SftpFileSystemProvider.newFileChannel() uses wrong default mode

[tomaswolf]

Version

master

Bug description

According to the contract of FileSystemProvider.newFileChannel() per its javadoc, the channel is opened read-only if no OpenOptions are passed.

SftpFileSystemProvider opens the channel in read-write mode in this case.

Actual behavior

Channel is opened read-write, which fails if the remote file is read-only.

Expected behavior

Channel is opened read-only if SftpFileSystemProvider.newFileChannel(path) is called without OpenOptions.

Relevant log output

No response

Other information

No response

[hannibal218bc]

Hi,

thank you for taking care of this issue. Sorry for nickpicking, but the description "the channel is opened read-only if no OpenOptions are passed" is not correct.

The contract actually is "If neither option (WRITE or APPEND, ed.) is contained in the array then the file is opened for reading".

[tomaswolf]

Yes, but I would not read this too literally. All the other options imply write access, don't they?

[hannibal218bc]

Yes, but I would not read this too literally. All the other options imply write access, don't they?

I thought specs are meant to be taken literally ;-) but yes, I agree that e.g. SYNC probably isn't useful on a read-only file. However, I think with e.g. CREATE it is not that clear.

[tomaswolf]

No sure there's a use case for CREATE, READ. For now I think your change #372 is fine (setting READ if no options). We can change it later to "set READ if neither WRITE nor APPEND present", if needed, but then that should probably be done in other places as well.

Do you want to fix the failing tests? I prefer to have master working at any commit, so if you could amend your commit, that'd be great; then I could merge it.

[hannibal218bc]

Sure, I've just force-pushed faf88ec , could you please approve the action workflow run? 👍