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The following commit(s) were added to refs/heads/master by this push:
new f3e64b3b0 StrBuilder.setLength(int) shrink-branch leaves residual
chars in buffer tail (#1671)
f3e64b3b0 is described below
commit f3e64b3b0e67d7faa0f10b698e08207f972a15b1
Author: Gary Gregory <[email protected]>
AuthorDate: Sun May 24 12:07:24 2026 -0400
StrBuilder.setLength(int) shrink-branch leaves residual chars in buffer
tail (#1671)
* Add ArrayFill.clear(char[], int, int)
* Add ArrayFill.fill(char[], int, int, char)
* StrBuilder.setLength(int) shrink-branch leaves residual chars in buffer
tail
---
.../java/org/apache/commons/lang3/ArrayFill.java | 52 +++++++++++++++++++---
.../org/apache/commons/lang3/text/StrBuilder.java | 35 +++++++++------
.../org/apache/commons/lang3/ArrayFillTest.java | 45 +++++++++++++++++++
.../commons/lang3/text/StrBuilderClearTest.java | 23 ++++++++++
4 files changed, 135 insertions(+), 20 deletions(-)
diff --git a/src/main/java/org/apache/commons/lang3/ArrayFill.java
b/src/main/java/org/apache/commons/lang3/ArrayFill.java
index 7b9617e63..e6b9d95e5 100644
--- a/src/main/java/org/apache/commons/lang3/ArrayFill.java
+++ b/src/main/java/org/apache/commons/lang3/ArrayFill.java
@@ -29,6 +29,22 @@
*/
public final class ArrayFill {
+ /**
+ * Fills and returns the given array, assigning {@code 0} to each element
of the array.
+ * <pre>
+ * ArrayFill.fill(a, (byte) 0);
+ * </pre>
+ *
+ * @param a the array to fill (may be null).
+ * @return the given array.
+ * @see Arrays#fill(byte[],byte)
+ * @see ArrayFill#fill(byte[],byte)
+ * @since 3.21.0
+ */
+ public static byte[] clear(final byte[] a) {
+ return fill(a, (byte) 0);
+ }
+
/**
* Fills and returns the given array, assigning {@code '\0'} to each
element of the array.
* <p>
@@ -50,19 +66,23 @@ public static char[] clear(final char[] a) {
}
/**
- * Fills and returns the given array, assigning {@code 0} to each element
of the array.
+ * Fills and returns the given array, assigning {@code '\0'} to each
element of the array.
+ * <p>
+ * Equivalent to:
+ * </p>
* <pre>
- * ArrayFill.fill(a, (byte) 0);
+ * ArrayFill.fill(a, fromIndex, toIndex, '\0'); // and not '0'!
* </pre>
*
- * @param a the array to fill (may be null).
+ * @param a the array to fill (may be null).
+ * @param fromIndex the index of the first element (inclusive) to be
filled with {@code '\0'}.
+ * @param toIndex the index of the last element (exclusive) to be filled
with {@code '\0'}.
* @return the given array.
- * @see Arrays#fill(byte[],byte)
- * @see ArrayFill#fill(byte[],byte)
+ * @see Arrays#fill(char[], int, int, char)
* @since 3.21.0
*/
- public static byte[] clear(final byte[] a) {
- return fill(a, (byte) 0);
+ public static char[] clear(char[] a, int fromIndex, int toIndex) {
+ return fill(a, fromIndex, toIndex, CharUtils.NUL);
}
/**
@@ -111,6 +131,24 @@ public static char[] fill(final char[] a, final char val) {
return a;
}
+ /**
+ * Fills and returns the given array, assigning the given {@code char}
value to each element of the array.
+ *
+ * @param a the array to fill (may be null).
+ * @param val the value to store in all elements of the array.
+ * @param fromIndex the index of the first element (inclusive) to be
filled with the specified value.
+ * @param toIndex the index of the last element (exclusive) to be filled
with the specified value.
+ * @return the given array.
