RFR: 8256828: ostream::print_cr() truncates buffer in copy-through case [v3]

[David Holmes]

On Tue, 4 Jun 2024 04:36:30 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> David Holmes has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   revert constexpr usage
>
> src/hotspot/share/utilities/ostream.cpp line 142:
> 
>> 140:     warning("outputStream::do_vsnprintf output truncated -- buffer length is " SIZE_FORMAT
>> 141:             " bytes but " SIZE_FORMAT " bytes are needed.",
>> 142:             add_cr ? buflen + 1 : buflen, required_len + 1);
> 
> PrintWarnings defaults to true, right? Ah, I see, you limit to debug builds. Okay.

Yes same as before.

> test/hotspot/gtest/utilities/test_ostream.cpp line 147:
> 
>> 145:     va_list ap;
>> 146:     va_start(ap, format);
>> 147:     const char* res = tty->do_vsnprintf(buf, len, format, ap, add_cr, rlen);
> 
> This was confusing at first glance. Any reason you use tty instead of just defaultStream::do_vsnprintf? Or, outputStream::do_vsnprintf?

Ha! OMG I never even noticed `do_vnsprintf` is static - everything else is an instance method so I used `tty`. Okay I can simplify this and move the test class to outputStream

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PR Review Comment: https://git.openjdk.org/jdk/pull/19512#discussion_r1625453279
PR Review Comment: https://git.openjdk.org/jdk/pull/19512#discussion_r1625452545