"std.file.copy" now completely ignores the "PreserveAttributes.no" argument on Windows

[dlangBugzillaToGithub]

bugzilla (@WalterBright) reported this on 2018-09-04T21:45:14Z

Transfered from https://issues.dlang.org/show_bug.cgi?id=19221

Description

On 04/09/2018 10:27 PM, Ecstatic Coder wrote:
> On Tuesday, 4 September 2018 at 09:56:13 UTC, rikki cattermole wrote:
>> On 04/09/2018 9:40 PM, Ecstatic Coder wrote:
>>> But it seems that the latest version of "std.file.copy" now completely ignores the "PreserveAttributes.no" argument on Windows, which made recent Windows builds of Resync fail on read-only files.
>>
>> What???
>>
>> There is nothing in the changelog between 2.080.0 and 2.082.0 for changes to std.file.
>>
>> Version from July 2017[0]. Version from 2.082.0[1]. They look the same to me.
>>
>> [0] https://github.com/dlang/phobos/blob/d8959320e0c47a1861e32bbbf6a3ba30a019798e/std/file.d#L3430
>> [1] https://github.com/dlang/phobos/blob/v2.082.0/std/file.d#L4216
>
> Mayb I'm wrong, but what I can say is that I've recently updated DMD and compiled a windows build of Resync, and that I *HAD* to make Windows-specific code that removes the "read-only" attributes only on Windows.
>
> attributes = source_file_path.getAttributes();
> source_file_path.getTimes( access_time, modification_time );
>
> version ( Windows )
> {
>      if ( target_file_path.exists() )
>      {
>          target_file_path.setAttributes( attributes & ~1 );
>      }
>
>      source_file_path.copy( target_file_path, PreserveAttributes.no );
>      target_file_path.setAttributes( attributes & ~1 );
>      target_file_path.setTimes( access_time, modification_time );
>      target_file_path.setAttributes( attributes );
> }
> else
> {
>      if ( target_file_path.exists() )
>      {
>          target_file_path.setAttributes( 511 );
>      }
>
>      source_file_path.copy( target_file_path, PreserveAttributes.no );
>      target_file_path.setAttributes( attributes );
>      target_file_path.setTimes( access_time, modification_time );
> }
>
> Honestly I don't see why I have to make this ugly fix on Windows, while the Linux version has always worked fine on read-only files.

Hang on a second.

assert(preserve == Yes.preserveAttributes);

Something is smelling an awful lot here.

Up to Windows 7 CopyFileW which is used for Windows didn't copy the attributes over[0] but it does now.

This is a bug on our end, which should include a fallback to copying manually the file contents over.

[0] https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-copyfilew

[dlangBugzillaToGithub]

bugzilla (@WalterBright) commented on 2018-09-04T21:46:03Z

(above was posted by Rick Cattermole)