{"action":"created","issue":{"url":"https://api.github.com/repos/commercialhaskell/stack/issues/4406","repository_url":"https://api.github.com/repos/commercialhaskell/stack","labels_url":"https://api.github.com/repos/commercialhaskell/stack/issues/4406/labels{/name}","comments_url":"https://api.github.com/repos/commercialhaskell/stack/issues/4406/comments","events_url":"https://api.github.com/repos/commercialhaskell/stack/issues/4406/events","html_url":"https://github.com/commercialhaskell/stack/issues/4406","id":382001580,"node_id":"MDU6SXNzdWUzODIwMDE1ODA=","number":4406,"title":"Performance overheard with nix integration.","user":{"login":"chrissound","id":1499652,"node_id":"MDQ6VXNlcjE0OTk2NTI=","avatar_url":"https://avatars0.githubusercontent.com/u/1499652?v=4","gravatar_id":"","url":"https://api.github.com/users/chrissound","html_url":"https://github.com/chrissound","followers_url":"https://api.github.com/users/chrissound/followers","following_url":"https://api.github.com/users/chrissound/following{/other_user}","gists_url":"https://api.github.com/users/chrissound/gists{/gist_id}","starred_url":"https://api.github.com/users/chrissound/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/chrissound/subscriptions","organizations_url":"https://api.github.com/users/chrissound/orgs","repos_url":"https://api.github.com/users/chrissound/repos","events_url":"https://api.github.com/users/chrissound/events{/privacy}","received_events_url":"https://api.github.com/users/chrissound/received_events","type":"User","site_admin":false},"labels":[{"id":259640588,"node_id":"MDU6TGFiZWwyNTk2NDA1ODg=","url":"https://api.github.com/repos/commercialhaskell/stack/labels/component:%20ghci","name":"component: ghci","color":"bfdadc","default":false},{"id":309727666,"node_id":"MDU6TGFiZWwzMDk3Mjc2NjY=","url":"https://api.github.com/repos/commercialhaskell/stack/labels/component:%20nix","name":"component: nix","color":"bfdadc","default":false},{"id":218432969,"node_id":"MDU6TGFiZWwyMTg0MzI5Njk=","url":"https://api.github.com/repos/commercialhaskell/stack/labels/type:%20performance","name":"type: performance","color":"fad8c7","default":false}],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":1,"created_at":"2018-11-18T21:21:37Z","updated_at":"2018-11-20T15:53:27Z","closed_at":null,"author_association":"NONE","body":"I've recently migrated to Nixos, and have started using `nix` with stack. However this seems to add considerable delay to starting ghci for things like ghcid / intero - something I normally wouldn't notice is now taking 5s +\\-.\r\n\r\nI'm not too familiar with what Nix is doing, but possibly there is a way to cache something or mount something in a ramfile (tmpfs iirc)?\r\n\r\nOutput of stack -v ghci app:\r\n```\r\n1.9.1 x86_64 hpack-0.31.0\r\n2018-11-18 21:11:25.371137: [debug] Checking for project config at: /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/stack.yaml\r\n2018-11-18 21:11:25.371426: [debug] Loading project config file stack.yaml\r\n2018-11-18 21:11:25.374024: [debug] Decoding build plan from: /home/chris/.stack/build-plan/lts-12.12.yaml\r\n2018-11-18 21:11:25.374136: [debug] Trying to decode /home/chris/.stack/build-plan-cache/lts-12.12.cache\r\n2018-11-18 21:11:25.381773: [debug] Success decoding /home/chris/.stack/build-plan-cache/lts-12.12.cache\r\n2018-11-18 21:11:25.382056: [debug] PATH is: Just \"/home/chris/.local/bin/:/home/chris/bin:/run/wrappers/bin:/etc/profiles/per-user/chris/bin:/home/chris/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/run/current-system/sw/bin:/home/chris/.local/bin\"\r\n2018-11-18 21:11:25.382142: [debug] Using a nix-shell environment with nix packages: zlib.dev, zlib.out, haskell.compiler.ghc843, git, gcc, gmp\r\n2018-11-18 21:11:25.382479: [debug] Run process: /run/current-system/sw/bin/nix-shell --pure -E \"with (import <nixpkgs> {}); let inputs = [zlib.dev zlib.out haskell.compiler.ghc843 git gcc gmp]; libPath = lib.makeLibraryPath inputs; stackExtraArgs = lib.concatMap (pkg: [ ''--extra-lib-dirs=${lib.getLib pkg}/lib''   ''--extra-include-dirs=${lib.getDev