transform RemoveWildCardImports to linter

CHANGES.md

@@ -17,6 +17,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 * Bump default `google-java-format` version to latest `1.24.0` -> `1.28.0`. ([#2345](https://github.com/diffplug/spotless/pull/2345))
 * Bump default `ktlint` version to latest `1.5.0` -> `1.7.1`. ([#2555](https://github.com/diffplug/spotless/pull/2555))
 * Bump default `jackson` version to latest `2.19.2` -> `2.20.0`. ([#2606](https://github.com/diffplug/spotless/pull/2606))
+* Promote `RemoveWildCardImports` to linter ([#2611](https://github.com/diffplug/spotless/pull/2611))
 
 ## [3.3.1] - 2025-07-21
 ### Fixed

lib/src/main/java/com/diffplug/spotless/Lint.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022-2024 DiffPlug
+ * Copyright 2022-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -91,7 +91,7 @@ public ShortcutException(Lint... lints) {
 		private final List<Lint> lints;
 
 		ShortcutException(Collection<Lint> lints) {
-			super(lints.iterator().next().detail);
+			super(lints.iterator().next().toString());
 			this.lints = List.copyOf(lints);
 		}
 

lib/src/main/java/com/diffplug/spotless/generic/LintRegexStep.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2016-2025 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.generic;
+
+import static com.diffplug.spotless.Lint.atLine;
+
+import java.io.File;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.regex.Pattern;
+
+import com.diffplug.spotless.FormatterFunc;
+import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.Lint;
+
+public final class LintRegexStep {
+	// prevent direct instantiation
+	private LintRegexStep() {}
+
+	public static FormatterStep lint(String name, String regex, String error) {
+		Objects.requireNonNull(name, "name");
+		Objects.requireNonNull(regex, "regex");
+		Objects.requireNonNull(error, "error");
+		return FormatterStep.createLazy(name,
+				() -> new State(Pattern.compile(regex, Pattern.UNIX_LINES | Pattern.MULTILINE), error),
+				State::toLinter);
+	}
+
+	private static final class State implements Serializable {
+		private static final long serialVersionUID = 1L;
+
+		private final Pattern regex;
+		private final String replacement;
+
+		State(Pattern regex, String replacement) {
+			this.regex = regex;
+			this.replacement = replacement;
+		}
+
+		FormatterFunc toFormatter() {
+			return raw -> regex.matcher(raw).replaceAll(replacement);
+		}
+
+		FormatterFunc toLinter() {
+			return new FormatterFunc() {
+				@Override
+				public String apply(String raw) {
+					return raw;
+				}
+
+				@Override
+				public List<Lint> lint(String raw, File file) {
+					List<Lint> lints = new ArrayList<>();
+					var matcher = regex.matcher(raw);
+					while (matcher.find()) {
+						int line = 1 + (int) raw.codePoints().limit(matcher.start()).filter(c -> c == '\n').count();
+						lints.add(atLine(line, matcher.group(0), replacement));
+					}
+					return lints;
+				}
+			};
+		}
+	}
+}

lib/src/main/java/com/diffplug/spotless/java/RemoveWildcardImportsStep.java

@@ -16,17 +16,21 @@
 package com.diffplug.spotless.java;
 
 import com.diffplug.spotless.FormatterStep;
-import com.diffplug.spotless.generic.ReplaceRegexStep;
+import com.diffplug.spotless.generic.LintRegexStep;
 
 /** Removes any wildcard import statements. */
 public final class RemoveWildcardImportsStep {
+
+	/**
+	 * Matches lines like 'import foo.*;' or 'import static foo.*;'.
+	 */
+	private static final String REGEX = "(?m)^import\\s+(?:static\\s+)?[^;\\n]*\\*;\\R?";
+	private static final String NAME = "removeWildcardImports";
+	private static final String ERROR = "Do not use wildcard imports (e.g. java.util.*) - replace with specific class imports (e.g. java.util.List) as 'spotlessApply' cannot auto-fix this";
+
 	private RemoveWildcardImportsStep() {}
 
 	public static FormatterStep create() {
-		// Matches lines like 'import foo.*;' or 'import static foo.*;'.
-		return ReplaceRegexStep.create(
-				"removeWildcardImports",
-				"(?m)^import\\s+(?:static\\s+)?[^;\\n]*\\*;\\R?",
-				"");
+		return LintRegexStep.lint(NAME, REGEX, ERROR);
 	}
 }

