RFR: 8365626: (fs) Improve handling of broken links in Files.isSameFile() (win) [v8]

[Brian Burkhalter]

On Thu, 18 Sep 2025 16:31:17 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> src/java.base/windows/classes/sun/nio/fs/WindowsFileSystemProvider.java line 471:
>> 
>>> 469:                 try {
>>> 470:                     h = path.openForReadAttributeAccess(false);
>>> 471:                 } catch (WindowsException x) {
>> 
>> I think you'll need to init h to INVALID_HANDLE_VALUE here or when WindowsException is thrown, otherwise there is a risk that it will be closed twice, assuming I'm reading it correctly.
>
> I am probably missing something, but `h` is set to `INVALID_HANDLE_VALUE` before the while-loop is entered and reset to that value at line 486. It is set to a valid value at line 470 unless `openForReadAttributeAccess` throws an exception in which case it will be closed in the finally block. So it can only have a valid value between lines 478 and 484, inclusive. If there is a break or an exception in that line range, then `h` should be closed in the finally block. If there is an exception in the line range 490-491, then `h` will be `INVALID_HANDLE_VALUE` and would not be closed in the finally block.

Wait, I see. If `FileSystemLoopException` is thrown, then `h` could still be valid. Will change.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27079#discussion_r2360211514