+ * @see Arrays#fill(char[], int, int, char)
+ * @since 3.21.0
+ */
+ public static char[] fill(char[] a, int fromIndex, int toIndex, char val) {
+ if (a != null) {
+ Arrays.fill(a, fromIndex, toIndex, val);
+ }
+ return a;
+ }
+
/**
* Fills and returns the given array, assigning the given {@code double}
value to each element of the array.
*
diff --git a/src/main/java/org/apache/commons/lang3/text/StrBuilder.java
b/src/main/java/org/apache/commons/lang3/text/StrBuilder.java
index acdf4abf7..aa98cd992 100644
--- a/src/main/java/org/apache/commons/lang3/text/StrBuilder.java
+++ b/src/main/java/org/apache/commons/lang3/text/StrBuilder.java
@@ -26,8 +26,8 @@
import java.util.List;
import java.util.Objects;
+import org.apache.commons.lang3.ArrayFill;
import org.apache.commons.lang3.ArrayUtils;
-import org.apache.commons.lang3.CharUtils;
import org.apache.commons.lang3.ObjectUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Strings;
@@ -1614,7 +1614,7 @@ public char charAt(final int index) {
*/
public StrBuilder clear() {
size = 0;
- Arrays.fill(buffer, CharUtils.NUL);
+ ArrayFill.clear(buffer);
return this;
}
@@ -1810,7 +1810,7 @@ public StrBuilder deleteFirst(final StrMatcher matcher) {
private void deleteImpl(final int startIndex, final int endIndex, final
int len) {
System.arraycopy(buffer, endIndex, buffer, startIndex, size -
endIndex);
size -= len;
- Arrays.fill(buffer, size, size + len, CharUtils.NUL);
+ ArrayFill.clear(buffer, size, size + len);
}
/**
@@ -1920,6 +1920,15 @@ public boolean equalsIgnoreCase(final StrBuilder other) {
return true;
}
+ /**
+ * Gets the internal buffer for testing.
+ *
+ * @return the internal buffer.
+ */
+ char[] getBuffer() {
+ return buffer;
+ }
+
/**
* Copies the character array into the specified array.
*
@@ -2682,14 +2691,14 @@ public StrBuilder replaceFirst(final StrMatcher
matcher, final String replaceStr
}
/**
- * Internal method to delete a range without validation.
+ * Internal method to replace a range without validation.
*
- * @param startIndex the start index, must be valid
- * @param endIndex the end index (exclusive), must be valid
- * @param removeLen the length to remove (endIndex - startIndex), must be
valid
- * @param insertStr the string to replace with, null means delete range
- * @param insertLen the length of the insert string, must be valid
- * @throws IndexOutOfBoundsException if any index is invalid
+ * @param startIndex the start index (inclusive), must be valid.
+ * @param endIndex the end index (exclusive), must be valid.
+ * @param removeLen the length to remove (endIndex - startIndex), must be
valid.
+ * @param insertStr the string to replace with, null means delete range.
+ * @param insertLen the length of the insert string, must be valid.
+ * @throws IndexOutOfBoundsException if any index is invalid.