pkg}/include'' ]) inputs; in runCommand ''myEnv'' { buildInputs = lib.optional stdenv.isLinux glibcLocales ++ inputs; STACK_PLATFORM_VARIANT=''nix''; STACK_IN_NIX_SHELL=1; LD_LIBRARY_PATH = libPath;STACK_IN_NIX_EXTRA_ARGS = stackExtraArgs; } \\\"\\\"\" --run \"'/nix/store/anrbbqw3v0zgb0gypv9vskf59yfs3pbm-stack-1.9.1/bin/stack' $STACK_IN_NIX_EXTRA_ARGS '--internal-re-exec-version=1.9.1' '-v' 'ghci' 'app'\"\r\n1.9.1 x86_64 hpack-0.31.0\r\n2018-11-18 21:11:27.616683: [debug] Checking for project config at: /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/stack.yaml\r\n2018-11-18 21:11:27.616988: [debug] Loading project config file stack.yaml\r\n2018-11-18 21:11:27.623744: [debug] Decoding build plan from: /home/chris/.stack/build-plan/lts-12.12.yaml\r\n2018-11-18 21:11:27.623886: [debug] Trying to decode /home/chris/.stack/build-plan-cache/lts-12.12.cache\r\n2018-11-18 21:11:27.632732: [debug] Success decoding /home/chris/.stack/build-plan-cache/lts-12.12.cache\r\n2018-11-18 21:11:27.632898: [debug] Getting system compiler version\r\n2018-11-18 21:11:27.633125: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc --info\r\n2018-11-18 21:11:27.751692: [debug] Process finished in 118ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc --info\r\n2018-11-18 21:11:27.754339: [debug] Asking GHC for its version\r\n2018-11-18 21:11:27.754587: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc --numeric-version\r\n2018-11-18 21:11:27.755750: [debug] Getting Cabal package version\r\n2018-11-18 21:11:27.756307: [debug] Getting global package database location\r\n2018-11-18 21:11:27.756410: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --no-user-package-db field --simple-output Cabal version\r\n2018-11-18 21:11:27.757184: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --no-user-package-db list --global\r\n2018-11-18 21:11:27.834491: [debug] Process finished in 77ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --no-user-package-db list --global\r\n2018-11-18 21:11:27.846129: [debug] Process finished in 90ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --no-user-package-db field --simple-output Cabal version\r\n2018-11-18 21:11:27.854536: [debug] Process finished in 100ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc --numeric-version\r\n2018-11-18 21:11:27.855253: [debug] GHC version is: ghc-8.4.3\r\n2018-11-18 21:11:27.855372: [debug] Resolving package entries\r\n2018-11-18 21:11:27.855535: [debug] Trying to decode /home/chris/.stack/loaded-snapshot-cache/x86_64-linux-nix/ghc-8.4.3/lts-12.12.cache\r\n2018-11-18 21:11:27.926332: [debug] Success decoding /home/chris/.stack/loaded-snapshot-cache/x86_64-linux-nix/ghc-8.4.3/lts-12.12.cache\r\n2018-11-18 21:11:27.928398: [debug] Starting to execute command inside EnvConfig\r\n2018-11-18 21:11:27.928525: [debug] Parsing the targets\r\n2018-11-18 21:11:27.928796: [debug] Running hpack on /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/package.yaml\r\n2018-11-18 21:11:27.932962: [debug] hpack output unchanged in /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/app.cabal\r\n2018-11-18 21:11:27.935342: [debug] Trying to decode /home/chris/.stack/indices/Hackage/01-index.cache\r\n2018-11-18 21:11:28.287698: [debug] Success decoding /home/chris/.stack/indices/Hackage/01-index.cache\r\n2018-11-18 21:11:28.330095: [debug] Start: getPackageFiles /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/app.cabal\r\n2018-11-18 21:11:28.333248: [debug] Finished in 3ms: getPackageFiles /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/app.cabal\r\n2018-11-18 21:11:28.333513: [debug] Exception ignored when attempting to load /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/stack-build-caches/exe-app: /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/stack-build-caches/exe-app: openBinaryFile: does not exist (No such file or directory)\r\n2018-11-18 21:11:28.335793: [debug] Parsing the targets\r\n2018-11-18 21:11:28.366899: [debug] Finding out which packages are already installed\r\n2018-11-18 