RFR: 8324635: (zipfs) Regression in Files.setPosixFilePermissions called on existing MSDOS entries

[Lance Andersen]

On Wed, 24 Jan 2024 14:34:03 GMT, Eirik Bjørsnøs <eirbjo at openjdk.org> wrote:

> Please review this PR to fix to a regression in ZipFileSystem, introduced by JDK-8322565 in PR #17170.
> 
> When `Files.setPosixFilePermissions` is called on an existing MSDOS entry, then `Entry.posixPerms` field will be -1 (all 1s in binary). The logic introduced by JDK-8322565 did not account for this and incorrectly sets the leading seven bits to all ones instead of all zeros.
> 
> The fix is to introduce a branch for `Entry.posixPerms` being -1 and deal with that case separately.
> 
> The PR adds a test case to `TestPosix` which reproduces the regression. While visiting this test, I also fixed an incorrect spelling of `setPosixFilePermissions` (also introduced by #17170).

Looks OK overall.  One minor suggestion

test/jdk/jdk/nio/zipfs/TestPosix.java line 757:

> 755:         try (FileSystem fs = FileSystems.newFileSystem(ZIP_FILE, ENV_POSIX)) {
> 756:             Path path = fs.getPath("hello.txt");
> 757:             Files.setPosixFilePermissions(path, EnumSet.of(OWNER_READ));

It might be helpful to show the before/after output of the CEN fields here just for extra clarity

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Marked as reviewed by lancea (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17556#pullrequestreview-1860241911
PR Review Comment: https://git.openjdk.org/jdk/pull/17556#discussion_r1476630176