RFR: 8355342: File.getCanonicalPath on Java 24 resolves paths on network drives to UNC format [v6]

[Brian Burkhalter]

On Fri, 17 Oct 2025 22:50:59 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> `File.getCanonicalPath` invokes `GetFinalPathNameByHandle` on the result of `canonicalize0` which causes the drive letter of a mapped drive to be converted to a UNC prefix. If such a substitution is detected, this request proposes to revert the conversion of drive letter to UNC prefix before returning the canonical path.
>
> Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8355342: Do not check for backslash as third character of input pathname string

src/java.base/windows/classes/java/io/WinNTFileSystem.java line 504:

> 502:                 finalPath = fp;
> 503:             }
> 504:         } catch (IOException ignored) {

I don't know that there should be a `try-catch` here as it looks like `getFinalPath` throws (an `Error`) if any only if memory runs out, in which case we're done anyway.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27324#discussion_r2441409842