21:11:28.367333: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --global --no-user-package-db dump --expand-pkgroot\r\n2018-11-18 21:11:28.460505: [debug] Process finished in 93ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --global --no-user-package-db dump --expand-pkgroot\r\n2018-11-18 21:11:28.460765: [debug] Ignoring package text due to wanting version 1.2.3.1 instead of 1.2.3.0\r\n2018-11-18 21:11:28.461256: [debug] Ignoring package haskeline due to wanting version 0.7.4.3 instead of 0.7.4.2\r\n2018-11-18 21:11:28.461547: [debug] Ignoring package stm due to wanting version 2.4.5.1 instead of 2.4.5.0\r\n2018-11-18 21:11:28.461850: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/.stack/snapshots/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:28.806107: [debug] Process finished in 344ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/.stack/snapshots/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:28.811633: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/install/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:28.885053: [debug] Process finished in 73ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/install/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:28.885905: [debug] Start: getPackageFiles /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/app.cabal\r\n2018-11-18 21:11:28.888947: [debug] Finished in 3ms: getPackageFiles /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/app.cabal\r\n2018-11-18 21:11:28.895785: [info] Using main module: 1. Package `app' component exe:app with main-is file: /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/src/Main.hs\r\n2018-11-18 21:11:28.895965: [debug] Parsing the targets\r\n2018-11-18 21:11:28.927028: [debug] Start: getPackageFiles /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/app.cabal\r\n2018-11-18 21:11:28.930181: [debug] Finished in 3ms: getPackageFiles /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/app.cabal\r\n2018-11-18 21:11:28.930447: [debug] Exception ignored when attempting to load /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/stack-build-caches/exe-app: /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/stack-build-caches/exe-app: openBinaryFile: does not exist (No such file or directory)\r\n2018-11-18 21:11:28.932038: [debug] Finding out which packages are already installed\r\n2018-11-18 21:11:28.932235: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --global --no-user-package-db dump --expand-pkgroot\r\n2018-11-18 21:11:29.029916: [debug] Process finished in 98ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --global --no-user-package-db dump --expand-pkgroot\r\n2018-11-18 21:11:29.030245: [debug] Ignoring package text due to wanting version 1.2.3.1 instead of 1.2.3.0\r\n2018-11-18 21:11:29.030702: [debug] Ignoring package haskeline due to wanting version 0.7.4.3 instead of 0.7.4.2\r\n2018-11-18 21:11:29.030961: [debug] Ignoring package stm due to wanting version 2.4.5.1 instead of 2.4.5.0\r\n2018-11-18 21:11:29.031837: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/.stack/snapshots/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:29.374383: [debug] Process finished in 342ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/.stack/snapshots/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:29.379732: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/install/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:29.453281: [debug] Process finished in 73ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/install/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:29.454027: [debug] Constructing the build plan\r\n2018-11-18 21:11:29.607116: [debug] Checking if we are going to build multiple executables with the same name\r\n2018-11-18 21:11:29.607319: [debug] Executing the build plan\r\n2018-11-18 21:11:29.608772: [debug] Getting global package database location\r\n2018-11-18 21:11:29.608882: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --no-user-package-db list --global\r\n2018-11-18 21:11:29.684047: [debug] Process finished in 75ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --no-user-package-db list --global\r\n2018-11-18 21:11:29.684703: [info] Building all executables for `app' once. After a successful build of all of them, only specified executables will be rebuilt.