String a1) {
return a1;
}
}
"""
)
);
}

@Test
void updateVariableType() {
rewriteRun(
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23 changes: 21 additions & 2 deletions rewrite-java/src/main/java/org/openrewrite/java/ChangeType.java
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
import org.jspecify.annotations.Nullable;
import org.openrewrite.*;
import org.openrewrite.internal.ListUtils;
import org.openrewrite.java.VariableNameUtils.GenerationStrategy;
import org.openrewrite.java.search.UsesType;
import org.openrewrite.java.tree.*;
import org.openrewrite.marker.Markers;
Expand All @@ -32,7 +33,6 @@
import java.util.concurrent.atomic.AtomicBoolean;

import static java.util.Objects.requireNonNull;
import static org.openrewrite.internal.StringUtils.decapitalize;

@Value
@EqualsAndHashCode(callSuper = false)
Expand Down Expand Up @@ -372,7 +372,11 @@ public J visitIdentifier(J.Identifier ident, ExecutionContext ctx) {
// Rename variable if it matches class name (starting with a lowercase character)
if (ident.getSimpleName().equals(decapitalize(className))) {
if (targetType instanceof JavaType.FullyQualified) {
String newName = decapitalize(((JavaType.FullyQualified) targetType).getClassName());
String newName = VariableNameUtils.generateVariableName(
decapitalize(((JavaType.FullyQualified) targetType).getClassName()),
getCursor(),
GenerationStrategy.INCREMENT_NUMBER
);

ident = ident.withSimpleName(newName);

Expand Down Expand Up @@ -801,4 +805,19 @@ private static boolean hasSameFQN(J.Import import_, JavaType targetType) {

return fqn != null && fqn.equals(curFqn);
}

private static String decapitalize(String string) {
if (!string.isEmpty()) {
int firstCodePoint = string.codePointAt(0);
int firstCodePointLowercase = Character.toLowerCase(firstCodePoint);

if (firstCodePoint != firstCodePointLowercase) {
return new StringBuilder()
.appendCodePoint(firstCodePointLowercase)
.append(string.substring(Character.charCount(firstCodePoint)))
.toString();
}
}
return string;
}
}
6 changes: 3 additions & 3 deletions rewrite-kotlin/src/test/java/org/openrewrite/kotlin/ChangeTypeTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -195,7 +195,7 @@ fun test(original: Original<String>) { }

import x.y.Target

fun test(original: Target<String>) { }
fun test(target: Target<String>) { }
"""
)
);
Expand Down Expand Up @@ -231,7 +231,7 @@ fun test(original: MyAlias<String>) { }

import x.y.Target as MyAlias

fun test(original: MyAlias<String>) { }
fun test(target: MyAlias<String>) { }
"""
)
);
Expand Down Expand Up @@ -263,7 +263,7 @@ fun test(original: a.b.Original<String>) { }

import x.y.Target

fun test(original: Target<String>) { }
fun test(target: Target<String>) { }
"""
)
);
Expand Down