haskell · geekosaur · Mar 19, 2026
diff --git a/.github/workflows/bootstrap.yml b/.github/workflows/bootstrap.yml
@@ -19,7 +19,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        ghc: ["9.2.8", "9.4.8", "9.6.7", "9.8.4", "9.10.2", "9.12.2"]
+        ghc: ["9.2.8", "9.4.8", "9.6.7", "9.8.4", "9.10.3", "9.12.2"]
         include:
           - os: macos-latest
             ghc: "9.2.8"

diff --git a/Makefile b/Makefile
@@ -49,7 +49,7 @@ FORMAT_DIRS_TODO := \
 	solver-benchmarks
 
 .PHONY: style-todo
-style-todo: ## Configured for fourmolu, avoiding GHC parser failures
+style-todo: ## Configured for fourmolu, avoiding GHC parser failures.
 	@fourmolu -q $(FORMAT_DIRS_TODO) > /dev/null
 
 .PHONY: style
@@ -85,7 +85,7 @@ lint-json: ## Run HLint in JSON mode.
 # local checks
 
 .PHONY: checks
-checks: whitespace users-guide-typos markdown-typos style lint-json  ## Run all local checks; whitespace, typos, style, and lint.
+checks: whitespace users-guide-typos markdown-typos style lint-json  ## Run all local checks: whitespace, typos, style, and lint.
 
 # source generation: SPDX
 
@@ -265,17 +265,53 @@ tags: ## Generate editor tags, vim ctags and emacs etags.
 # bootstrapping
 ##############################################################################
 
+BOOT_GHCUP := $(shell ghcup --version 2>/dev/null)
+BOOT_NIX := $(shell nix-shell --version 2>/dev/null)
+CABALCONF := $(shell if test -f $$HOME/.config/cabal/config; then echo CABAL_CONFIG=$$HOME/.config/cabal/config; fi)
+
 bootstrap-json-%: phony
-	cabal build --project-file=cabal.bootstrap.project --with-compiler=ghc-$* --dry-run cabal-install:exe:cabal
-	cp dist-newstyle/cache/plan.json bootstrap/linux-$*.plan.json
+	ghcup install ghc "$*" --no-verbose --no-guess-version
+	$(MAKE) "bootstrap-subr-$*"
+
+# "subroutine", make style
+bootstrap-subr-%: phony
+	rm -rf dist-bootstrap
+	$(CABALBUILD) --distdir=dist-bootstrap --project-file=cabal.bootstrap.project --with-compiler=ghc-$* --dry-run \
+		cabal-install:exe:cabal
+	cp dist-bootstrap/cache/plan.json bootstrap/linux-$*.plan.json
 	@# -v0 to avoid build output on stdout
-	cd bootstrap && cabal run -v0 cabal-bootstrap-gen -- linux-$*.plan.json \
+	cd bootstrap && $(CABALCONF) $(CABALRUN) -v0 cabal-bootstrap-gen -- linux-$*.plan.json \
 		| python3 -m json.tool > linux-$*.json
 
-BOOTSTRAP_GHC_VERSIONS := 9.2.8 9.4.8 9.6.7 9.8.4 9.10.2 9.12.2
+BOOTSTRAP_GHC_VERSIONS := 9.2.8 9.4.8 9.6.7 9.8.4 9.10.3 9.12.2
 
 .PHONY: bootstrap-jsons
-bootstrap-jsons: $(BOOTSTRAP_GHC_VERSIONS:%=bootstrap-json-%)
+bootstrap-jsons: ## Generate bootstrap JSONs for Linux (autodetects method).
+ifeq ($(BOOT_GHCUP), )
+ifeq ($(BOOT_NIX), )
+	@echo If you do not have ghcs $(BOOTSTRAP_GHC_VERSIONS), you will need to install them manually.
+	$(MAKE) bootstrap-jsons-no-dl
+else
+	$(MAKE) bootstrap-jsons-nix
+endif
+else
+	$(MAKE) bootstrap-jsons-ghcup
+endif
+
+.PHONY: bootstrap-jsons-no-dl
+bootstrap-jsons-no-dl: $(BOOTSTRAP_GHC_VERSIONS:%=bootstrap-subr-%) ## Generate bootstrap JSONs for Linux using existing ghcs.
+
+.PHONY: bootstrap-jsons-nix
+bootstrap-jsons-nix: ## Generate bootstrap JSONs for Linux using Nix-provided ghcs.
+	cd ./bootstrap && $(CABALCONF) ./generate_bootstrap_plans
+
+.PHONY: bootstrap-jsons-ghcup
+bootstrap-jsons-ghcup: $(BOOTSTRAP_GHC_VERSIONS:%=bootstrap-json-%) ## Generate bootstrap JSONs for Linux using ghcup.
+
+# this lets the Nix bootstrap script use the Makefile's definitions instead of hardcoding them itself
+.PHONY: bootstrap-jsons-nix-helper
+bootstrap-jsons-nix-helper:
+	@echo "$(BOOTSTRAP_GHC_VERSIONS)"
 
