RFR: 8266078: Reader.read(CharBuffer) advances Reader position for read-only Charbuffers [v2]

[Alan Bateman]

On Tue, 27 Apr 2021 20:25:32 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> Please consider this request to modify `Reader.read(CharBuffer)` to check whether the buffer is read-only before reading any characters from the character stream. This can happen now if the buffer is read-only. Character are first read thereby advancing the stream before an attempt is made to put them in the `CharBuffer` thus incorrectly advancing the stream position.
>
> Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8266078: Make read-only check global; add message in test

Marked as reviewed by alanb (Reviewer).

src/java.base/share/classes/java/io/Reader.java line 206:

> 204:             char[] cbuf = new char[len];
> 205:             // If a read-only check had not been done above, then
> 206:             // the stream would be incorrectly advanced here.

The RO check is good but I'm not sure that this comment is useful (it might confuse future maintainers), I would be tempted to leave that part out.

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PR: https://git.openjdk.java.net/jdk/pull/3725