System.Teminal.hsc fails to compile on a Solaris-family OS

[Bodigrim]

This has been reported at https://www.reddit.com/r/haskell/comments/1nrt23b/comment/ngka3xp/ as a failure to a build Stack itself:

<command-line>: note: this is the location of the previous definition
In file included from /root/stack-3.7.1/dist-newstyle/build/x86_64-solaris/ghc-9.8.2/stack-3.7.1/build/System/Terminal_hsc_make.c:1:
Terminal.hsc: In function 'main':
Terminal.hsc:28:15: error: invalid application of 'sizeof' to incomplete type 'struct winsize'
/opt/local/lib/ghc-9.8.2/lib/template-hsc.h:96:39: note: in definition of macro 'hsc_size'
   96 |     hsc_printf("(%ld)", (long) sizeof(t));
      |                                       ^
/opt/local/lib/ghc-9.8.2/lib/template-hsc.h:102:9: error: field 'b' has incomplete type
  102 |       x b;                                                            \
      |         ^
Terminal.hsc:29:5: note: in expansion of macro 'hsc_alignment'
In file included from /opt/local/lib/ghc-9.8.2/lib/template-hsc.h:11:
/opt/local/lib/ghc-9.8.2/lib/template-hsc.h:82:24: error: invalid use of undefined type 'struct winsize'
   82 |                 (long) offsetof (t, f));
      |

This seemingly stems from

stack/src/unix/System/Terminal.hsc

Lines 27 to 32 in b2457a8

	instance Storable WindowWidth where
	sizeOf _ = (#size struct winsize)
	alignment _ = (#alignment struct winsize)
	peek p = WindowWidth <$> (#peek struct winsize, ws_col) p
	poke p (WindowWidth w) = do
	(#poke struct winsize, ws_col) p w

I have no idea what's going on. Looking at a similar functionality in https://github.com/biegunka/terminal-size/blob/master/src/System/Console/Terminal/Posix.hsc, I notice a suspicious line

#let alignment t = "%lu", (unsigned long)offsetof(struct {char x__; t (y__); }, y__)

which might or might not have to do something with the latter error.

BTW is there a reason stack does not use terminal-size to get the terminal width and rolls out its own implementation?

[mpilgrem]

By way of introduction, I've not found anything to suggest that Solaris/x86-64 is a platform supported in any way by GHC: https://gitlab.haskell.org/ghc/ghc/-/wikis/platforms. The Stack project does not aim to support platforms that the GHC project itself does not support.

That part of Stack's code dates from 2017:

• 0cf7ba9

Stack is using GHC's hsc2hs preprocessor.

Stack moved to using the terminal-size package in 2019:

• 9b34190

but dropped it again, a few months later:

• "'stty' is not recognised" #4901
• Inhibit errors from terminal-size #4968
• 3a98628

at that time, the terminal-size package was viewed as buggy and effectively unmaintained.

[mpilgrem]

@Bodigrim, ChatGPT may be hallucinating, but it tells me that on Solaris it is the header termios.h, not sys/ioctl.h (as in the case of Linux), that defines struct winsize.

[Bodigrim]

https://docs.oracle.com/cd/E86824_01/html/E54777/termio-7i.html suggets so, yes.

[mpilgrem]

@Bodigrim, I've added a suggestion to the Reddit thread, accordingly.