On Tue, 22 Mar 2022 06:54:35 GMT, Xin Liu <x...@openjdk.org> wrote:
>> src/java.base/share/classes/java/lang/AbstractStringBuilder.java line 1008:
>>
>>> 1006: this.count = newCount;
>>> 1007: putStringAt(start, str);
>>> 1008: if (end - start > 0) {
>>
>> regardless of value of `end - start` you could also skip setting
>> `maybeLatin1 = true` if:
>> - `str.coder() == UTF16`
>> - `this.coder == LATIN1`
>
> hi, @cl4es,
> you are correct for this and the comment at setCharAt(), but I don't think
> it's necessary to check all cases. this attribute is just like a hint. if
> this.coder == LATIN1, that it doesn't matter if maybeLatin1 is true.
>
> if our attitude is checking all cases, it will become too complex and
> error-prone. deleteCharAt() and setLength() also need to check. if so, it
> will pollute code more. I incline to set this attribute conservatively in all
> deleting methods.
Right, we don't need to check every case and I agree with favoring simplicity
at the expense of some false positives. Perhaps the `if (end - start > 0) {`
test here isn't pulling its weight either and we should just unconditionally
set `maybeLatin1 = true` even if we're not actually replacing anything (which
is very much a corner-case).
-------------
PR: https://git.openjdk.java.net/jdk/pull/7671
