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https://github.com/peterbecich/cabal-resolver-issue
https://github.com/peterbecich/cabal-resolver-issue
Last synced: about 2 months ago
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- Host: GitHub
- URL: https://github.com/peterbecich/cabal-resolver-issue
- Owner: peterbecich
- License: bsd-3-clause
- Created: 2021-07-04T03:05:50.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2022-09-17T21:43:08.000Z (over 2 years ago)
- Last Synced: 2024-10-22T06:59:22.187Z (3 months ago)
- Language: Haskell
- Size: 670 KB
- Stars: 3
- Watchers: 4
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://github.com/peterbecich/cabal-resolver-issue/actions/workflows/ci.yml)
[](https://github.com/peterbecich/cabal-resolver-issue/actions/workflows/nix-cabal.yml)
[](https://github.com/peterbecich/cabal-resolver-issue/actions/workflows/nix-stack.yml)
Attempt to replicate issue https://github.com/haskell/cabal/issues/7466.
This is a Cabal project with an intricate dependency tree, but no source code. It was obfuscated using `obfuscate.hs`.
Run `cabal clean` followed by `cabal build all --dry-run`. The latter takes about 40 seconds locally to run, but is
faster on subsequent runs. Switching between `--enable-tests` and `--disable-test` incurs this 40-second cost again.
## `cabal configure`
```
% cabal clean
% cabal update
% time cabal configure
Resolving dependencies...
Build profile: -w ghc-8.10.4 -O1
...
cabal configure 43.40s user 9.81s system 52% cpu 1:42.08 total
% time cabal configure
'cabal.project.local' already exists, backing it up to 'cabal.project.local~'.
Build profile: -w ghc-8.10.4 -O1
...
cabal configure 7.67s user 2.02s system 54% cpu 17.941 total
```
## `cabal build all --dry-run`
```
% cabal clean
% cabal update
% time cabal build all --dry-run
Resolving dependencies...
Build profile: -w ghc-8.10.4 -O1
...
cabal build all --dry-run 44.71s user 9.52s system 45% cpu 1:59.77 total
% time cabal build all --dry-run
Build profile: -w ghc-8.10.4 -O1
...
cabal build all --dry-run 8.51s user 2.14s system 56% cpu 18.757 total
```
## Other considerations
- Deleting `cabal.project.freeze` and compare with that
- Use the `master` branch of the Cabal project
## Package versions
- Cabal 3.4.0.0 (via ghcup)
- GHC 8.10.4 (via ghcup)
## Workflow
In https://github.com/haskell/cabal,
```
cabal install cabal-install --overwrite-policy=always
```
The bug is reproduced by switching between `enable-tests` and `disable-tests`.
In this repo, try
```
time ~/.cabal/bin/cabal build all --disable-tests --dry-run > disabled.log
```
and
```
time ~/.cabal/bin/cabal build all --enable-tests --dry-run > enabled.log
```
, then `diff disabled.log enabled.log`.
Also, try `--verbose:`
```
time ~/.cabal/bin/cabal build all --disable-tests --dry-run --verbose > disabled.log
time ~/.cabal/bin/cabal build all --enable-tests --dry-run --verbose > enabled.log
```
Print statements placed here
https://github.com/haskell/cabal/blob/ec3cf26ae6021b7ca9f496a39efbcba50e459015/cabal-install/src/Distribution/Client/ProjectPlanning.hs#L413-L416
indicate that the `improved-plan`
https://github.com/haskell/cabal/blob/ec3cf26ae6021b7ca9f496a39efbcba50e459015/doc/nix-local-build.rst#caching
changes, triggering the 30~40 second resolver.
### My results using Cabal 3.4
From disabled tests to enabled tests
```
cabal build all --disable-tests --dry-run > disabled.log
1.50s user 0.15s system 99% cpu 1.655 total
cabal build all --enable-tests --dry-run > enabled.log
30.89s user 0.79s system 99% cpu 31.790 total
```
See `disabled_to_enabled.diff`.
From enabled tests to disabled tests
```
cabal build all --enable-tests --dry-run > enabled.log
1.90s user 0.20s system 100% cpu 2.108 total
cabal build all --disable-tests --dry-run > disabled.log
29.72s user 0.85s system 99% cpu 30.668 total
```
See `enabled_to_disabled.diff`.
The message "cannot read state cache" is of interest. The message is defined here:
https://github.com/haskell/cabal/blob/ec3cf26ae6021b7ca9f496a39efbcba50e459015/cabal-install/src/Distribution/Client/ProjectOrchestration.hs#L954-L955