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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: GNAT vs UTF-8 source file names
Date: Tue, 04 Jul 2017 14:57:03 +0100
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Date: 2017-07-04T14:57:03+01:00
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Simon Wright <simon@pushface.org> writes:

> PR ada/81114 refers[1].
>
> It turns out that this failure occurs on Windows and macOS. The problem
> is that GNAT smashes the file name to lower case if it knows that the
> file system is case-insensitive (using an ASCII to-lower, so of course
> 'smash' is the right word if there are UTF-8 characters in there).

> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81114

It's worse than that, on macOS anyway[2].

$ GNAT_FILE_NAME_CASE_SENSITIVE=1 gnatmake -c p*.ads
gcc -c páck3.ads
páck3.ads:1:10: warning: file name does not match unit name, should be "páck3.ads"

The reason for this apparently-bizarre message is[3] that macOS takes 
the composed form (lowercase a acute) and converts it under the hood 
to what HFS+ insists on, the fully decomposed form (lowercase a, combining 
acute); thus the names are actually different even though they _look_ 
the same.

I have to say that, great as it would be to have this fixed, the changes 
required would be extensive, and I can’t see that anyone would think it 
worth the trouble.

The recommendation would be "don’t use international characters in the 
names of library units".

[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81114#c1
[3] https://stackoverflow.com/a/6153713/40851