[LANG-1645] NumberUtils.createNumber/createBigInteger fails on hexidecimal integers prefixed with +

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.12.0
• Fix Version/s: 3.13.0
• Component/s: lang.math.*
• Assignee: Alex Herbert
• Reporter: Alex Herbert
• Created: 04/Mar/21 15:00
• Updated: 05/Mar/21 11:48
• Resolved: 05/Mar/21 11:48

Description

The Java Language Specification allows an optional sign prefix for a number as + or -.

A + sign before a hex integer is not recognised by createNumber and createBigInteger but is recognised by isCreatable, createInteger and createLong. The two later functions delegate to Java's decode() function that handles an optional leading +.

The following demonstrates the tests that fail but would pass if the leading '+' is removed.

    @Test
    void testCreatePositiveHexInteger() {
        // Hex is only supported for integers so no test for hex floating point formats
        assertTrue(NumberUtils.isCreatable("+0xF"));
        assertTrue(NumberUtils.isCreatable("+0xFFFFFFFF"));
        assertTrue(NumberUtils.isCreatable("+0xFFFFFFFFFFFFFFFFF"));

        assertEquals(Integer.decode("+0xF"), NumberUtils.createInteger("+0xF"));
        assertEquals(Long.decode("+0xFFFFFFFF"), NumberUtils.createLong("+0xFFFFFFFF"));

        assertEquals(new BigInteger("+FFFFFFFFFFFFFFFF", 16),
                     NumberUtils.createBigInteger("0xFFFFFFFFFFFFFFFF"));
        try {
            assertEquals(new BigInteger("+FFFFFFFFFFFFFFFF", 16),
                         NumberUtils.createBigInteger("+0xFFFFFFFFFFFFFFFF"));
            Assertions.fail("This should be possible but it is not");
        } catch (NumberFormatException ex) {
            // This should not happen
        }

        assertEquals(Integer.decode("+0xF"),
                     NumberUtils.createNumber("0xF"));
        try {
            assertEquals(Integer.decode("+0xF"),
                         NumberUtils.createNumber("+0xF"));
            Assertions.fail("This should be possible but it is not");
        } catch (NumberFormatException ex) {
            // This should not happen
        }

        assertEquals(Long.decode("+0xFFFFFFFF"),
                     NumberUtils.createNumber("0xFFFFFFFF"));
        try {
            assertEquals(Long.decode("+0xFFFFFFFF"),
                         NumberUtils.createNumber("+0xFFFFFFFF"));
            Assertions.fail("This should be possible but it is not");
        } catch (NumberFormatException ex) {
            // This should not happen
        }

        assertEquals(new BigInteger("+FFFFFFFFFFFFFFFF", 16),
                     NumberUtils.createNumber("0xFFFFFFFFFFFFFFFF"));
        try {
            assertEquals(new BigInteger("+FFFFFFFFFFFFFFFF", 16),
                         NumberUtils.createNumber("+0xFFFFFFFFFFFFFFFF"));
            Assertions.fail("This should be possible but it is not");
        } catch (NumberFormatException ex) {
            // This should not happen
        }
    }

A simple fix is to check for a leading '+' character and advance all processing past this character.