*/
private void replaceImpl(final int startIndex, final int endIndex, final
int removeLen, final String insertStr, final int insertLen) {
final int newSize = size - removeLen + insertLen;
@@ -2815,12 +2824,12 @@ public StrBuilder setLength(final int length) {
throw new StringIndexOutOfBoundsException(length);
}
if (length < size) {
- size = length;
+ ArrayFill.clear(buffer, length, size);
} else if (length > size) {
ensureCapacity(length);
- Arrays.fill(buffer, size, length, CharUtils.NUL);
- size = length;
+ ArrayFill.clear(buffer, size, length);
}
+ size = length;
return this;
}
diff --git a/src/test/java/org/apache/commons/lang3/ArrayFillTest.java
b/src/test/java/org/apache/commons/lang3/ArrayFillTest.java
index 26e738d80..9888228a6 100644
--- a/src/test/java/org/apache/commons/lang3/ArrayFillTest.java
+++ b/src/test/java/org/apache/commons/lang3/ArrayFillTest.java
@@ -66,6 +66,24 @@ void testClearCharArrayNull() {
assertSame(array, actual);
}
+ @Test
+ void testClearCharArrayRange() {
+ final char[] array = {'A', 'B', 'C', 'D', 'E'};
+ final char[] actual = ArrayFill.clear(array, 1, 4);
+ assertSame(array, actual);
+ assertEquals('A', actual[0]);
+ assertEquals('\0', actual[1]);
+ assertEquals('\0', actual[2]);
+ assertEquals('\0', actual[3]);
+ assertEquals('E', actual[4]);
+ }
+
+ @Test
+ void testClearCharArrayRangeNull() {
+ final char[] actual = ArrayFill.clear(null, 0, 0);
+ assertNull(actual);
+ }
+
@Test
void testFillBooleanArray() {
final boolean[] array = new boolean[3];
@@ -123,6 +141,33 @@ void testFillCharArrayNull() {
assertSame(array, actual);
}
+ @Test
+ void testFillCharArrayRange() {
+ final char[] array = {'A', 'B', 'C', 'D', 'E'};
+ final char val = 'Z';
+ final char[] actual = ArrayFill.fill(array, 1, 4, val);
+ assertSame(array, actual);
+ assertEquals('A', actual[0]);
+ assertEquals('Z', actual[1]);
+ assertEquals('Z', actual[2]);
+ assertEquals('Z', actual[3]);
+ assertEquals('E', actual[4]);
+ }
+
+ @Test
+ void testFillCharArrayRangeEmpty() {
+ final char[] array = {'A', 'B', 'C'};
+ final char[] actual = ArrayFill.fill(array, 1, 1, 'Z');
+ assertSame(array, actual);
+ assertArrayEquals(new char[] {'A', 'B', 'C'}, actual);
+ }
+
+ @Test
+ void testFillCharArrayRangeNull() {
+ final char[] actual = ArrayFill.fill(null, 0, 0, 'Z');
+ assertNull(actual);
+ }
+
@Test
void testFillDoubleArray() {
final double[] array = new double[3];
diff --git
a/src/test/java/org/apache/commons/lang3/text/StrBuilderClearTest.java
b/src/test/java/org/apache/commons/lang3/text/StrBuilderClearTest.java
index 9765362b0..e499a1d20 100644
--- a/src/test/java/org/apache/commons/lang3/text/StrBuilderClearTest.java
+++ b/src/test/java/org/apache/commons/lang3/text/StrBuilderClearTest.java
@@ -17,7 +17,9 @@
package org.apache.commons.lang3.text;
+import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
import java.io.ByteArrayInputStream;
import java.io.IOException;
@@ -25,6 +27,7 @@
import java.io.Reader;
import java.nio.charset.StandardCharsets;
+import org.apache.commons.lang3.CharUtils;
import org.apache.commons.lang3.SerializationUtils;
import org.junit.jupiter.api.Test;
@@ -159,4 +162,24 @@ public void testStaleCharsNotLeakedAfterTruncate() throws
Exception {
// sb now logically contains "top_se"
assertFalse(containsUtf16Be(SerializationUtils.serialize(sb),
"secret_key_material"));
}
+
+ @Test
+ void testSetLengthShrinkLeavesResidual() throws Exception {
+ final String string = "CONFIDENTIAL_TOKEN_VALUE";
+ final int len = string.length();
+ final StrBuilder sb = new StrBuilder(string);
+ assertEquals(len, sb.length());
+ // setLength(5) shrinks: size = 5, but [5..24) is NOT cleared.
+ sb.setLength(5);
+ assertEquals(5, sb.length());
+ assertEquals("CONFI", sb.toString());
+ final char[] buf = sb.getBuffer();
+ assertTrue(buf.length >= len);
+ // Probe offset 10: original was 'L' (CONFIDENTIA*L*_TOKEN_VALUE).
+ assertEquals(CharUtils.NUL, buf[10]);
+ final StringBuilder dump = new StringBuilder();
+ for (int i = 5; i < len; i++) {
+ assertEquals(CharUtils.NUL, buf[i]);
+ }
+ }
}
