maintainers/scripts/haskell/regenerate-hackage-packages.sh: init

Introduces a script that can be used to update the Nix expressions for

the Haskell package set. In service of that, also

- introduces cabal2nix-latest, which pins the hackage2nix version used

- changes all-cabal-hashes to use fetchFromGitHub

- adds update-hackage.sh & update-cabal2nix-latest.sh & update-stackage.sh maintainer scripts

maintainers/scripts/haskell/regenerate-hackage-packages.sh

@@ -0,0 +1,20 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i bash -p coreutils haskellPackages.cabal2nix-latest -I nixpkgs=.
+
+# This script is used to regenerate nixpkgs' Haskell package set, using a tool
+# called hackage2nix. hackage2nix looks at
+# pkgs/development/haskell-modules/configuration-hackage2nix.yaml and generates
+# a Nix expression for package version specified there, using the Cabal files
+# from the Hackage database (available under all-cabal-hashes) and its
+# companion tool cabal2nix.
+#
+# Related scripts are update-hackage.sh, for updating the snapshot of the
+# Hackage database used by hackage2nix, and update-cabal2nix-latest.sh,
+# for updating the version of hackage2nix used to perform this task.
+
+set -euo pipefail
+
+extractionDerivation='with import ./. {}; runCommand "unpacked-cabal-hashes" { } "tar xf ${all-cabal-hashes} --strip-components=1 --one-top-level=$out"'
+unpacked_hackage="$(nix-build -E "$extractionDerivation" --no-out-link)"
+
+hackage2nix --hackage "$unpacked_hackage" --preferred-versions <(for n in "$unpacked_hackage"/*/preferred-versions; do cat "$n"; echo; done) --nixpkgs "$PWD" --config pkgs/development/haskell-modules/configuration-hackage2nix.yaml

maintainers/scripts/haskell/update-cabal2nix-latest.sh

@@ -0,0 +1,17 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i bash -p coreutils curl jq gnused haskellPackages.cabal2nix-latest -I nixpkgs=.
+
+# Updates cabal2nix-latest to the latest master of the nixos/cabal2nix repository.
+# See regenerate-hackage-packages.sh for details on the purpose of this script.
+
+set -euo pipefail
+
+# fetch current master HEAD from Github
+head_info="$(curl -H "Accept: application/vnd.github.v3+json" https://api.github.com/repos/NixOS/cabal2nix/branches/master)"
+# extract commit hash
+commit="$(jq -r .commit.sha <<< "$head_info")"
+# extract commit timestamp and convert to date
+date="$(date "--date=$(jq -r .commit.commit.committer.date <<< "$head_info")" +%F)"
+# generate nix expression from cabal file, replacing the version with the commit date
+echo '# This file defines cabal2nix-latest, used by maintainers/scripts/haskell/regenerate-hackage-packages.sh.' > pkgs/development/haskell-modules/cabal2nix-latest.nix
+cabal2nix "https://github.com/NixOS/cabal2nix/archive/$commit.tar.gz" | sed -e 's/version = ".*"/version = "'"$date"'"/' >> pkgs/development/haskell-modules/cabal2nix-latest.nix

maintainers/scripts/haskell/update-hackage.sh

@@ -0,0 +1,21 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i bash -p nix curl jq nix-prefetch-github -I nixpkgs=.
+
+# See regenerate-hackage-packages.sh for details on the purpose of this script.
+
+set -euo pipefail
+
+pin_file=pkgs/data/misc/hackage/pin.json
+current_commit="$(jq -r .commit $pin_file)"
+head_commit="$(curl -H "Accept: application/vnd.github.v3+json" https://api.github.com/repos/commercialhaskell/all-cabal-hashes/branches/hackage | jq -r .commit.sha)"
+
+if [ "$current_commit" != "$head_commit" ]; then
+   url="https://github.com/commercialhaskell/all-cabal-hashes/archive/$head_commit.tar.gz"
+   hash="$(nix-prefetch-url "$url")"
+   jq -n \
+     --arg commit "$head_commit" \
+     --arg hash "$hash" \
+     --arg url "$url" \
+     '{commit: $commit, url: $url, sha256: $hash}' \
+     > $pin_file
+fi

maintainers/scripts/haskell/update-stackage.sh

@@ -0,0 +1,51 @@
+#! /usr/bin/env bash
+
+set -eu -o pipefail
+
+tmpfile=$(mktemp "update-stackage.XXXXXXX")
+# shellcheck disable=SC2064
+trap "rm ${tmpfile} ${tmpfile}.new" 0
+
+curl -L -s "https://stackage.org/nightly/cabal.config" >"$tmpfile"
+version=$(sed -rn "s/^--.*http:..(www.)?stackage.org.snapshot.nightly-//p" "$tmpfile")
+
+# Create a simple yaml version of the file.
+sed -r \
+    -e '/^--/d' \
+    -e 's|^constraints:||' \
+    -e 's|^ +|  - |' \
+    -e 's|,$||' \
+    -e '/installed$/d' \
+    -e '/^$/d' \
+    < "${tmpfile}" | sort --ignore-case >"${tmpfile}.new"
+
+# Drop restrictions on some tools where we always want the latest version.
+sed -r \
+    -e '/ cabal-install /d' \
+    -e '/ cabal2nix /d' \
+    -e '/ cabal2spec /d' \
+    -e '/ distribution-nixpkgs /d' \
+    -e '/ git-annex /d' \
+    -e '/ hindent /d' \
+    -e '/ hledger/d' \
+    -e '/ hlint /d' \
+    -e '/ hoogle /d' \
+    -e '/ hopenssl /d' \
+    -e '/ jailbreak-cabal /d' \
+    -e '/ json-autotype/d' \
+    -e '/ language-nix /d' \
+    -e '/ shake /d' \
+    -e '/ ShellCheck /d' \
+    -e '/ stack /d' \
+    -e '/ weeder /d' \
+    < "${tmpfile}.new" > "${tmpfile}"
+
+# Drop the previous configuration ...
+# shellcheck disable=SC1004
+sed -e '/  # Stackage Nightly/,/^$/c \TODO\
+'   -i pkgs/development/haskell-modules/configuration-hackage2nix.yaml
+
+# ... and replace it with the new one.
+sed -e "/TODO/r $tmpfile" \
+    -e "s/TODO/  # Stackage Nightly $version/" \
+    -i pkgs/development/haskell-modules/configuration-hackage2nix.yaml