| 15 Jul 2025 |
 sterni (he/him) | I have a draft pr with it | 09:36:18 |
 nf | has anyone seen this error before with the GHC JS backend?
Aborted('HEAP8' was not exported. add it to EXPORTED_RUNTIME_METHODS (see the Emscripten FAQ))
(nix run github:ncfavier/glam/ghcjs-backend#glam-js to reproduce; say yes at the prompts to avoid building GHC)
| 11:10:59 |
 maralorn | ncfavier: Yes! That is a known issue. | 11:24:12 |
| maralorn | I have upstreamed a fix in ghc, which is not yet released and funnily I don’t think the fix works anyway. 😄 However there is a known to be working workaround:
Put this in the executable part of your .cabal file.
-- Workaround for a runtime error ("HEAP8 not found"). Only necessary until
-- https://gitlab.haskell.org/ghc/ghc/-/merge_requests/14362 is resolved.
ld-options: -sEXPORTED_RUNTIME_METHODS=HEAP8,HEAPU8
| 11:26:25 |
| maralorn | One of the causes here is that the emscripten version used in ghc CI is older than in nixpkgs. | 11:28:35 |
| nf | amazing, thank you so much! | 11:33:49 |
 alexfmpe | Wonder if we should add the ghc issue as an eval warning heh | 13:03:47 |
| nf | maybe we could just add that to the default cabal flags if stdenv.hostPlatform.isGhcjs or something | 13:55:13 |
| alexfmpe | if it's morally a "ghc backport" I agree | 14:44:10 |
| alexfmpe | otherwise it can get weird if upstream is injecting ld-options and what not for you | 14:44:32 |
| alexfmpe | silently | 14:44:37 |
| maralorn | The major problem with ld-options is that they override preconfigured ld-options. | 15:23:30 |
| maralorn | Which is no problem for the js backend because it currently has none. | 15:23:46 |
| maralorn | But in general they are mainly meant for ghc devs for debugging purposes and bgamari dislikes the fact that they are exposed via cabal options. | 15:24:41 |
| nf | * has anyone seen this error before with the GHC JS backend?
Aborted('HEAP8' was not exported. add it to EXPORTED_RUNTIME_METHODS (see the Emscripten FAQ))
| 16:06:43 |
| 16 Jul 2025 |
| nf | Is this the blessed way to write an overlay that adds a package foo to all Haskell package sets, without undoing previous overlays? If so, should we add it to the manual?
final: prev: {
haskell = prev.haskell // {
packageOverrides = final.lib.composeExtensions prev.haskell.packageOverrides
(hfinal: hprev: {
foo = ...;
});
};
}
| 15:13:51 |
| nf | * Is this the blessed way to write an overlay that adds a package foo to all Haskell package sets, without undoing previous overlays? If so, should we add it to the manual? If not, what is?
final: prev: {
haskell = prev.haskell // {
packageOverrides = final.lib.composeExtensions prev.haskell.packageOverrides
(hfinal: hprev: {
foo = ...;
});
};
}
| 15:15:17 |
| maralorn | lgtm | 15:16:00 |
| sterni (he/him) | https://www.haskell.org/ghc/blog/20250702-ghc-release-schedules.html | 22:38:21 |
| maralorn | Yeah. I am wondering what that’s gonna mean for stackage LTS. | 23:08:20 |
| 17 Jul 2025 |
|  kubitess joined the room. | 11:57:34 |
| 18 Jul 2025 |
|  @dmjio:matrix.org set a profile picture. | 00:21:22 |
| @dmjio:matrix.org left the room. | 14:28:22 |
| 19 Jul 2025 |
 Patrick Steele | Indeed, cabal run --enable-profiling myprog -- +RTS -p worked | 21:07:44 |
| Patrick Steele | without modification to the cabal file, i.e. no -prof | 21:08:05 |
| 20 Jul 2025 |
 Profpatsch | gonna switch to 9.14 and never update again | 13:11:26 |
| maralorn | In reply to @profpatsch:augsburg.one
gonna switch to 9.14 and never update again I feel like I am missing context. 🤣 | 22:09:55 |
| 21 Jul 2025 |
| Profpatsch | LTS | 00:09:46 |
 magic_rb | im benchmarking a thing i wrote and im making a nix package out of a cabal file using cabal2nix, however if i change the source cabal file and remove -fllvm, -O2, or -fexpose-all-unfoldings the performance measurements dont seem to change even though im positive they should. Is nixpkgs overwriting my flags somehow? | 09:41:41 |
| magic_rb | im now trying the same bench but build outside of nixpkgs | 09:45:07 |