\r\n2018-11-18 21:11:29.685727: [info] app-0.1.0.0: initial-build-steps (exe)\r\n2018-11-18 21:11:29.686065: [debug] Run process within /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/: /home/chris/.stack/setup-exe-cache/x86_64-linux-nix/Cabal-simple_mPHDZzAJ_2.2.0.1_ghc-8.4.3 --builddir=.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1 repl stack-initial-build-steps\r\n2018-11-18 21:11:29.770487: [debug] Process finished in 84ms: /home/chris/.stack/setup-exe-cache/x86_64-linux-nix/Cabal-simple_mPHDZzAJ_2.2.0.1_ghc-8.4.3 --builddir=.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1 repl stack-initial-build-steps\r\n2018-11-18 21:11:29.770861: [debug] Finding out which packages are already installed\r\n2018-11-18 21:11:29.771109: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --global --no-user-package-db dump --expand-pkgroot\r\n2018-11-18 21:11:29.869445: [debug] Process finished in 98ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --global --no-user-package-db dump --expand-pkgroot\r\n2018-11-18 21:11:29.869680: [debug] Ignoring package text due to wanting version 1.2.3.1 instead of 1.2.3.0\r\n2018-11-18 21:11:29.870158: [debug] Ignoring package haskeline due to wanting version 0.7.4.3 instead of 0.7.4.2\r\n2018-11-18 21:11:29.870952: [debug] Ignoring package stm due to wanting version 2.4.5.1 instead of 2.4.5.0\r\n2018-11-18 21:11:29.871194: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/.stack/snapshots/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:30.214190: [debug] Process finished in 343ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/.stack/snapshots/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:30.219660: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/install/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:30.295848: [debug] Process finished in 76ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc-pkg --user --no-user-package-db --package-db /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/install/x86_64-linux-nix/lts-12.12/8.4.3/pkgdb dump --expand-pkgroot\r\n2018-11-18 21:11:30.296494: [debug] Start: getPackageFiles /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/app.cabal\r\n2018-11-18 21:11:30.299420: [debug] Finished in 3ms: getPackageFiles /home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/app.cabal\r\n2018-11-18 21:11:30.307238: [info] Configuring GHCi with the following packages: app\r\n2018-11-18 21:11:30.308359: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc --version\r\n2018-11-18 21:11:30.409289: [debug] Process finished in 101ms: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc --version\r\n2018-11-18 21:11:30.409599: [debug] Run process: /nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/bin/ghc --interactive -i -odir=/home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/odir -hidir=/home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/odir -hide-all-packages -i/home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/app -i/home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/src -i/home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/app/autogen -i/home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/global-autogen -i/home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build/app/app-tmp -stubdir=/home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/dist/x86_64-linux-nix/Cabal-2.2.0.1/build -I/nix/store/0cra95pqdhh33wi730bnc0mq2jwixlrr-gmp-6.1.2-dev/include -I/nix/store/0w330s2s7xiq31api8lfhydbc13896sb-zlib-1.2.11-dev/include -I/nix/store/3ni1gjg15klcc8x52x71ip5jx9blj5zx-git-2.16.5/include -I/nix/store/8c30dl4mmgm4rip1l08fvad9gca5sk2j-zlib-1.2.11/include -I/nix/store/9y2f87qb1djmpjs1gxl6smfkpl581waa-gcc-wrapper-7.3.0/include -I/nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/include -L/nix/store/0w330s2s7xiq31api8lfhydbc13896sb-zlib-1.2.11-dev/lib -L/nix/store/3ni1gjg15klcc8x52x71ip5jx9blj5zx-git-2.16.5/lib -L/nix/store/8c30dl4mmgm4rip1l08fvad9gca5sk2j-zlib-1.2.11/lib -L/nix/store/9y2f87qb1djmpjs1gxl6smfkpl581waa-gcc-wrapper-7.3.0/lib -L/nix/store/dpd9k7q08wvb6d1a67h66amcazv5sy39-ghc-8.4.3/lib -L/nix/store/wc2ll61lypsv9yig6mvy73c0lw1dp15a-gmp-6.1.2/lib -package-id=aeson-1.3.1.1-1OkqdtyvGki5l4J1NAv2t2 -package-id=base-4.11.1.0 -package-id=binary-0.8.5.1 -package-id=binary-orphans-0.1.8.0-39x4G6qSmgR8DCEznq5kuk -package-id=bytestring-0.10.8.2 -package-id=directory-1.3.1.5 -package-id=lens-4.16.1-GeAlAh4cVDbGTwh8cjNcYq -package-id=old-locale-1.0.0.7-26K7wLFR2jK44UeOklvTCh -package-id=pretty-simple-2.1.0.1-8ASs0wI9YI68ZBesbmgb1L -package-id=split-0.2.3.3-3fFb67BrTpqAjKImK4FBjR -package-id=stm-2.4.5.1-1n1oRyz2WxkGi5pMiXlR3y -package-id=string-conversions-0.4.0.1-EzMSOHvXmIDwYIHdiF4RR -package-id=text-1.2.3.1-8ApPkOe77J58YHRjtBm7I8 -package-id=time-1.8.0.2 -optP-include -optP/home/chris/chrishomeold/home/chris/Projects/Haskell/IoEitherApplic/.stack-work/ghci/88aa14ad/cabal_macros.h -ghci-script=/run/user/1000/haskell-stack-ghci/92d62735/ghci-script\r\nGHCi, version 8.4.3: http://www.haskell.org/ghc/  :? for help\r\n```\r\n\r\n\r\n\r\n```\r\n$ stack --version\r\nVersion 1.9.1, Git revision f9d0042c141660e1d38f797e1d426be4a99b2a3c (6168 commits) x86_64 hpack-0.31.0\r\n```\r\n\r\n### Method of installation\r\n\r\n* Nixos's `stack` package\r\n"},"comment":{"url":"https://api.github.com/repos/commercialhaskell/stack/issues/comments/440323152","html_url":"https://github.com/commercialhaskell/stack/issues/4406#issuecomment-440323152","issue_url":"https://api.github.com/repos/commercialhaskell/stack/issues/4406","id":440323152,"node_id":"MDEyOklzc3VlQ29tbWVudDQ0MDMyMzE1Mg==","user":{"login":"nh2","id":399535,"node_id":"MDQ6VXNlcjM5OTUzNQ==","avatar_url":"https://avatars1.githubusercontent.com/u/399535?v=4","gravatar_id":"","url":"https://api.github.com/users/nh2","html_url":"https://github.com/nh2","followers_url":"https://api.github.com/users/nh2/followers","following_url":"https://api.github.com/users/nh2/following{/other_user}","gists_url":"https://api.github.com/users/nh2/gists{/gist_id}","starred_url":"https://api.github.com/users/nh2/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nh2/subscriptions","organizations_url":"https://api.github.com/users/nh2/orgs","repos_url":"https://api.github.com/users/nh2/repos","events_url":"https://api.github.com/users/nh2/events{/privacy}","received_events_url":"https://api.github.com/users/nh2/received_events","type":"User","site_admin":false},"created_at":"2018-11-20T15:53:27Z","updated_at":"2018-11-20T15:53:27Z","author_association":"COLLABORATOR","body":"Right, as @dbaynard said, that's ~2.3 seconds for the `nix-shell` invocation.\r\n\r\nThere are only two things I can think of to improve the situation:\r\n\r\n* Make `nix`'s evaluation faster (not a Stack problem)\r\n* Write the above `nix-shell -E` expression that's generated by the `stack --nix` integration in a better way that makes the current `nix`'s evaluation faster somehow. I don't know if it is possible.\r\n\r\nThere may also be some nix related things that make other steps done by stack slower with the nix integration. For example, at least until recently, nix generated hug environment variables and amounts of linker flags, which made all programs called by stack (e.g. the eventual `ghc --make` invocation, or `ghc-pkg`) slower. Many of them were fixed, but it is possible that others remain.\r\n\r\n@chrissound For this latter point, if you have time for it, it would be interesting to see the same project built with `-v` on the same computer on non-NixOS, to see if it's _only_ `nix-shell` that slows it down, or if the other `[debug]` steps have shorter time differences in between as well.\r\n\r\nStack being uncomfortably slow with nix integration is certainly an issue UX-wise, which is good to track how it improves over time, but I don't have any immediate ideas on what can be done for it."}}
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