 # documentation
 ##############################################################################
@@ -290,45 +326,45 @@ else
 PROCS := $(shell nproc)
 endif
 
-PHONY: help
+.PHONY: help
 help: ## Show the commented targets.
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | \
 	sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
 
-PHONY: help-banner
+.PHONY: help-banner
 help-banner: ## Show the help banner.
 	@echo "===================================================================="
 	@echo "§ all                  make with no arguments also shows this banner"
 	@echo "§ help                 make help will list targets with descriptions"
 	@echo "===================================================================="
 
 .PHONY: typos-install
-typos-install: ## Install typos-cli for typos target using cargo
+typos-install: ## Install typos-cli for typos target using cargo.
 	cargo install typos-cli
 
 GREP_EXCLUDE := grep -v -E 'dist-|cabal-testsuite|python-'
 FIND_NAMED := find . -type f -name
 
 .PHONY: hs-typos
-hs-typos: ## Find typos in Haskell source files; .hs, .cabal, etc.
+hs-typos: ## Find typos in Haskell source files: .hs, .cabal, etc.
 	typos --config .typos-srcs.toml --force-exclude
 
 .PHONY: hs-fix-typos
-hs-fix-typos: ## Fix typos in Haskell source files; .hs, .cabal, etc.
+hs-fix-typos: ## Fix typos in Haskell source files: .hs, .cabal, etc.
 	typos --config .typos-srcs.toml --write-changes --force-exclude
 
 .PHONY: users-guide-typos
-users-guide-typos: ## Find typos in users guide
+users-guide-typos: ## Find typos in users guide.
 	cd doc && $(FIND_NAMED) '*.rst' | xargs typos --config ../.typos-docs.toml --force-exclude
 
 .PHONY: users-guide-fix-typos
-users-guide-fix-typos: ## Fix typos in users guide
+users-guide-fix-typos: ## Fix typos in users guide.
 	cd doc && $(FIND_NAMED) '*.rst' | xargs typos --config ../.typos-docs.toml --write-changes --force-exclude 
 
 .PHONY: markdown-typos
-markdown-typos: ## Find typos in markdown files
+markdown-typos: ## Find typos in markdown files.
 	$(FIND_NAMED) '*.md' | $(GREP_EXCLUDE) | xargs typos --config .typos-docs.toml --force-exclude
 
 .PHONY: markdown-fix-typos
-markdown-fix-typos: ## Fix typos in markdown files
+markdown-fix-typos: ## Fix typos in markdown files.
 	$(FIND_NAMED) '*.md' | $(GREP_EXCLUDE) | xargs typos --config .typos-docs.toml --write-changes --force-exclude
diff --git a/bootstrap/README.md b/bootstrap/README.md
@@ -33,7 +33,7 @@ in the same way as it is shown for Linux above. On a system with functional `cab
 
 1. Install the same GHC version as you will use to bootstrap on the host system.
 
-2. Build a dependency description file (`$PLATFORM-$GHCVER.json`, e.g. `macosx-8.8.4.json`) by running:
+2. Build a dependency description file (`$PLATFORM-$GHCVER.json`, e.g. `macosx-8.8.4.json`).
 
    ```sh
    cabal build --with-compiler=/path/to/ghc --dry-run cabal-install:exe:cabal
@@ -45,15 +45,8 @@ in the same way as it is shown for Linux above. On a system with functional `cab
 3. You may need to tweak `bootstrap/$PLATFORM-$GHCVER.json` file manually,
      for example, to toggle flags.
 
