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https://issues.apache.org/jira/browse/CODEC-340?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18088480#comment-18088480
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Ruiqi Dong commented on CODEC-340:
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If this issue is confirmed, I would like to submit a PR to fix it
> Base58.Builder#setEncodeTable(...) is ignored by Base58
> -------------------------------------------------------
>
> Key: CODEC-340
> URL: https://issues.apache.org/jira/browse/CODEC-340
> Project: Commons Codec
> Issue Type: Bug
> Reporter: Ruiqi Dong
> Priority: Major
>
> *Summary*
> Base58.Builder exposes setEncodeTable(...), which suggests a caller can
> configure a custom Base58 alphabet. However, Base58 encoding and decoding
> still use the hard-coded default alphabet internally. As a result, the
> builder accepts custom configuration that is silently ignored.
>
> *Affected code*
> File: src/main/java/org/apache/commons/codec/binary/Base58.java
> The builder accepts custom tables:
> {code:java}
> public Base58.Builder setEncodeTable(final byte... encodeTable) {
> super.setDecodeTableRaw(DECODE_TABLE);
> return super.setEncodeTable(encodeTable);
> } {code}
> But the codec still uses the built-in constants directly:
> {code:java}
> final int digit = b < DECODE_TABLE.length ? DECODE_TABLE[b] : -1; {code}
> {code:java}
> base58.append((char) ENCODE_TABLE[divRem[1].intValue()]); {code}
> {code:java}
> base58.append('1'); {code}
> So the configured alphabet is not used on either encode or decode.
>
> *Reproducer*
> Add the following test to
> src/test/java/org/apache/commons/codec/binary/Base58Test.java:
> {code:java}
> @Test
> void testBuilderCustomEncodeTableAffectsEncodeAndDecode() {
> final byte[] encodeTable =
> "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz".getBytes(StandardCharsets.US_ASCII);
> final byte tmp = encodeTable[0];
> encodeTable[0] = encodeTable[1];
> encodeTable[1] = tmp;
> final Base58 base58 = Base58.builder().setEncodeTable(encodeTable).get();
> assertEquals("1", new String(base58.encode(new byte[] {1}),
> StandardCharsets.US_ASCII),
> "A custom Base58 alphabet should affect encoding");
> assertArrayEquals(new byte[] {1},
> base58.decode("1".getBytes(StandardCharsets.US_ASCII)),
> "A custom Base58 alphabet should affect decoding consistently");
> } {code}
> Run:
> {code:java}
> mvn -q
> -Dtest=org.apache.commons.codec.binary.Base58Test#testBuilderCustomEncodeTableAffectsEncodeAndDecode
> test {code}
> Observed behavior:
> {code:java}
> expected: <1> but was: <2> {code}
> That is the output for the built-in alphabet, not the configured one.
>
> Expected behavior:
> If setEncodeTable(...) is part of the public builder API, the resulting
> Base58 instance should actually use that alphabet consistently for both
> encoding and decoding. Otherwise, the builder should reject the unsupported
> configuration instead of accepting it silently.
>
> This is a configuration/state bug in a public API. The builder records a
> custom alphabet, but the operational code paths ignore it and continue using
> the default constants. That makes the exposed configuration misleading and
> non-functional.
>
>
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