732: Remove trailing whitespace

src/main/java/org/openrewrite/staticanalysis/RemoveTrailingWhitespace.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Moderne Source Available License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://docs.moderne.io/licensing/moderne-source-available-license
+ * <p>
+ * 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 org.openrewrite.staticanalysis;
+
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.text.PlainText;
+import org.openrewrite.text.PlainTextVisitor;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+@EqualsAndHashCode(callSuper = false)
+@Value
+public class RemoveTrailingWhitespace extends Recipe {
+
+    private static final Pattern TRAILING_WHITESPACE = Pattern.compile("[ \\t]+(?=\\r?\\n|$)", Pattern.MULTILINE);
+
+    @Override
+    public String getDisplayName() {
+        return "Remove trailing whitespace from text files";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Removes trailing whitespace (spaces and tabs) from the end of lines in text files. " +
+               "This helps maintain clean code formatting and prevents unnecessary whitespace in version control.";
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return new PlainTextVisitor<ExecutionContext>() {
+            @Override
+            public PlainText visitText(PlainText text, ExecutionContext ctx) {
+                String content = text.getText();
+                Matcher matcher = TRAILING_WHITESPACE.matcher(content);
+                if (matcher.find()) {
+                    String cleanedContent = matcher.replaceAll("");
+                    return text.withText(cleanedContent);
+                }
+                return text;
+            }
+        };
+    }
+}

src/test/java/org/openrewrite/staticanalysis/RemoveTrailingWhitespaceTest.java

@@ -0,0 +1,202 @@
+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Moderne Source Available License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://docs.moderne.io/licensing/moderne-source-available-license
+ * <p>
+ * 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 org.openrewrite.staticanalysis;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.DocumentExample;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.test.SourceSpecs.text;
+
+class RemoveTrailingWhitespaceTest implements RewriteTest {
+
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec.recipe(new RemoveTrailingWhitespace());
+    }
+
+    @DocumentExample
+    @Test
+    void removeTrailingSpaces() {
+        rewriteRun(
+          text(
+            "Line with trailing spaces   \n" +
+            "Line without trailing spaces\n" +
+            "Another line with spaces  \n",
+            "Line with trailing spaces\n" +
+            "Line without trailing spaces\n" +
+            "Another line with spaces\n"
+          )
+        );
+    }
+
+    @Test
+    void removeTrailingTabs() {
+        rewriteRun(
+          text(
+            "Line with trailing tabs\t\t\n" +
+            "Line without trailing tabs\n" +
+            "Mixed tabs and spaces\t  \n",
+            "Line with trailing tabs\n" +
+            "Line without trailing tabs\n" +
+            "Mixed tabs and spaces\n"
+          )
+        );
+    }
+
+    @Test
+    void removeTrailingWhitespaceFromLastLine() {
+        rewriteRun(
+          text(
+            "First line\n" +
+            "Second line  ",
+            "First line\n" +
+            "Second line"
+          )
+        );
+    }
+
+    @Test
+    void preserveEmptyLines() {
+        rewriteRun(
+          text(
+            "Line 1  \n" +
+            "\n" +
+            "Line 3\t\n" +
+            "\n" +
+            "Line 5",
+            "Line 1\n" +
+            "\n" +
+            "Line 3\n" +
+            "\n" +
+            "Line 5"
+          )
+        );
+    }
+
+    @Test
+    void handleMultipleConsecutiveWhitespaceTypes() {
+        rewriteRun(
+          text(
+            "Spaces then tabs  \t\t\n" +
+            "Tabs then spaces\t\t  \n" +
+            "Mixed whitespace \t \t \n",
+            "Spaces then tabs\n" +
+            "Tabs then spaces\n" +
+            "Mixed whitespace\n"
+          )
+        );
+    }
+
+    @Test
+    void noChangesWhenNoTrailingWhitespace() {
+        rewriteRun(
+          text(
+            "Clean line 1\n" +
+            "Clean line 2\n" +
+            "Clean line 3"
+          )
+        );
+    }
+
+    @Test
+    void handleEmptyFile() {
+        rewriteRun(
+          text("")
+        );
+    }
+
+    @Test
+    void handleLinesWithOnlyWhitespace() {
+        rewriteRun(
+          text(
+            "line with content\n" +
+            "   \n" +
+            "another line",
+            "line with content\n" +
+            "\n" +
+            "another line"
+          )
+        );
+    }
+
+    @Test
+    void preserveIndentationWhitespace() {
+        rewriteRun(
+          text(
+            "    Indented line  \n" +
+            "\tTab indented line\t\n" +
+            "  Mixed indentation\t  ",
+            "    Indented line\n" +
+            "\tTab indented line\n" +
+            "  Mixed indentation"
+          )
+        );
+    }
+
+    @Test
+    void handleWindowsLineEndings() {
+        rewriteRun(
+          text(
+            "Windows line 1  \r\n" +
+            "Windows line 2\t\r\n" +
+            "Windows line 3",
+            "Windows line 1\r\n" +
+            "Windows line 2\r\n" +
+            "Windows line 3"
+          )
+        );
+    }
+
+    @Test
+    void handleMacLineEndings() {
+        rewriteRun(
+          text(
+            "Mac line 1  \r" +
+            "Mac line 2\t\r" +
+            "Mac line 3",
+            "Mac line 1\r" +
+            "Mac line 2\r" +
+            "Mac line 3"
+          )
+        );
+    }
+
+    @Test
+    void handleLargeAmountOfTrailingWhitespace() {
+        StringBuilder input = new StringBuilder();
+        StringBuilder expected = new StringBuilder();
+
+        // Create lines with varying amounts of trailing whitespace
+        for (int i = 1; i <= 10; i++) {
+            input.append("Line ").append(i).repeat(" ", i);
+            expected.append("Line ").append(i);
+
+            if (i < 10) {
+                input.append("\n");
+                expected.append("\n");
+            }
+        }
+
+        rewriteRun(
+          text(
+            input.toString(),
+            expected.toString()
+          )
+        );
+    }
+}