RFR: 8350880: (zipfs) Add support for read-only zip file systems [v3]

[David Beaumont]

On Mon, 12 May 2025 15:57:35 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> David Beaumont has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fix comment based on current behaviour.
>
> src/jdk.zipfs/share/classes/module-info.java line 160:
> 
>> 158:  *       will always be opened <em>read-write</em> (see {@code "accessMode"}
>> 159:  *       below), regardless of whether the underlying ZIP already existed or
>> 160:  *       not.
> 
> In the default provider, "read-only && create" ignores the create option so the open fails if the file does not exist.
> 
> For the zipfs provider then doing the same, or having this combination be an error, is okay. I think it might be a bit too surprising to have "read-only && create" create a read-write file system.

Is this comment just agreeing with the proposed behaviour stated here?

At the moment the code prohibits "read-only && create". It's an illegal argument exception (see tests).

The only allowed access mode options with "create" are "readWrite" or <no-option>, and in both cases you get back a ZipFileSystem for which "isReadOnly()" is false. We'd already agreed that any explicit access mode needs to always be honoured.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25178#discussion_r2085381219