Create read-only file fails on nightly

[danburkert]

cc @alexcrichton

There has recently been a regression introduced to std::fs. The following line results in Ok on stable and Err on nightly:

std::fs::OpenOptions::new().read(true).create(true).open("some-file")

This regression is affecting Linux, Windows, and OS X. You can see it in action in recent fs2 CI builds.

[alexcrichton]

This is a known change in behavior implemented in #30872 as proposed in RFC 1252. This case was specifically disallowed due to its inconsistent behavior across platforms. Adding write(true) should guarantee it works on all platforms and on all versions.

[alexcrichton]

nominating for discussion of the fallout, however

[pitdicker]

A link in the RFC is broken, but this is from the OpenBSD mailing list. It says it does not work on OpenBSD and Solaris

[danburkert]

Ok sounds good. I didn't realize it wasn't available everywhere. I'll
update my code accordingly.

On Saturday, February 6, 2016, pitdicker [email protected] wrote:

A link in the RFC is broken, but this is from the OpenBSD mailing list
http://marc.info/?l=openbsd-tech&m=96976914719648. It says it does not
work on OpenBSD and Solaris

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#31453 (comment).

[pitdicker]

But sorry for the breakage anyway

[alexcrichton]

The libs team discussed this during triage today and decided that the fallout here is acceptable under the API evolution RFC, so closing.

Thanks again for the report though!