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fix: avoid reflective help text formatting #443

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fix: avoid reflective help text formatting #443

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978529b
fix: avoid reflective help formatting
efegokdemir Sep 25, 2026
94e3b26
style: order DescribeMojoTest assertions
efegokdemir Oct 13, 2026
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100 changes: 64 additions & 36 deletions src/main/java/org/apache/maven/plugins/help/DescribeMojo.java
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Original file line number Diff line number Diff line change
Expand Up @@ -22,8 +22,6 @@

import java.io.File;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
Expand Down Expand Up @@ -733,48 +731,78 @@ private boolean describeCommand(StringBuilder descriptionBuffer) throws MojoExec
}

/**
* Invoke the following private method
* <code>HelpMojo#toLines(String, int, int, int)</code>
* Splits and wraps display text without depending on the generated help mojo implementation.
*
* @param text The text to split into lines, must not be <code>null</code>.
* @param indent The base indentation level of each line, must not be negative.
* @param indentSize The size of each indentation, must not be negative.
* @param lineLength The length of the line, must not be negative.
* @return The sequence of display lines, never <code>null</code>.
* @throws MojoFailureException if any can not invoke the method
* @throws MojoExecutionException if no line was found for <code>text</code>
* @param text the text to split
* @param indent the base indentation level of each line
* @param indentSize the size of each indentation
* @param lineLength the maximum line length
* @return the display lines
* @throws MojoFailureException if the requested indentation cannot be represented safely
*/
private static List<String> toLines(String text, int indent, int indentSize, int lineLength)
throws MojoFailureException, MojoExecutionException {
try {
Method m =
HelpMojo.class.getDeclaredMethod("toLines", String.class, Integer.TYPE, Integer.TYPE, Integer.TYPE);
m.setAccessible(true);
@SuppressWarnings("unchecked")
List<String> output = (List<String>) m.invoke(HelpMojo.class, text, indent, indentSize, lineLength);

if (output == null) {
throw new MojoExecutionException("No output was specified.");
throws MojoFailureException {
List<String> lines = new ArrayList<>();
String ind = repeat("\t", indent);

for (String plainLine : text.split("(\r\n)|(\r)|(\n)")) {
addLines(lines, ind + plainLine, indentSize, lineLength);
}
return lines;
}

private static void addLines(List<String> lines, String line, int indentSize, int lineLength)
throws MojoFailureException {
int lineIndent = getIndentLevel(line);
StringBuilder buf = new StringBuilder(256);

for (String token : line.split(" +")) {
if (buf.length() > 0) {
if (buf.length() + token.length() >= lineLength) {
lines.add(buf.toString());
buf.setLength(0);
buf.append(repeat(" ", Math.multiplyExact(lineIndent, indentSize)));
} else {
buf.append(' ');
}
}
for (int j = 0; j < token.length(); j++) {
char c = token.charAt(j);
if (c == '\t') {
buf.append(repeat(" ", indentSize - buf.length() % indentSize));
} else if (c == '\u00A0') {
buf.append(' ');
} else {
buf.append(c);
}
}
}
lines.add(buf.toString());
}

return output;
} catch (SecurityException e) {
throw new MojoFailureException("SecurityException: " + e.getMessage());
} catch (IllegalArgumentException e) {
throw new MojoFailureException("IllegalArgumentException: " + e.getMessage());
} catch (NoSuchMethodException e) {
throw new MojoFailureException("NoSuchMethodException: " + e.getMessage());
} catch (IllegalAccessException e) {
throw new MojoFailureException("IllegalAccessException: " + e.getMessage());
} catch (InvocationTargetException e) {
Throwable cause = e.getCause();

if (cause instanceof NegativeArraySizeException) {
throw new MojoFailureException("NegativeArraySizeException: " + cause.getMessage());
private static int getIndentLevel(String line) {
int level = 0;
for (int i = 0; i < line.length() && line.charAt(i) == '\t'; i++) {
level++;
}
for (int i = level + 1; i <= level + 4 && i < line.length(); i++) {
if (line.charAt(i) == '\t') {
level++;
break;
}
}
return level;
}

throw new MojoFailureException("InvocationTargetException: " + e.getMessage());
private static String repeat(String str, int repeat) throws MojoFailureException {
if (repeat < 0 || ((long) repeat * str.length()) >= Integer.MAX_VALUE) {
throw new MojoFailureException("Requested indentation is too large");
}
StringBuilder result = new StringBuilder((int) ((long) repeat * str.length()));
for (int i = 0; i < repeat; i++) {
result.append(str);
}
return result.toString();
}

/**
Expand Down
13 changes: 13 additions & 0 deletions src/test/java/org/apache/maven/plugins/help/DescribeMojoTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@
import org.apache.maven.model.Plugin;
import org.apache.maven.plugin.MavenPluginManager;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.apache.maven.plugin.descriptor.MojoDescriptor;
import org.apache.maven.plugin.descriptor.Parameter;
import org.apache.maven.plugin.descriptor.PluginDescriptor;
Expand All @@ -51,6 +52,7 @@
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.junit.jupiter.api.Assertions.fail;
import static org.mockito.ArgumentMatchers.any;
Expand All @@ -76,6 +78,17 @@ void testGetExpressionsRoot()
toLines.invoke(null, "", 2, 2, 80);
}

@Test
void testToLinesRejectsOverflowingIndentation() throws Exception {
Method toLines = DescribeMojo.class.getDeclaredMethod("toLines", String.class, int.class, int.class, int.class);
toLines.setAccessible(true);

InvocationTargetException exception = assertThrows(
InvocationTargetException.class, () -> toLines.invoke(null, "text", Integer.MAX_VALUE, 2, 80));

assertTrue(exception.getCause() instanceof MojoFailureException);
}

@Test
void testValidExpression() throws Exception {
StringBuilder sb = new StringBuilder();
Expand Down