Salt length limit

[laurikimmel]

Metadata

Issue type: bug/documentation improvement

Description

Only first x characters of a salt have effect on encoding result. It's undocumented and not clear whether it's a feature or a bug.

Steps to Reproduce

Following test is failing

    @Test
    public void testSaltLenght() {
        int limit = 128;
        int minHashLength = 7;
        long input = 1;
        for (int i = 0; i < limit; i++) {
            String prefix = org.apache.commons.lang3.RandomStringUtils.randomAscii(i);
            Hashids h1 = new Hashids.Builder().minLength(minHashLength).salt(prefix + "A").build();
            Hashids h2 = new Hashids.Builder().minLength(minHashLength).salt(prefix + "B").build();
            String s1 = h1.encode(input);
            String s2 = h2.encode(input);
            assertThat("i: " + i + "; prfix: '" + prefix + "'", s1, is(not(equalTo(s2))));
        }
    }

Expected Behavior

Test case above should not fail in case salt length is unlimited.

Actual Behavior

Test case fails usually around i = 45. Lowest I have seen is i = 32 which is likely related to randomly generated prefix value.

Input value looks to have effect too. When input = Hashids.MAX_INTEROP_NUMBER_SIZE test case fails usually when 41 < i < 44.

Example

Environment and Versions

IceCore Hashids: 0.4.0
OS: MacOS 11.0.1
JDK: OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.8+10)
Running in IDE and Gradle