Gloss crashes on mac

[turion]

Apparently on a mac, starting gloss/GLUT crashes:

$ cabal repl
Build profile: -w ghc-8.8.3 -O1
In order, the following will be built (use -v for more details):
 - essence-of-live-coding-tutorial-0.2.0.1 (exe:essence-of-live-coding-tutorial) (first run)
Preprocessing executable 'essence-of-live-coding-tutorial' for essence-of-live-coding-tutorial-0.2.0.1..
GHCi, version 8.8.3: https://www.haskell.org/ghc/  :? for help
Loaded GHCi configuration from /Users/ninagermanus/repos/essence-of-live-coding-tutorial/.ghci
[1 of 1] Compiling Main             ( Main.hs, interpreted )
Ok, one module loaded.
*Main LiveCoding LiveCoding.GHCi> :livelaunch
*Main LiveCoding LiveCoding.GHCi> 2020-08-14 14:44:29.130 ghc[27231:4244082] WARNING: NSWindow drag regions should only be invalidated on the Main Thread! This will throw an exception in the future. Called from (
	0   AppKit                              0x00007fff366e5607 -[NSWindow(NSWindow_Theme) _postWindowNeedsToResetDragMarginsUnlessPostingDisabled] + 378
	1   AppKit                              0x00007fff366e29f7 -[NSWindow _initContent:styleMask:backing:defer:contentView:] + 1479
	2   AppKit                              0x00007fff366e242a -[NSWindow initWithContentRect:styleMask:backing:defer:] + 45
	3   GLUT                                0x00007fff3b699219 -[GLUTWindow _initWithContentRect:styleMask:contentView:] + 84
	4   GLUT                                0x00007fff3b699413 -[GLUTWindow initWithContentRect:pixelFormat:windowID:gameMode:treatAsSingle:] + 353
	5   GLUT                                0x00007fff3b6ab2b8 __glutCreateWindow + 578
	6   GLUT                                0x00007fff3b6ab4ae glutCreateWindow + 239
	7   libHSGLUT-2.7.0.15-3FcmcLd3ijWBc9FSar8jLE-ghc8.8.3.dylib 0x000000010e54057a LcWxZ_info + 114
)
EventResize (600,786)
2020-08-14 14:44:29.251 ghc[27231:4244082] GLUT Fatal Error: internal error: NSInternalInconsistencyException, reason: nextEventMatchingMask should only be called from the Main Thread!

cabal: repl failed for exe:essence-of-live-coding-tutorial from
essence-of-live-coding-tutorial-0.2.0.1.

Found by @pixln

[turion]

@pixln

Could you try the following:

git clone https://github.com/turion/essence-of-live-coding
cd essence-of-live-coding
nix-shell
cd essence-of-live-coding-gloss-example
cabal repl
:livelaunch

This should result in the same error.

Now to hopefully fix it, leave the REPL again and do this:

git checkout dev_forkOS
cabal repl
:livelaunch

This should give a window with 2 balls, and if you click in it, they'll start dancing. Does that work?

Background: https://stackoverflow.com/questions/45197922/glut-fatal-error-when-using-haskell-graphics-gloss

[turion]

We tried additionally to replace further occurrences of forkIO by forkOS, to no avail.

[turion]

@pixln Can you try cabal repl -fglfw?

[pixln]

I tried it, unfortunately, it still leads to the same error message.

➜  essence-of-live-coding git:(dev_forkOS) ✗ nix-shell

[nix-shell:~/repos/essence-of-live-coding]$ cd essence-of-live-coding-gloss-example/

[nix-shell:~/repos/essence-of-live-coding/essence-of-live-coding-gloss-example]$ cabal repl -fglfw
Resolving dependencies...
Build profile: -w ghc-8.8.3 -O1
In order, the following will be built (use -v for more details):
 - essence-of-live-coding-gloss-example-0.2.1 (exe:essence-of-live-coding-gloss-example) (first run)
Preprocessing executable 'essence-of-live-coding-gloss-example' for essence-of-live-coding-gloss-example-0.2.1..
GHCi, version 8.8.3: https://www.haskell.org/ghc/  :? for help
cannot satisfy -package essence-of-live-coding-gloss-example
    (use -v for more information)
Loaded GHCi configuration from /Users/ninagermanus/repos/essence-of-live-coding/essence-of-live-coding-gloss-example/.ghci
[1 of 1] Compiling Main             ( app/Main.hs, interpreted )
Ok, one module loaded.
*Main LiveCoding.GHCi Control.Concurrent> :livelaunch
*Main LiveCoding.GHCi Control.Concurrent> 2020-08-21 16:05:33.017 ghc[33735:10551371] WARNING: NSWindow drag regions should only be invalidated on the Main Thread! This will throw an exception in the future. Called from (
	0   AppKit                              0x00007fff366e5607 -[NSWindow(NSWindow_Theme) _postWindowNeedsToResetDragMarginsUnlessPostingDisabled] + 378
	1   AppKit                              0x00007fff366e29f7 -[NSWindow _initContent:styleMask:backing:defer:contentView:] + 1479
	2   AppKit                              0x00007fff366e242a -[NSWindow initWithContentRect:styleMask:backing:defer:] + 45
	3   GLUT                                0x00007fff3b699219 -[GLUTWindow _initWithContentRect:styleMask:contentView:] + 84
	4   GLUT                                0x00007fff3b699413 -[GLUTWindow initWithContentRect:pixelFormat:windowID:gameMode:treatAsSingle:] + 353
	5   GLUT                                0x00007fff3b6ab2b8 __glutCreateWindow + 578
	6   GLUT                                0x00007fff3b6ab4ae glutCreateWindow + 239
	7   libHSGLUT-2.7.0.15-3FcmcLd3ijWBc9FSar8jLE-ghc8.8.3.dylib 0x0000000119c8357a LcWxZ_info + 114
)
EventResize (600,792)
2020-08-21 16:05:33.135 ghc[33735:10551371] GLUT Fatal Error: internal error: NSInternalInconsistencyException, reason: nextEventMatchingMask should only be called from the Main Thread!

cabal: repl failed for exe:essence-of-live-coding-gloss-example from
essence-of-live-coding-gloss-example-0.2.1.

[turion]

Hmmm, strange. It seems like the flag didn't have any effect, since you still have "GLUT Fatal Error". But with this flag, GLUT shouldn't even run. I probably got the way these flags work wrong. Can you execute cabal configure --constraint 'essence-of-live-coding-tutorial glfw', and then try cabal repl?

[turion]

I got the command wrong again I think. cabal configure --constraint 'gloss glfw', and then try cabal repl.

[turion]

Adding the constraint gloss +glfw -glut seemed to work for cabal run, but not for cabal repl.

@pixln Can you try cabal repl -- constraint="gloss +glfw -glut"?

[turion]

Also, the flags might have to be upper case, +GLFW -GLUT.

A further option to try is executing cabal install gloss --flags="GLFW -GLUT" first.

[turion]

@pixln I got help from @hvr, who suggests to do:

cabal repl --constraint "gloss source" --constraint "gloss +GLWF -GLUT"

Can you try that?

[thielema]

cabal repl --constraint "gloss source" --constraint "gloss +GLWF -GLUT"

Never knew this syntax. Looks like advanced Cabal usage.
So far I use a cabal sandbox, and I guess nix-style local builds plus a cabal.project file would work too.