-There are rules in the top-level `Makefile` for generation of these files.
-
-# Updating Bootstrap Plans
-
-In order to update the bootstrap plans on linux there is the convenient `./generate_bootstrap_plans`
-script. You can modify this script with the GHC versions you want to generate the plans for and
-then run it to generate the plans.
-
-```
-./generate_bootstrap_plans
-```
-
+The top level `Makefile` has a rule `bootstrap-jsons` to generate Linux bootstrap files for all
+supported ghc versions, or `bootstrap-json-$GHCVER` for a single ghc version. The rules know
+how to obtain the requisite ghc versions via `ghcup` or Nix; if you have neither, you will
+have to obtain versioned ghc binaries from `downloads.haskell.org` or other suitable
+repository.
diff --git a/bootstrap/cabal-bootstrap-gen.cabal b/bootstrap/cabal-bootstrap-gen.cabal
@@ -9,8 +9,8 @@ executable cabal-bootstrap-gen
   main-is:          Main.hs
   build-depends:
     , aeson                  ^>=1.5.2.0  || ^>=2.0.3.0 || ^>=2.1.0.0 || ^>=2.2.0.0
-    , base                   ^>=4.12.0.0 || ^>=4.13.0.0 || ^>=4.14.0.0 || ^>=4.15.0.0 || ^>=4.16.0.0 || ^>=4.17.0.0 || ^>=4.18.0.0 || ^>=4.19.0.0 || ^>=4.20.0.0
-    , bytestring             ^>=0.10.8.2 || ^>=0.11.0.0
+    , base                    >=4.12.0.0 && < 5
+    , bytestring              >=0.10.8.2 && <0.13
     , Cabal                  ^>=3.14.1.0 || ^>=3.16.0.0
     , Cabal-syntax           ^>=3.14.1.0 || ^>=3.16.0.0
         -- For the release process, we need the last *two* Cabal-syntax
@@ -20,7 +20,8 @@ executable cabal-bootstrap-gen
         -- rerun `make bootstrap-jsons`.
     , cabal-install-parsers  ^>=0.6
     , cabal-plan             ^>=0.7.0.0
-    , containers             ^>=0.6.0.1
-    , text                   ^>=1.2.3.0  || ^>=2.0.1
+    -- upper bound is conjectural
+    , containers              >=0.6.0.1  && <0.10
+    , text                    >=1.2.3.0  && <3
     , topograph              ^>=1.0.0.1
     , transformers           ^>=0.5.6.2  || ^>=0.6.0.4
diff --git a/bootstrap/generate_bootstrap_plans b/bootstrap/generate_bootstrap_plans
@@ -1,23 +1,27 @@
-nix build nixpkgs#jq.bin -o jq
-PATH+=:$PWD/jq-bin/bin
+#! /bin/sh
+nix build nixpkgs#jq.bin -o jq --extra-experimental-features nix-command --extra-experimental-features flakes
+PATH="$PATH:$PWD/jq-bin/bin"
 
 ghcs_nix="https://gitlab.haskell.org/bgamari/ghcs-nix/-/archive/master/ghcs-nix-master.tar.gz"
 
-nix build -f "$ghcs_nix" ghc-9_6_5 -o boot_ghc
+nix build -f "$ghcs_nix" ghc-9_6_5 -o boot_ghc --extra-experimental-features nix-command
 
 run() {
   local ver="$1"
   local drv="ghc-$ver"
   echo "$ver"
-  nix build -f "$ghcs_nix" $drv
-  (cd ../; rm -r dist-bootstrap; cabal --distdir=dist-bootstrap build --project-file=cabal.bootstrap.project --dry-run cabal-install:exe:cabal -w bootstrap/result/bin/ghc)
+  nix build -f "$ghcs_nix" $drv --extra-experimental-features nix-command
+  (cd .. && rm -rf dist-bootstrap && cabal --distdir=dist-bootstrap build --project-file=cabal.bootstrap.project --dry-run cabal-install:exe:cabal -w bootstrap/result/bin/ghc)
   jq --sort-keys < ../dist-bootstrap/cache/plan.json > "plan-$ver.json"
   cabal run --with-ghc-pkg $PWD/boot_ghc/bin/ghc-pkg -w $PWD/boot_ghc/bin/ghc -v0 cabal-bootstrap-gen -- "plan-$ver.json" | jq --sort-keys | tee "linux-$(echo $ver | tr "_" ".").json"
 }
 
-run "9_2_8"
-run "9_4_8"
-run "9_6_7"
-run "9_8_4"
-run "9_10_1"
-run "9_12_2"
+if [ $# -eq 0 ]; then
+  # get bootstrap ghc list from Makefile instead of hardcoded
+  # MAKELEVEL silences sub-make output if this is run from the top level Makefile
+  set -- $(cd ..; MAKELEVEL= make bootstrap-jsons-nix-helper)
+fi
+
+for ghc in "$@"; do
+  run $(echo "$ghc" | tr . _)
+done
diff --git a/bootstrap/linux-9.10.2.json → bootstrap/linux-9.10.3.json b/bootstrap/linux-9.10.2.json → bootstrap/linux-9.10.3.json
@@ -14,11 +14,11 @@
         },
         {
             "package": "ghc-internal",
-            "version": "9.1002.0"
+            "version": "9.1003.0"
         },
         {
             "package": "base",
-            "version": "4.20.1.0"
+            "version": "4.20.2.0"
         },
         {
             "package": "array",
@@ -30,7 +30,7 @@
         },
         {
             "package": "ghc-boot-th",
-            "version": "9.10.2"
+            "version": "9.10.3"
         },
         {
             "package": "pretty",
@@ -66,7 +66,7 @@
         },
         {
             "package": "os-string",
-            "version": "2.0.4"
+            "version": "2.0.7"
         },
         {
             "package": "filepath",
@@ -78,7 +78,7 @@
         },
         {
             "package": "unix",
-            "version": "2.8.6.0"
+            "version": "2.8.7.0"
         },
         {
             "package": "directory",
@@ -90,7 +90,7 @@
         },
         {
             "package": "text",
-            "version": "2.1.2"
+            "version": "2.1.3"
         },
         {
             "package": "parsec",