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/JavaDefaultTargetTest.java

@@ -15,6 +15,9 @@
  */
 package com.diffplug.gradle.spotless;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
 import java.io.IOException;
 
 import org.junit.jupiter.api.Test;
@@ -97,8 +100,17 @@ void removeWildCardImports() throws IOException {
 				"}");
 
 		setFile("test.java").toResource("java/removewildcardimports/JavaCodeWildcardsUnformatted.test");
-		gradleRunner().withArguments("spotlessApply").build();
-		assertFile("test.java").sameAsResource("java/removewildcardimports/JavaCodeWildcardsFormatted.test");
+		gradleRunner().withArguments("spotlessApply").buildAndFail();
+		assertThat(assertThrows(AssertionError.class, () -> assertFile("test.java").sameAsResource("java/removewildcardimports/JavaCodeWildcardsFormatted.test")).getMessage())
+				.contains("Extra content at line 1:")
+				.contains("Extra content at line 3:")
+				.contains("import io.quarkus.maven.dependency.*;")
+				.contains("import static io.quarkus.vertx.web.Route.HttpMethod.*;")
+				.contains("import static org.springframework.web.reactive.function.BodyInserters.*;")
+				.contains("java.util.*")
+				.contains("java.util.Collections.*")
+				.doesNotContain("import mylib.Helper;")
+				.doesNotContain("public class Test {}");
 	}
 
 	/**

plugin-maven/src/test/java/com/diffplug/spotless/maven/java/RemoveWildcardImportsStepTest.java

@@ -15,6 +15,9 @@
  */
 package com.diffplug.spotless.maven.java;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
 import org.junit.jupiter.api.Test;
 
 import com.diffplug.spotless.maven.MavenIntegrationHarness;
@@ -28,6 +31,25 @@ void testRemoveWildcardImports() throws Exception {
 		String path = "src/main/java/test.java";
 		setFile(path).toResource("java/removewildcardimports/JavaCodeWildcardsUnformatted.test");
 		mavenRunner().withArguments("spotless:apply").runNoError();
-		assertFile(path).sameAsResource("java/removewildcardimports/JavaCodeWildcardsFormatted.test");
+		assertThat(assertThrows(AssertionError.class, () -> assertFile(path).sameAsResource("java/removewildcardimports/JavaCodeWildcardsFormatted.test")).getMessage())
+				.contains("Extra content at line 1:")
+				.contains("Extra content at line 3:")
+				.contains("import io.quarkus.maven.dependency.*;")
+				.contains("import static io.quarkus.vertx.web.Route.HttpMethod.*;")
+				.contains("import static org.springframework.web.reactive.function.BodyInserters.*;")
+				.contains("java.util.*")
+				.contains("java.util.Collections.*")
+				.doesNotContain("import mylib.Helper;")
+				.doesNotContain("public class Test {}");
+	}
+
+	@Test
+	void testRemoveWildcardImportsWithNoResult() throws Exception {
+		writePomWithJavaSteps("<removeWildcardImports/>");
+
+		String path = "src/main/java/test.java";
+		setFile(path).toResource("java/removewildcardimports/JavaCodeNoWildcardsUnformatted.test");
+		mavenRunner().withArguments("spotless:apply").runNoError();
+		assertFile(path).sameAsResource("java/removewildcardimports/JavaCodeNoWildcardsFormatted.test");
 	}
 }

testlib/src/main/resources/java/removewildcardimports/JavaCodeNoWildcardsFormatted.test

@@ -0,0 +1,4 @@
+import java.util.List;
+import mylib.Helper;
+
+public class Test {}

testlib/src/main/resources/java/removewildcardimports/JavaCodeNoWildcardsUnformatted.test

@@ -0,0 +1,4 @@
+import java.util.List;
+import mylib.Helper;
+
+public class Test {}

testlib/src/test/java/com/diffplug/spotless/generic/LintRegexStepTest.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2025 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.generic;
+
+import org.junit.jupiter.api.Test;
+
+import com.diffplug.common.base.StringPrinter;
+import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.StepHarness;
+
+class LintRegexStepTest {
+
+	@Test
+	void lint() throws Exception {
+		FormatterStep step = LintRegexStep.lint("regex", "bad", "no bad words");
+		StepHarness.forStep(step)
+				.expectLintsOf(StringPrinter.buildStringFromLines(
+						"bad",
+						"x bad y",
+						"ok"))
+				.toBe("L1 regex(bad) no bad words\nL2 regex(bad) no bad words");
+	}
+}