Re: [lmi] Cygwin build failure

[Greg Chicares]

On 2019-04-30 16:53, Vadim Zeitlin wrote:
> On Tue, 30 Apr 2019 15:43:47 +0000 Greg Chicares <address@hidden> wrote:
> 
> GC> I suspect that the anomaly stems from one of three causes: either
> GC>  - the '7-Zip' command doesn't do what 'bsdtar' does, and you're
> GC>    using the '7-Zip' command; or
> 
>  7z does do the same thing as bsdtar does, I've checked this. But in any
> case, I saw the problem even running bsdtar manually and the absence of any
> 7z output in the log shows that the script used bsdtar as well.

Then we should remove the '7-Zip' stuff from 'install_mingw.make',
knowing that we can always revert the removal if that ever becomes
necessary. That workaround is commented:

  # Fall back on a native binary if libarchive issue 629 occurs.

which is documented here:

  https://github.com/libarchive/libarchive/issues/629
| This problem appears to be related to compressing & decompressing
| large files with bsdtar shipped with libarchive v3.1.2.

and shouldn't arise again with a fresh cygwin installation unless
they have a really old version (mine is libarchive 3.3.3).

> GC> I'm often surprised by the result of copying directories with 'cp':
> GC> sometimes the contents are copied, and sometimes the directory (with
> GC> its contents) is copied instead. I've never found a good explanation.
> 
>  If the target directory exists, the source directory is copied into it. If
> it doesn't exist, then source directory is "renamed into" it.

I really wish there were some simple way of writing a 'cp' command
that would select between those behaviors without regard to the
prior existence of the target directory. But there isn't.

I found this, which is fascinating:

https://stackoverflow.com/questions/18158248/should-i-put-trailing-slash-after-source-and-destination-when-copy-folders/24925767#24925767

but others' opinions vary.

> GC> Do you know a way to write those commands that would avoid any
> GC> ambiguity?
> 
>  I don't know of any other way than ensuring that the target directory
> [does not] exist[s] before running the command.

In one of the commits I just pushed, I moved some mkdir commands
so that they immediately precede the 'cp' command, making it
easier to see the relationship.

>  Anyhow, the important question is how do we fix this?
I had assumed that the maintainers of *-w64-mingw32 used a
mingw32/ subdirectory for all their packages. Realizing
now that their x86_64-w64-mingw32 archives use mingw64/ ,
I think we should keep open the option of using that
potentially to support both in the same cygwin installation.
I've pushed that set of changes now.