Remove `MonadFail (ST s)` instance(s)

[phadej]

These instances are now implemented as

instance MonadFail (ST s) where
    fail s = errorWithoutStackTrace s

for both strict and lazy as ST, and these are very much against the spirit of MonadFail proposal.

[chessai]

Agree. +1 for removal

[treeowl]

Get them out! I thought I remembered having proposed such a thing a few years ago.

[thielema]

On Fri, 21 Jan 2022, Oleg Grenrus wrote: These instances are now implemented as instance MonadFail (ST s) where fail s = errorWithoutStackTrace s for both strict and lazy as ST, and these are very much against the spirit of MonadFail proposal.

Right. So please remove them!

[Bodigrim]

I hate to say it, but we need an impact assessment. Someone needs to prepare GHC 9.0 with the proposed patch and then build https://github.com/Bodigrim/clc-stackage against it.

[phadej]

I hate to say it, but we need an impact assessment. Someone needs to prepare GHC 9.0 with the proposed patch and then build https://github.com/Bodigrim/clc-stackage against it.

I won't be able to do it anytime soon, so any help is welcome.

[ulysses4ever]

@Bodigrim I tried that and clc-stackage fails for vanilla GHC 9.0.1 with

❯ cabal build
Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: clc-stackage-0.1.0.0 (user goal)
[__1] next goal: hfsevents (dependency of clc-stackage)
[__1] rejecting: hfsevents-0.1.6 (library is not buildable in the current
environment, but it is required by clc-stackage)
[__1] rejecting: hfsevents-0.1.5 (conflict: clc-stackage => hfsevents==0.1.6)
[__1] skipping: hfsevents-0.1.4, hfsevents-0.1.3, hfsevents-0.1.2,
hfsevents-0.1.1, hfsevents-0.1 (has the same characteristics that caused the
previous version to fail: excluded by constraint '==0.1.6' from
'clc-stackage')
[__1] fail (backjumping, conflict set: clc-stackage, hfsevents)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: clc-stackage, hfsevents

hfeevents not on the list in the cabal file. Any suggestions how to fix it?

[Bodigrim]

Just remove it from clc-stackage.cabal, it's OS X specific package.

[ulysses4ever]

I've been trying to build clc-stackage, and here's a quick recap. First, it goes slowly because I keep hitting "Missing dependencies on foreign libraries" like OpenGL stuff, and restarting the process every time is slow.

Interesting breakages so far (with links to particular break points):

• double-conversion
• fgl
• lzma

I'm currently stuck because even after removing the said packages, the solver insists on building them. They're probably dependencies of some other packages (e.g. fgl has ~115 reverse dependencies), so I'm not sure how to proceed at this point.

I'd guess, that a better process would be to (try to) build every package separately, but I'd need to get around to write some bash for that. Even better would be to employ Nix to avoid the missing native dependencies problem, I guess.

[phadej]

@ulysses4ever nice!

• In lzma we should use error. Using fail there is just wrong. (I'll fix that, being a co-maintainer).
• double-conversion is also using fail instead of error
• fgl is bad:

class MonadFail m => GraphM m gr where

is just a such big lie. See https://hackage.haskell.org/package/fgl-5.7.0.3/docs/src/Data.Graph.Inductive.Monad.html#GraphM
There authors are using fail for error. Yes, it behaves better in IO, but it's wrong in ST.

These breakages pin point poorly written code, which is my intention with this proposal.

[ulysses4ever]

I'm sorry but cabal-install giving me hard time today. I'm trying to build Bodigrim/clc-stackage after today's update where we removed several packages with native dependencies, for example: bindings-GLFW, OpenGLRaw. Yet, the build fails citing (among others) these very packages, and (most surprising) clc-stackage as its dependent:

cabal: Failed to build OpenGLRaw-3.3.4.1 (which is required by
exe:clc-stackage from clc-stackage-0.1.0.0). See the build log above for
details.
Failed to build bindings-GLFW-3.3.2.0 (which is required by exe:clc-stackage
from clc-stackage-0.1.0.0). See the build log above for details.

Maybe it's a wrong place to ask, but why is this happening? To be sure, I checked with grep that the said packages are not mentioned in the clc-stackage's cabal file. I tried cabal clean and removing dist-newstyle. Full output of cabal build is here.

---

Meanwhile, another breakage is in regex-tdfa (failable patterns).

[ulysses4ever]

Quick update on building Stackage (~2600 packages) under this change. It's done, and here's a list of 8 packages (including 4 mentioned above) that failed to build on their own because of the change; via a click on the package name you can get the build output. For posterity, the list is:

• cborg-0.2.6.0
• double-conversion-2.0.2.0
• fgl-5.7.0.3
• lzma-0.0.0.3
• regex-tdfa-1.3.1.1
• union-find-0.2
• xeno-0.4.3
• zlib-0.6.2.3

There's about 400 of build failures. Some are due to environment (missing native libs) but many of them are due to dependency on (some of) these 8 (about 350 on zlib, it seems). To investigate into these 400 I'd need quick patches for these 8 packages (I already had patches for 3 of them though, fgl, lzma, double-conversion). Not sure when I get around to do it, but probably no earlier than Sunday.

[andreasabel]

@ulysses4ever

Meanwhile, another breakage is in regex-tdfa (failable patterns).

How should we communicate the fixed package to you?
I can easily fix this error, but there may be more; GHC aborts at the first error.
In the meantime, the fix is here: haskell-hvr/regex-tdfa#29
Location: https://github.com/haskell-hvr/regex-tdfa/pull/29/files#diff-32adf9fa2b97b309ce49d4c8198f514329aaf2bfc737262f4d4e72dd8dfb14dcR243

Update: fix also a second occurrence of the same pattern:
https://github.com/haskell-hvr/regex-tdfa/pull/29/files#diff-6f1582818f0d271f987905c7d77395bf709a0853462d45d236a6b24e9442afa3R288